All posts tagged melt

Large Sections of Greenland Covered in Melt Ponds, Dark Snow

Over the past couple of days, temperatures across the Greenland Ice Sheet have really ramped up. The result has been a pretty significant mid-to-late season melt pulse. According to NSIDC, nearly 40 percent of the ice sheet surface has been affected by surface melt during recent days. And Greenland ice mass balance appears to have also taken a hit.

This surface melt pulse is, arguably, best portrayed in the satellite imagery:

(Large section of Western Greenland near the Jackobshavn Glacier experiencing significant surface melt on July 20, 2016. Image source: LANCE MODIS.)

On July 20th, this approximate 300 x 70 mile swath of Western Greenland shows a number of distinct strong melt features. Near the interior edge of the melt zone we notice the light blue coloration indicative of widespread and general surface melt. From the satellite, this bluing gives the impression of a thin layer of surface water covering a widespread area of the ice sheet. But it is more likely that the blue tint comes from a plethora of small melt ponds and rivers that blend together in the lower resolution satellite shot to lend the impression of ubiquitous water coverage.

Large Melt Ponds, Dark Snow Over Western Greenland

Further in, we notice the darker blue swatches that indicate large melt ponds. Some of these ponds are quite extensive — measuring 1/4 to up to 1 mile in length. Ponds of this size tend to put a lot of pressure on the Greenland surface and can pretty quickly bore down into the ice sheet’s depths and interior. The water then either becomes locked in the ice — forming a kind of subglacial lake — or flows to base regions of the glacier where it can lubricate the ice — causing it to speed up.

(Close up satellite shot shows 1/4 to 1 mile long melt ponds, general melt ponding and a darkened Greenland Ice Sheet. Image source: LANCE MODIS.)

Still closer to the ice edge we find greatly darkened patches of ice. Darkening occurs when ice melt reveals and thickens past layers of ice sheet dust and soot accumulation. Each year, winds carry dust from land masses and soot from fires — which now, due to rapid Earth warming, burn more frequently over the Arctic and near-Arctic — to the ice sheet where it accumulates. This darker material is then covered by the annual layers of snowfall. If enough snow and ice melts, the yearly layers of dust and soot accumulation can concentrate into a gray-black covering. Such a covering is clearly visible in the July 20 satellite imagery above.

According to Dr. Jason Box, as much as 5.6 percent of the Greenland Ice Sheet was covered by this darkening, which he calls Dark Snow, as recently as 2014. Darkening of the Greenland ice sheet can accelerate melt as it reduces the ice sheet’s ability to reflect the sun’s rays — resulting in more overall heat absorption.

Substantial Northeastern Greenland Melt Also Visible

(Zacharie Isstrom Glacier in Northeastern Greenland shows significant melt in July 20 satellite shot. Image source: LANCE MODIS.)

Though surface melt and darkening is quite extensive along the southwestern flank of Greenland, toward the north and east, widespread surface melt, ponding and ice darkening is also visible over sections of the Zachariae Glacier. Here, in a far northern section of Greenland that borders the Arctic Ocean, we find an approximate 100 x 20 mile region of melting and darkening ice. Note the tell-tale bluing and dark gray patches visible in the above image.

For this region, ice has tended to experience more melt during recent years as sea ice within the Fram Strait and Greenland Sea has receded. This has revealed more darker ocean surfaces which, in turn, has absorbed more incoming solar radiation resulting in increased warming for this section of Greenland.

Conditions in Context — Human-Forced Warming Pushing Greenland to Melt Faster

Overall, Greenland melt is this year less extensive than the record 2012 melt season. However, the current mid-to-late season pulse has forced a big melt acceleration that may result in melt that exceeds 250 billion tons of ice loss for 2016 (or the average over recent years). In the pretty near future, continued high global temperatures and additional warming due to human fossil fuel emissions will almost certainly push Greenland to melt at a faster pace.

To this point, the Earth has now warmed by more than 1 C above Preindustrial temperatures. And a range of 1-2 C warming from this baseline in past climate eras such as the Eemian resulted in a 10-20 foot rise in world ocean levels. We’re in this temperature range now. So that’s pretty bad news for sea level rise — to which Greenland now contributes enough melt to lift seas by about 0.75 mm every year. The only real questions at this point are how fast will that already substantial melt accelerate, and will we halt fossil fuel burning swiftly enough to slow it down.

Links/Attribution/Statements

LANCE MODIS

The National Snow and Ice Data Center

Greenland Surface Mass Budget

These Stunning Photos of Greenland’s Dark Snow Should Worry You

The Dark Snow Project (please support)

Hat tip to Andy in San Diego

Hat tip to DT Lange

Scribbler-sponsored note on Trump:

Trump Chooses Climate Change Denier as Energy Advisor

27 Comments

by robertscribbler on July 21, 2016 • Permalink

Posted in Climate Change

Tagged 2016 Melt Season, climate change, environment, extreme weather, global warming, greenland, greenland melt, Human Hothouse, human warming, melt, science, sea level rise, weather

Posted by robertscribbler on July 21, 2016

https://robertscribbler.wordpress.com/2016/07/21/large-sections-of-greenland-covered-in-melt-ponds-dark-snow/

Tottering Totten and the Coming Multi-Meter Sea Level Rise

A new scientific study has found that the Totten Glacier is fundamentally unstable and could significantly contribute to a possible multi-meter sea level rise this Century under mid-range and worst case warming scenarios.

*****

408 Parts per million CO2. 490 parts per million CO2e. This is the amount of heat-trapping CO2 and total CO2 equivalent for all heat-trapping gasses now in the Earth’s atmosphere. Two measures representing numerous grave potential consequences.

We’re Locking in 120-190 Feet of Sea Level Rise Long Term

Looking at the first number — 408 parts per million CO2 — we find that the last time global levels of this potent heat-trapping gas were so high was during the Middle Miocene Climate Optimum of 15-17 million years ago. During this time, the Greenland Ice Sheet did not exist. East Antarctic glacial ice was similarly scarce. And the towering glaciers of West Antarctica were greatly reduced. Overall, global sea levels were 120 to 190 feet higher than they are today. Meanwhile, atmospheric temperatures were between 3 and 5 degrees Celsius hotter than those experienced during the late 19th Century.

(Large sections of Antarctica rest below sea level. A physical feature that renders substantial portions of Antarctica’s glaciers very vulnerable to rising ocean temperatures. Since the latent heat content of water is substantially higher than that of air, even comparatively small ocean temperature increases can cause significant melt in sea-facing glaciers and in below sea level glacial basins. Image source: Potential Antarctic Ice Sheet Retreat Driven by Hydrofracturing and Ice Cliff Failure.)

Hitting the 408 ppm CO2 threshold this year catapults the current push for global climate transitions outside of the Pliocene context of 3 to 5 million years ago (topping out at 405 parts per million CO2) and places it in the bottom to mid-range of the Middle Miocene context (300 to 500 parts per million CO2). The 490 ppm CO2e number — due to added atmospheric heating contributions from human-emitted gasses like methane, chlorofluorocarbons, NOx compounds, and others — is enough to catapult our current climate context into the upper Middle Miocene range.

If global greenhouse gasses were to stabilize in this range long-term (for a period of hundreds of years), we would expect the Earth’s climate and ocean states to become more and more like those experienced 15-17 million years ago. Unfortunately, atmospheric concentrations of heat trapping gasses are still rapidly rising due to an increasingly dangerous emission coming from global fossil fuel burning. In addition, risks are rising that the Earth System will begin to contribute its own substantial amounts of carbon — possibly enough to raise the CO2e number by around 50 to 150 ppm over the next few centuries. Two contributions — one we control and another we do not — that risk swiftly pushing the global climate context into a 550 to 650 ppm CO2e range that is enough to eventually melt all the glacial ice on the planet.

Glacial Inertia vs Lightning Rates of Warming

It’s a tough climate state. A context that many scientists are still having difficulty coming to grips with. First, the global glacier research community is still looking at the world’s potential future ice melt in Pliocene and Eemian contexts. This makes some sense given the fact that current atmospheric warming in the range of 0.9 to 1.3 C above 1880s values is more in line with those two climate epochs (the Eemian saw seas 10-20 feet higher than today and the Pliocene saw seas at 25-75 feet higher). But it doesn’t take into account the underlying heat forcing and the likely climate end-state.

Second, we don’t really have a good grasp on how fast or slow glaciers will respond to the added heat we’re putting into the Earth System. We do know that at the end of the last ice age, melting glaciers contributed as much as 10 feet of sea level rise per Century. But this was during a time of comparatively slow global temperature increase at the rate of about 0.05 C per Century — not the current rate in the range of 1.5 to 2 C per Century, which is 30 to 40 times faster.

(What 10 feet of sea level rise would do to South Florida. Given the increasing vulnerability of glaciers around the world to human-forced warming, there’s a rising risk that seas could rise by 10 feet before the end of this Century. Image source: Climate Central.)

In early studies, much weight has been given to glacial inertia. And older climate models did not include dynamic ice sheet vulnerabilities — like high latent-heat ocean water coming into contact with the submerged faces of sea-fronting glaciers, the ability of surface melt water to break up glaciers by pooling into cracks and forcing them apart (hydrofracturing), or the innate rigidity and frailty of steep ice cliffs which render them susceptible to rapid toppling. But now, new studies are starting to take these physical melt-amplifying processes into account and the emerging picture is one in which glacial melt and sea level rise may end up coming on at rates far more rapid than previously feared.

Overall, when taking a look at these newly realized ice-sheet weaknesses, it’s worth noting that the total heat forcing impacting the world’s ocean, air, and glacial systems is now rising into a range that is much more in line with Middle Miocene values. And that global temperatures are now increasing at a lightning rate that appears to be unprecedented in at least the past 60 million years.

Tottering Totten

It’s in this dynamic, rapidly changing, and arguably quite dangerous climate context that new revelations about the stability of one of East Antarctica’s largest glaciers have begun to emerge. In size, the Totten Glacier is immense — covering an area the size of California in mountains of ice stretching as high as two and a half miles. If all of Totten were to melt, it would be enough to raise seas by around 11 to 13 feet — or about as much as if half of the entire Greenland Ice Sheet went down.

(The Totten Glacier, at lower edge of frame, faces a warming Southern Ocean. How rapidly this great mass of ice melts will, along with the destabilization of numerous other glaciers around the world due to a human-forced warming, determine the fates of numerous coastal cities and island nations during this Century and on into the future. Image source: LANCE-MODIS.)

Last year, a study found that warm, deep circumpolar water was beginning to approach ice faces of the Totten Glacier plunging 1 mile below the surface of the Southern Ocean. The study observed a rapid thinning that appeared to have been driven by this new influx of warmer ocean water near the glacier base:

Totten Glacier… has the largest thinning rate in East Antarctica. Thinning may be driven by enhanced basal melting… Warm modified Circumpolar Deep Water, which has been linked to glacier retreat in West Antarctica, has been observed in summer and winter on the nearby continental shelf beneath 400 to 500 m of cool Antarctic Surface Water…We identify entrances to the ice-shelf cavity below depths of 400 to 500 m that could allow intrusions of warm water if the vertical structure of inflow is similar to nearby observations. Radar sounding reveals a previously unknown inland trough that connects the main ice-shelf cavity to the ocean. If thinning trends continue, a larger water body over the trough could potentially allow more warm water into the cavity, which may, eventually, lead to destabilization of the low-lying region between Totten Glacier and the similarly deep glacier flowing into the Reynolds Trough (emphasis added).

Observed increasing melt rates for such a huge slab of ice in Eastern Antarctica was generally seen as a pretty big deal among glacial scientists and a flurry of additional research soon followed. By last week, a model study had found that Totten alone could produce nearly a meter of sea level rise before the end of this Century if global warming forces ocean waters to heat up by 2 C or more near the Totten Glacier. The study also found that 5 C worth of local ocean warming would be enough to force nearly 3 meters worth of sea level rise from this single large glacier over a relatively short time-frame.

Donald D. Blankenship, lead principal investigator for the new ICECAP study noted:

“Totten Glacier’s catchment is covered by nearly 2½ miles of ice, filling a California-sized sub-ice basin that reaches depths of over one mile below sea level. This study shows that this system could have a large impact on sea level in a short period of time.”

Like many large glaciers around the world, a huge portion of Totten’s ice sits below sea level. This feature makes the glacier very vulnerable to ocean warming. Water carries far more latent heat than air and just a slight rise in local ocean water temperature can contribute to rapid ice loss. Totten itself rests in three large below sea level basins. And study authors found that 2 C to 5 C warming of local ocean waters with somewhat greater local air temperature increases was capable of flooding these basins in stages — forcing Totten’s glacial ice to flow out into the Southern Ocean and provide significant contributions to sea level rise.

Unfortunately, Totten is just one of many large glacial systems that are now destabilizing across Antarctica. And researchers are now beginning to identify significant potential sea level rise contributions from Antarctica alone (ranging from two feet to nearly two meters) before the end of this Century. In New Scientist, during March, Antarctic researcher Rob Deconto notes:

“Today we’re measuring global sea level rise in millimetres per year. We’re talking about the potential for centimetres per year just from [ice loss in] Antarctica.”

Centimeters per year sea level rise is about ten times faster than current rates and implies 100 year increases — once it gets going — in the range of 2 to 3 meters. Such increased melt does not include Greenland’s own potential sea level rise contribution. Nor does it include sea level rise from other glacial melt and ocean thermal expansion. As such, it appears that multi-meter sea level rise is becoming a more and more distinct possibility this Century. Furthermore, the paleoclimate context is now pointing toward catastrophic levels of overall melt and sea level rise if global greenhouse gasses aren’t somehow stabilized and then swiftly reduced.

Links:

Repeated Large-Scale Retreat and Advance of Totten Glacier Indicated by Inland Bed Erosion

The Totten Glacier

The Human-Warmed Southern Ocean Threatens Major Melt for East Antarctica

Fundamentally Unstable — Scientists Confirm Their Fears About East Antarctica’s Biggest Glacier

Potential Antarctic Ice Sheet Retreat Driven by Hydrofracturing and Ice Cliff Failure

Unstable East Antarctic Glacier Has Contributed to Sea Level Rise in the Past

Sea Levels Set to Rise Far More Rapidly Than Expected

Unexpected Antarctic Melt Could Trigger 2 Meter Sea Level Rise

Entering the Middle Miocene

The Middle Miocene

LANCE MODIS

134 Comments

by robertscribbler on May 25, 2016 • Permalink

Posted in Climate Change

Tagged climate change, glacial melt, global warming, Human Hothouse, human warming, ICECAP, melt, Middle Miocene, Multi Meter Sea Level Rise, Pliocene, sea level rise, Totten Glacier, Totten Glacier Unstable

Posted by robertscribbler on May 25, 2016

https://robertscribbler.wordpress.com/2016/05/25/tottering-totten-and-the-coming-multi-meter-sea-level-rise/

Northeast Greenland Begins Ominous Collapse — Giant Zachariae Isstrom Most Recent to Destabilize

November 12, 2015:

North, south, east, and west. At all points of the compass, the entire outer edge of the Greenland Ice Sheet is flooding into the oceans with increasing velocity. For NASA it’s the absolute worst kind of OMG realization. For the world’s warming oceans and airs are clearly worsening an already visible Greenland melt. And a new report just out of the University of California (Irvine) today shows that a massive glacier containing enough water to raise seas by more than 1.6 feet (0.5 meters) is the most recent of a growing number of these ice giants to initiate a swift rush into the ocean.

Called Zachariæ Isstrøm, this enormous glacier dominates a large section of the northeast-facing shores of Greenland. The glacier, hundreds of feet tall and plunging hundreds more feet below the ocean surface, like many in our world, now faces the combined threat of warming airs and waters. A double insult that, according to researchers, over the past 15 years has led to first destabilization and then a rapid seaward acceleration.

(1975 to 2015 time lapse shows recent rapid retreat of the Zachariæ Isstrøm glacier’s front. The dark green line marks the 2003 extent of the glacial front. Note the rapid retreat through 2015 in lighter shades blending toward white. Image source: Jeremie Mouginot/UCI via Climate Central.)

According to the new study — Fast retreat of Zachariæ Isstrøm, northeast Greenland — published today in Science, the glacier’s rate of seaward movement has tripled in velocity even as the pace of ice thinning along its grounding line doubled:

Warmer air and ocean temperatures have caused the glacier to detach from a stabilizing sill and retreat rapidly along a downward-sloping, marine-based bed… After 8 years of decay of its ice shelf, Zachariæ Isstrøm, a major glacier of northeast Greenland that holds a 0.5-meter sea-level rise equivalent, entered a phase of accelerated retreat in fall 2012. The acceleration rate of its ice velocity tripled, melting of its residual ice shelf and thinning of its grounded portion doubled, and calving is now occurring at its grounding line.

In total, more than 4.5 billion tons of ice is now estimated to be flooding out from this glacier and into the ocean each year. That’s a mountain of ice about 4.5 cubic kilometers in size hitting the world’s waters from just this single glacier every time the Earth completes one circuit around the sun. In other words, Greenland just opened a new floodgate to the North Atlantic. Researchers publishing the study estimate that it will take between 20 and 30 years for the glacier to melt back to an underwater ridge line that should somewhat slow its melt. But the real news here is that a human-forced warming of the globe has set a monstrous pile of ice, once thought stable, into a motion that will result in yet more global sea level rise.

To the north of Zachariæ Isstrøm sits the also melting Nioghalvfjerdsfjorden. A giant of ice in equal volume to that of Zachariæ. Nioghalvfjerdsfjorden sits on an upward sloping bed and so is not as subject to rapid destabilization as Zachariæ. However, the study found that the combined total ice mass of both glaciers in the range of 1 meter worth of sea level rise was now involved in a significant melt that would “increase sea-level rise from the Greenland Ice Sheet for decades to come.”

(Map of Greenland topography showing large sections of the interior resting near or below sea level. As a result, warming waters have numerous avenues for invasion into the Greenland Ice Sheet. Numerous ways to melt Greenland ice from below. Zachariæ Isstrøm covers the upper right hand section of this image — sitting astride a low elevation channel the plunges deep into the heart of the current ice mass. Image source: Livescience.)

Greenland is the last major remaining bastion of glacial ice in the Northern Hemisphere. Surrounded on all sides by warming airs and waters, it is the most vulnerable large ice mass to the forces set in play by a human warming of the global environment. In total, Greenland holds enough ice to raise seas by 23 feet. And, in the geological past, just 1.5 to 2.5 degrees Celsius worth of temperature increase above Holocene averages was enough to melt much or all of it.

Currently, human warming by Greenhouse gasses has pushed global average surface temperatures into a range about 1 degree Celsius hotter than the 1880s. It’s a temperature running into ranges that are now comparable with the Eemian — the interglacial period that occurred between 115,000 to 130,000 years ago. A period when oceans were about 13 to 20 feet higher than they are today.

But perhaps even more concerning is the fact that global greenhouse gas concentrations in the range of 400 ppm CO2 and 485 ppm CO2e are enough now to warm the Earth by 2 to 4 degrees Celsius long-term. It’s a heat forcing that would likely spell the end for Greenland’s ice if it remained in place for any significant period. A heat forcing more comparable with Pliocene and Miocene ranges when the world’s glaciers were even more greatly reduced and seas were 30 to 130+ feet higher than they are presently.

Unfortunately, what the building global heat and currently very high greenhouse gas heat forcing means is that the Earth System will continue to accumulate warmth for some time. And as this happens more and more glaciers — both in Greenland and Antarctica — are going to destabilize, speed up, and contribute increasing melt volumes to the world ocean. Eliminating greenhouse gas emissions at this time and pushing to return to atmospheric levels in ranges below 350 ppm CO2 is therefore absolutely necessary if we are to have much hope of preventing ever-worsening rates of glacier destabilization and related contributions to sea level rise.

Links:

Collapsing Greenland Glacier Could Raise Seas by Half a Meter

Fast retreat of Zachariæ Isstrøm, northeast Greenland

Once Stable Glacier Facing Melt

NASA Science Missions — Oceans Melting Greenland (OMG)

Greenland Just Opened a Major New Floodgate to the Ocean

Livescience

Pliocene Climate

Miocene Climate

Departures in Pliocene Sea Level Record

Greenland Weather Underground

Hat tip to Todaysguestis

Hat tip to Colorado Bob

Hat tip to Ryan in New England

159 Comments

by robertscribbler on November 13, 2015 • Permalink

Posted in Climate Change

Tagged climate change, glacial melt, global warming, Human Hothouse, human warming, melt, Melting Greenland, OMG, sea level rise, Zachariæ Isstrøm

Posted by robertscribbler on November 13, 2015

https://robertscribbler.wordpress.com/2015/11/13/11038/

Greenland’s Late August Rain Over Melt Ponds is a Glacial Outburst Flood Hazard

Glacial melt ponding on steep ice faces. Above freezing temperatures for an extended period. Storms delivering rainfall to the glacier surface.

These three events are a bad combination and one that, until recently, we’ve never seen before for Greenland. It is a set of circumstances directly arising from a human-driven warming of the great ice sheet. And it is one that risks a highly violent and energetic event in which melt ponds over-top and glaciers are flushed and ripped apart by surges of water rushing for scores of miles over and through the ice sheet. Major melt pulse events called glacier outburst floods that can result in catastrophically large volumes of water and broken ice chunks issuing from the towering, melting glaciers of Greenland and Antarctica.

It’s a risk we face now, as the circumstances driving the risk of such an event are present today.

Rain over Ice on August 21, 2014

Over the past four days a high amplitude wave in the Jet Stream and coordinate domes of high pressure over Greenland have delivered well above average temperatures for the great Northern Hemisphere ice sheet. Near and just to the east of the Jakobshavn glacier on the West Coast of Greenland, temperatures have ranged between 5 and 10 degrees Celsius above average.

(GFS temperature and rainfall analysis for Greenland on August 21, 2014. Note the above freezing temperatures and rainfall over the region of the Jacobshavn Glacier for today. Image source: University of Maine’s Climate Reanalyzer.)

What this means is a persistence of average temperatures in the range of 34-40 degrees (F) over large sections of Greenland’s Jakobshavn glacier. Melt level readings over a region that has now experienced ongoing surface ponding for more than 60 days.

But these warm temperatures, providing yet more heat forcing to melt the ice, aren’t the only extreme weather factor for the Jakobshavn glacier today. For today has brought with it a warm, wet over-riding airmass emerging from Baffin Bay and the Atlantic Ocean to the south. The warm air, coming into contact with the cooler glacier air is condensing and disgorging a series of rainstorms, dumping above-freezing water into the Jakobshavn’s already swelling pools.

Some of these effects are directly visible in the LANCE MODIS satellite imagery provided by NASA.

Glacial melt ponds are indicated in the satellite shot below by light-to-dark blue splotches on the glacier surface. Shallow surface melt ponding and pooling is indicated by a thin skein of light blue. In the left frame below, you can see the extensive and large melt ponds in the region of the Jakobshavn Glacier on August 18, 2014. For reference, the largest of these ponds are between 2 and 4 kilometers across. Also note the pale blue color of the ice near the larger ponds, indicating extensive smaller ponds in the region.

In the right frame, we have today’s LANCE-MODIS satellite shot. You will note that the entire frame is covered by cloud but that you can still see the blue undertone of the melting glacier below the rain-bearing clouds.

(LANCE MODIS satellite shot of the Jakobshavn Glacier on August 18 [left frame] and August 20 [right frame]. Note the widespread melt ponds and blue ice indicating smaller ponds over the glacier structure. Image source: LANCE MODIS.)

Assessing Glacial Outburst Flood Risk

Some day, as Greenland continues to warm under the human heat forcing and as more hot air invasions ride up over the ice sheet, a period of warmth followed by rainstorms may well set off a major outburst flood event. The water content in melt ponds over the glacier may well be far greater than what we see now and a series of over topping events, starting higher on the ice sheet and magnifying toward the ice sheet base, would set of a chain of events leading to such a flood.

Risks for this kind of event today may well be moderate to low. The glaciers at this point are craggy and much of the flood waters shunt through holes in the ice to water pockets or to the glacier base. But eventually, as the glacier contains more water through subsequent years of melt, flooding and damming will be more prevalent throughout the ice sheet. And so risks will likely be on the rise.

Other than similar events occurring in the Himilayas, we don’t really have much of a context by which to judge risk for large Greenland outburst flood events. We do know that melt ponding is now quite extensive in this region and we do know that the glacier itself is rather unstable — moving with rapid speed toward the ocean and containing pockets of melted water from past melt pond formation over the last two decades.

For today, I’m pointing out the current rainfall over ice and melt ponding event as part of a larger and dangerous trend, one that is likely to play a primary role in the pace and violence of Greenland melt going forward.

(Photograph of a zodiac on the surface of one of Greenland’s very large melt ponds. Image source: Earth Observatory.)

Links:

University of Maine’s Climate Reanalyzer

LANCE MODIS

The Glacial Megaflood

168 Comments

by robertscribbler on August 21, 2014 • Permalink

Posted in Climate Change

Tagged basal melt, climate change, environment, extreme weather, glacial megaflood, glacier outburst flood, glacier outburst flood risk, global warming, Greenland ice sheet, greenland melt, greenland melt ponds, ice dam, melt, rain over ice sheets, record Greenland melt, science, surface melt, weather

Posted by robertscribbler on August 21, 2014

https://robertscribbler.wordpress.com/2014/08/21/greenlands-late-august-rain-over-melt-ponds-is-a-glacial-outburst-flood-hazard/

Arctic Sea Ice Loss Goes Vertical: Area the Size of Nevada Gone in One Day

The white, reflective barrier protecting our northern polar region from the heat-amplifying effects of human-caused warming took a severe blow today. The National Snow and Ice Data Center’s sea ice area measure essentially fell off a cliff as values plummeted by more than 286,000 square kilometers. That’s an area of ice the size of Nevada lost in a single 24 hour period. A state-sized region flipping from white, reflective, cooling ice, to dark, heat-absorptive water.

(Most recent day’s sea ice area measure shows vertical drop for June 2nd and a near vertical drop for June 3rd. Updated graph shows June 3, 2014 area measures tied with 2011 and 2012 for record low daily levels. Data source: Cryosphere Today/NSIDC. Image source: Pogoda i Klimat.)

Overall, the sprawl of sea ice fell to 9,984,000 square kilometers or a negative 907,000 square kilometer anomaly vs the already low 1979 to 2008 mean. The fall was rapid enough to bring sea ice area to within striking distance of new record lows for the date. Should the nose-dive continue for just one more day, the measure’s lower range will be shattered.

Arctic Still Warm as Extra Heat Goes to Work on Ice

Since May, weather conditions in the Arctic above the 66.5 degrees north Latitude line have remained somewhat warmer than usual. GFS averages have ranged from +1.5 to -0.3 C when compared to the, already warm, 1979 to 2000 average. And, in general, values have typically hovered in the +0.5 C range for the entire Arctic.

This temperature anomaly range is, however, a major fall from the extreme polar amplification we saw this winter on the order of +4 to +6 C above ‘normal’ temperatures during the months of January and February of 2014. It is the same relative winter-to-summer draw-down in anomalies we would expect come summer as the heat overburden goes to work doing the physical heavy lifting of ice melt rather than simply warming the air. In essence, as atmospheric and ocean temperatures approach the 28 F melt-freeze line of sea ice, energy, instead, is dumped more and more into ice melt. So though Summer is still quite a bit warmer than Winter in the Arctic, the pace of atmospheric warming in the winter is much greater so long as temperatures remain below ice-melt thresholds.

Heat Delivery Mechanisms: How Polar Amplification Melts Sea Ice

Extra dangerous and amplifying Arctic heat comes from many sources. Not only is the atmosphere over the Arctic more heavily burdened with heat-capturing gasses than the rest of the planet (currently at about 405.5 ppm CO2 and 1910 ppb methane as measured at NOAA’s Barrow Alaska station), high amplitude jet stream waves continue to deliver heat in the form of southerly warm wind invasions even as the ocean upon which the thinning ice rests draws ever more energy from an immense volume of warming water. Expanding holes in the ice, a darker, greener, Arctic environment, a rain of soot from massive wildfires burning at the Arctic’s gates — all contribute to overall warming in the Arctic system.

How this heat is delivered to the sea ice can take many forms. The first, and most obvious, is through direct solar heating of the ice itself. Such insolation heating requires both clear skies and warm air temperatures for greatest impact. In these ideal conditions, melt ponds can proliferate, greatly reducing sea ice albedo and further weakening ice for large melts later in the season. And recent studies suggest that widespread melt pond formation played a key role in both of the record melt seasons of 2007 and 2012.

(Thin ice over Hudson Bay, Canada on June 2 takes on the characteristic blue tint indicative of melt pond formation. During late spring of 2014, melt pond formation was relegated to the ice edge, primarily due to widespread cloud formation over the Arctic Ocean. Image source: LANCE MODIS.)

But for 2014, melt pond formation has been relegated to the ice edge boundary along the fast ice near Russia, in regions of the Canadian Arctic Archipelago, and in Hudson Bay. Large areas of cloud cover have persisted throughout the Arctic preventing a much more widespread occurrence of melt ponds. This high degree of cloudiness is likely due to the changing Arctic itself where increasing encounters between hot and cold are veritable cloud and mist generating machines. Such changes bear out in paleoclimate observations where proxy values show a more ice free Arctic is a much cloudier Arctic.

So if clouds interrupt solar insolation in a melting Arctic, then what other mechanisms go to work to deliver heat to the ice?

Weather Systems, Warming Lands and Waters

‘Fate,’ as the saying goes, ‘is not without its sense of irony.’ For water in all forms, including the low-lying clouds which are fogs and mists, is likely to play an ever-increasing role in Arctic melt. These emerging heat delivery mechanisms can simply be summed up as follows: warm wet winds, warm water upwelling, and warm rivers.

Warm Wet Winds blow from south to north and increasingly invade the Arctic as tundra melts and sea ice retreats. As summer temperatures at the Arctic boundary increase due to human forcings and related amplifying feedbacks, these warm, southerly gusts bear with them an ever-increasing moisture content. And since water has 4 times the heat capacity of air, winds laden with higher volumes of moisture carry much more heat to melt ice than the drier, colder winds of yore. When such winds contact the ice, a form of condensation mist is wrung out of the air due to temperature differential. The mist directly contacts the ice and delivers its x4 heat capacity to the ice surface. It’s a phenomena that many coastal residents in the northeastern US are well familiar with — something they call snow-eating fog.

During late spring of 2014, warm, wet winds were particularly prevalent in the region of the Bering and Chukchi Seas. These winds weren’t much warmer than sea ice freezing temperatures — ranging from 28 to 40 degrees F. But they picked up moisture in a large south to north synoptic pattern, dredging up heat and water from the temperate Pacific to dump it on the Arctic sea ice. The result was great gusts of mists and fogs eating away at the ice edge week-after-week.

In the above satellite image sequence (LANCE MODIS), we can see the drastic effects of prevalent warm winds. The top image is from April 25 of 2014, the bottom from June 2nd. In the top frame we can see the beginnings of mist and cloud formation at the ice edge along the path of persistent south to north wind flow. By June 2nd, this warm wind pattern has melted most of the Bering and Chukchi sea ice even as it intensified to a misty, cloudy maelstrom chewing away at the ice edge.

A more intense kind of a warm wind forcing can come in the form of a warm storm. These storms typically emerge from the south carrying with them a high degree of heat and moisture. A combination of rain, strong winds and increased wave action over sea ice can have a severe effect during a warm storm as was seen during the Great Arctic Cyclone of 2012. Such storms are likely to become more prevalent as the Arctic continues to heat up. And these systems can also generate a kind of warm water upwelling that eats away at the ice from below.

Warm Water Upwelling is an especially powerful force to melt ice that sits on a warming ocean, particularly when the ice is as thin, broken and mobile as we see in the Arctic today.

Impacts from warming and upwelling deep ocean waters have been both extraordinary and increasingly visible to major glacial systems in Greenland and West Antarctica where numerous ice sheets have begun an irreversible plunge toward the oceans.

In the Arctic, heat typically pools in deeper layers and at the near-shore below-surface boundary along the continental shelf. The ice rests in a zone of colder water at the surface. Atmospheric patterns such as persistent and strong high and low pressure systems can occasionally tap this deeper water heat through a mechanism known as Ekman pumping.

The way this works is that a large-scale swirl of air creates a kind of suction effect on the sea surface. In cyclonic storms, Ekman pumping causes upwelling to occur at the center of the storm and down-welling to occur at the edges. In high pressure systems, upwelling occurs along the edges while down-welling occurs at the center.

(Illustration of Ekman transport is cyclonic [storm] and anticyclonic [high pressure] systems. Image source: MIT.)

The effect this has on sea ice is that storms will tend to spread the ice out and thin it at their centers while high pressure systems will tend to pull the ice edge in and concentrate the ice. In addition, the upwelling at the edges of the anticyclone can add melt stress, especially in more shallow coastal basins, even as melt stress is added along storm paths in which warmer waters may have ventured closer to the ice bottom.

During the last week, a persistent high pressure system formed over the Beaufort Sea. It sat opposite a set of cyclones that formed near the Kara. The anticyclonic pattern of the high drew in ice from land-fast moorings in the East Siberian Sea even as warm upwelling and loss of albedo generated warmer surface temperatures in an expanding polynya zone — pumping out a burst of ice-eating mists. The anticyclone expanded into the Laptev where a similar edge draw and surface warming effect was visible even as the wind patterns between anticyclone and cyclone converged to amplify the northward retreat of ice.

In the top LANCE MODIS image frame we see East Siberian and Laptev seas already suffering ice loss and break-up due to a series of warm wind outbursts from the Asian continent on May 15 of this spring. In the bottom frame, we see today’s sea ice coverage dramatically reduced after a week of extreme ice damage due to anticyclonic recession and related edge upwelling.

As a result, both Laptev Sea ice and East Siberian Sea ice are well into record lowest ranges.

Warm Rivers also typically provide a strong pulse of heat to the Arctic through spring and into summer. As the Arctic lands thaw and the large continents warm, water flows from thawed rivers increase. In recent years, Jet Stream wave amplification has combined with warming temperatures in the region of 55 to 75 North Latitude to increase storminess and rainfall intensity. As a result, higher volumes of warmed waters flood north into what was once the ice sanctuary of the Arctic Basin. The pulse of water is generally enough to disintegrate land-fast ice and speed the ice melt further offshore.

Though large warm water pulses are not yet visible, regions to watch for 2014 will be the Mackenzie Delta and the mouths of the Kolyma, Lena, Yenisey, and Ob rivers. Major rainfall events in Siberia have been ongoing over the past week and will likely generate increased volumes of warm water flow for the Lena and Yenisey rivers particularly.

It is also worth noting that much warmer than average conditions have spread over the Mackenzie and Ob river basins.

Forecast Shows High Rate of Melt Likely

Today’s weather shows a continued building of the high pressure ridge over the Beaufort with GFS model forecasts predicting the ridge will remain in place over at least the next seven days. Persistence of this ridge pattern will continue to draw the ice in from the East Siberian and Laptev Seas even as warm winds over the Chukchi are reinforced. Sea ice totals may further be drawn down from rapid melt proceeding in both Hudson and Baffin Bay. Melt in these areas has lagged behind the larger Arctic somewhat, so current near record low totals are yet higher than they would otherwise be.

(107 hour GFS Model temperature forecast. Image source: University of Maine.)

Meanwhile, model runs show the Arctic steadily devolving into a kind of melt soup where atmospheric temperatures push into an above-freezing range for sea ice over the majority of the Arctic even as shore regions of Yakutia and the Mackenzie Delta are forecast to see temperatures in the mid 60s and 70s. These readings are in the daily range of +0.3 to +1.9 C above the 1979 to 2000 average for the entire area above the Arctic Circle and are predicted to hit local spikes from +4 to +18 C.

It should go without saying that a 70 degree reading in early June on the shores of the East Siberian Sea in the high Arctic is a clear sign of human-caused climate change gone nuts. And we are likely to see these and higher readings as spring proceeds into summer.

So though general cloudiness over the Arctic may continue to suppress melt pond formation, there likely remains enough heat baked-in to keep testing new record lows for sea ice. Even under cloud cover, dangers to the sea ice abound in the form of warm winds, warm storms, warm water upwelling, and a growing heat pulse from warming Arctic rivers. Amplifying heat and a growing number of ways in which that heat can be transferred to ice creates an ever-expanding risk for ice free conditions. Under such a regime, unexpected and extreme events are increasingly likely.

* * * *

UPDATE: According to reports from NSIDC and Cryosphere Today, negative Arctic sea ice area anomaly for the date grew to 988,000 square kilometers below the average for June 3rd. This represents an additional loss of 179,000 square kilometers, which is larger than the combined land masses of the UK and Croatia (or roughly the size of the state of Missouri). This most recent plunge pushes 2014 sea ice into record low range as it essentially ties values for both 2011 and 2012 on this date. Any single day loss greater than 120,000 square kilometers for tomorrow will extend 2014 losses into all-time record low range.

In total, the plunge over June 2-3 represents 465,000 square kilometers or an area larger than the combined regions of California and Maryland. It is worth noting that weekly losses in the range of 500,000 square kilometers are considered extreme. We have instead witnessed a near 500,000 square kilometer loss in just two days.

(Thin ice visible over broad stretches of the Arctic. Image source: Uni-Bremen.)

As an additional note, it’s worth sharing the observation that while high pressure systems and warm winds have placed extreme melt pressure and caused the ice edge to rapidly recede in the Chukchi, East Siberian and Laptev seas, ongoing cyclonic action in a rough triangle from the North Pole to Greenland to the Kara Sea has resulted in a great breaking, thinning and dispersal of ice in this region. The cyclones in the area, though weak, have generated enough force to greatly disperse the ice and, perhaps, to access warmer waters just below the ice in sections where ice has repeatedly expanded and retracted over recent months. Large patches of sea ice concentration of less than 75% in this zone make it very vulnerable to any additional heat and melt forcing.

So it appears the Arctic is split between weather forces — with cyclones dominating the sea ice between the North Pole, the Kara, and the coasts of Greenland and with high pressure systems dominating the Beaufort and the Laptev. Forecast higher temperatures injected into what is already a strong melt regime continue to generate high risk for rapid melt.

Links:

Cryosphere Today/NSIDC

by robertscribbler on June 3, 2014 • Permalink

Posted in Climate Change

Tagged Arctic sea ice 2014, arctic sea ice melt, climate change, environment, extreme weather, global warming, melt, melting the size of Nevada in one day, record melt, science, sea ice, sea ice melt, weather

Posted by robertscribbler on June 3, 2014

https://robertscribbler.wordpress.com/2014/06/03/arctic-sea-ice-loss-goes-vertical-area-the-size-of-nevada-gone-in-one-day/

Arctic Heat Drives Sea Ice Back Into Record Low Territory At Top of Melt Season

(Record low sea ice cover on March 10, 2014 a time that typically features sea ice maximum. Note that all basins show sea ice area and extent below the, already lower than normal, 1979-2000 base-line. Image source: Climate Change Institute.)

Abnormal, warm southerly winds at the lower and upper levels. More large heat pulses driven by high amplitude Jet Stream waves. Tropical heat launching into the Arctic Stratosphere over the Himalayas. Warm water upwelling from the rapidly heating ocean depths.

All conditions that continue to place the Arctic sea ice under a state of constant siege — winter and summer. All again doing their dangerous work in pushing the now critically weakened ice, once more to record low levels.

Under this state of ongoing assault, regions near Svalbard fell into rapid retreat as floes fractured over warming waters in the Bering Sea and west of Greenland. The result is the lowest measure of winter time sea ice area ever seen in any record for this day since Arctic observation began. Yet one more passing milestone in the vicious and rapid progression of human-caused climate change.

2011 Records Fall

According to reports from NSIDC and Cryosphere Today, Arctic sea ice area dropped to a record low of 12.95 million square kilometers on March 10 of 2014. It is a measure more than 2 million square kilometers, or an area roughly the size of Greenland, smaller than that seen during the late 1970s and breaking the previous record low, set just three years ago, by 150,000 square kilometers. Sea ice extent, meanwhile, had fallen to 14.5 million square kilometers, a measure roughly tied with the previous record low set in 2011 and also about 2 million square kilometers below area values seen during the late 1970s.

It is worth noting that the trend lines for both sea ice extent and area are well below previous trends for record low years 2007 (green below) and 2012 (pink below).

(March 10 Sea Ice Area showing record low for the day. Image source: Pogoda i Klimat. Data Source: Cryosphere Today.)

Melt Hot Spots: Ocean Zones Near Svalbard and Greenland

With the Aqua Satellite again cresting the Arctic, we can peer down through cloud and ice to see dark, open waters peeking through kilometer-wide cracks or dominating entire ocean zones during a very anemic peak freeze. With recent days bringing average Arctic temperatures in the range of 2.5 to 4.5 degrees Celsius above normal and with local spikes in the +20 degrees C above normal range, areas of visible retreat and fragility abound.

These heat spikes combined with strong southerly winds near Svalbard to drive a rapid, far-north, retreat of ice floes on March 9-11 into zones that previously saw open ocean only during summer time. This far northward invasion of dark, open water is the primary culprit of the new record low:

(Open ocean north and west of Svalbard on March 11, 2014. It is worth noting that Svalbard is about 600 miles from the North Pole. The Current sea ice edge, during a time when ice extent should be at its maximum, is now just 500 miles from the North Pole. Image source: Lance-Modis.)

A large region of northern Baffin Bay near Northwest Greenland and the Canadian Arctic Archipelago also showed extensive melt and open ocean zones during recent days.

Over past decade, this region has shown increasing susceptibility to warm ocean water upwelling near the Nares Strait with winter-time melting of northern extremities in Baffin Bay. But this year’s melt was particularly strong. An event that coincided with sea-bed earthquakes and anomalously high methane levels (1950 ppb+) in the region through mid-to-late February. It is possible that upwelling is both driven by warm water currents now filling up the Baffin deep water zone and by the somewhat energetic out-gassing of sea bed methane through faults and seeps.

It is worth noting that evidence of these seeps is based on satellite observation and very little in the way of comprehensive seabed methane assessment has been completed by the global scientific community, a gap in understanding that may well come back to haunt us as human-caused warming continues to put increased heat pressure on both deep and shallow ocean carbon stores.

(Fingerprints of warm water upwelling, sea-bed methane release? Extensive open water, cracked ice in North Baffin Bay, Nares Strait region during height of sea ice extent, 2014. Image source: Lance Modis.)

Heightened risk for record low year, total meltdown

The current record low status for end winter sea ice and the approach of El Nino, which tends to add heat to the European and Asian continents, results in an increased risk that new record lows for sea ice area, extent and volume may be reached by end of summer 2014. Both warm air and water flushing in from the continents have been implicated in large sea ice retreats during recent years and a rapid heating of the large land mass over Arctic Europe and Asia, along with a simultaneous warming of Alaska, should El Nino progress, may amplify both continental heat build up and heat transfer through river outflow into the Arctic Ocean Basin.

In addition, high temperature anomalies during late winter to early spring continue to suppress sea ice recovery late season. The result is that more open ocean is now available to absorb energy from the rising sun or to deliver that energy in the form of waves and currents to the greatly diminished ice pack. The one saving grace, if it can be viewed as such, is a minor, though likely temporary rebound in sea ice volume extending from late last year, likely bringing volume values into the range of 3rd or 4th lowest on record for March.

It is also worth considering that sea ice area trends show an ever-increasing possibility of a record melt year with melt rates similar to 2007, 2011 or 2012 enough to bring 2014 to new record lows.

(Sea ice area projections based on past trends. It is worth noting that the melt season has lengthened by nearly a month since 1979, the result being increasing volumes of ice lost from end of freeze to end of melt. Image source: Jim Pettit. Data Source: NSIDC.)

In any case, this combination of conditions generates a high risk of sea ice reaching new record lows in sea ice area, volume and/or extent come end of summer 2014 (60%). This prediction finds its basis in observed records of past melt seasons and in the fact that very few days remain for a potential late-season uptick in sea ice. If record low values hold and a late season rebound does not occur, it is worth considering this simple fact: each time sea ice reached a new record low maximum sea ice area since 2005, a new record area melt was achieved by end of summer. That said, not achieving a record low maximum is no guarantee of safety, as 2012 so starkly proved.

It is also worth considering that sea ice may be very close to tipping points and once thinned beyond a certain threshold will be unable maintain integrity. In such an event, warm, dark, increasingly mobile ocean waters eventually overwhelm an ice pack fighting for survival. We may well have seen the beginning of such a consequence during 2012 when powerful and energetic storms that would usually result in sea ice retention only served to hasten record losses. A warning that there are fewer and fewer conditions favoring summer ice retention as the Arctic energy balance is ever more forcibly shoved toward melt.

Given these potentials — the high likelihood for record low area at maximum, the ever-lengthening melt season, and the increasing fragility of ice come end-summer — it is worth considering the unexpected worst case: total sea ice loss or near total ice loss (less than 1 million square kilometers area) by end of summer 2014. At this point, given record low area conditions late in the freeze season, we will assess a slight uptick of total ice loss risk over the previous year from 10 to 15 percent — a somewhat increased risk that sea ice values reach near ice free levels during a catastrophic melt this summer (15%).

If an observed start to the melt season begins early and if melt rates rapidly steepen, we will likely reassess both the likelihood of new records at minimum and a potential ice-free end summer state in the face of increased risks. At this point, both measures are low confidence estimates based on trends analysis, observation of current unprecedented Arctic warmth, and continued fragile ice state conditions.

UPDATE:

March 11 Arctic sea ice area values showed continued decline into record low territory. March 10 to 11 area losses, according to Cryosphere Today, extended an additional 70,000 square kilometers pushing the value down to 12.88 million square kilometers over the entire Arctic. This level is about 130,000 square kilometers below the previous record low value for today set in 2011 at 13.1 million square kilometers.

Abnormal atmospheric warmth over the regions most affected including north and east of Svalbard, Frans Joseph Land, the Kara Sea, a large region of Russia near Dickson, and in the region of the Nares Strait continued to provide melt pressure driving the most recent record low.

Links:

NSIDC

Climate Change Institute

by robertscribbler on March 12, 2014 • Permalink

Posted in Climate Change

Tagged arctic sea ice, arctic sea ice melt, climate change, environment, global warming, human caused climate change, human warming, ice-free Arctic, melt, record low, record low sea ice maximum, science, sea ice melt

Posted by robertscribbler on March 12, 2014

https://robertscribbler.wordpress.com/2014/03/12/arctic-heat-drives-sea-ice-back-into-record-low-territory-at-top-of-melt-season/

Arctic Heat Wave Sets off Hottest Ever Winter-Time Temperatures, Major Melt, Disasters for Coastal and Interior Alaska

Major melt in the midst of winter. Doesn’t sound quite right, does it? We tend to think of winter as the time of freezing, as the time of ice accumulation. Not the time of melt and thaw.

Now try this — major melt in Alaska in the midst of winter. Average temperatures 40 degrees hotter than normal in the midst of winter. Rainfall over snow and ice causing avalanches, major road blockages and ice dams to rivers in the midst of winter.

In this instance we have been transported from the somewhat odd into a reality that is completely outside of our previously ‘normal’ context. In this instance we are transported to a time that may well seem like the beginning of the end of the age of ice on planet Earth.

And yet this is exactly what is happening: one of the coldest regions on the planet is experiencing melt and related record heat in January.

For the state of Alaska, the consequences are a strange and freakish winter heat wave, one that features the extreme temperatures mentioned above. For the city of Valdez, as we shall see below, the situation is far more stark.

(Massive Avalanche set off by rainfall, winter warmth, cutting off Richardson Highway to Valdez Alaska and forming a dangerous ice dam of the ironically named Keystone Canyon’s Lowe River. Image source: Alaska Department of Transportation and Public Facilities.)

Hottest ever Winter-time Temperatures for Alaska

On Sunday, a collapse event that flooded the Arctic with heat and ripped the polar vortex in half began. A freakish high amplitude ridge in the Jet Stream that had been pumping warmth over Alaska and into the Arctic for ten months running strengthened. The result was that many regions throughout the state experienced their hottest temperatures ever recorded for that day, month, or season.

(Global Temperature Anomaly Data vs 1979-2000 mean with focus on Arctic for January 29. Note the extreme Arctic deviation of +5.58 degrees Celsius and the pool of 36+ F high temperature deviations still lingering over Alaska. Also note that global anomalies are +.32 C above the 1979-2000 mean which is, itself, about +.5 C above average temperatures during the 1880s, for a total of about +.82 globally. The above measure is an excellent illustration of both extreme polar amplification and very rapid warming coinciding with a strong negative Arctic Oscillation, related warm air influx, and polar vortex separation. Source: Climate Change Institute.)

According to reports from Weather Underground, Homer Alaska, for example, experienced an all time record high for the day of 55 degrees Fahrenheit, 4 degrees hotter than the previous all-time high set just a few years earlier. And Homer was just one of the many cities sitting in a broad region of extraordinary, 40 degree hotter than normal temperatures. A region extending from the interior to the southern and western coasts. Bolio Lake Range, about 100 miles south of Fairbanks in central Alaska, saw temperatures rocket to 60 degrees, just 2 degrees short of the all-time record high for any part of the state during January (the previous record high of 62 was set in Petersburg, nearly 700 miles to the south and east).

Typically colder high mountain regions also experienced record warmth for the day. A zone 10,600 feet above Fairbanks hit 32 degrees Fahrenheit on Sunday, the highest temperature ever measured for this region during any winter-time period from November through February.

Even before the most recent extreme Arctic temperature spike, January saw numerous powerful heat influxes for Alaska with Nome, Denali Park, Palmer, Homer, Alyseka, Seward, and Talkeetna each setting all-time record high temperatures during the month.

These records come on the back of a long period of rapidly increasing Alaskan heat stretching all the way back to the 1970s. In many cases, we are seeing all-time record highs broken with 5-10 year frequency. In the most extreme cases, these records fall again after only standing for 1-5 years.

Taken in this context, what we are seeing is the freakish continuation of an ongoing period of inexorable Arctic warming providing yet one more major insult to the Alaskan climate during the winter of 2013-2014.

Rain and Melt Sets off Major, Spring-like, Outflows From Streams and Rivers

The same anomalous Jet Stream pattern that has acted as a conveyer belt continuously transporting heat into the high north over Alaska has brought with it an almost endless series of rain events to coastal Alaska. Storm after storm, fueled by heat and high rates of evaporation over the northern Pacific, slammed into the Alaskan coastline, disgorging record levels of precipitation.

With temperatures freakishly high, mirroring conditions typically present during late spring or early summer, much of this precipitation fell in the form of rain. Valdez, Alaska, for example, has likely experienced its wettest January ever with rainfall measures just 1.35 inches short of the record on Sunday and a series of strong storms rushing into the city on Monday and Tuesday. Given the nearly endless train of storms lining up to sweep over Valdez, it is possible that its previous record of 15.18 inches for January could easily be surpassed by an inch or two at month-end.

The storms and cloudiness make it difficult to peer down and get a good view of what all this heat and rainfall is doing to the Alaskan snow and ice pack. But, for brief respite, on January 25th, just ahead of the most recent influx of rain and warmth, the clouds cleared, revealing the land and sea surface. And what we witness is extraordinary:

(Southern Coast of Alaska with major sediment outflow from snow and ice melt, record heat and rainfall in January 2014. Image source: Lance-Modis)

The entire southern coast of Alaska from Prince William Sound to Cook Inlet are visibly experiencing major snow and ice melt along with flooded streams and rivers flushing out a massive volume of sediment into the Gulf Alaska. Clearly visible in the satellite shot, the sediment now streaming into the ocean is more reminiscent of a major late spring flood event than anything that should be ongoing for Alaska in the midst of winter.

Yet here we are. A situation of continuous, never-before seen heat for Alaska during winter time bringing on a flooding thaw that is far, far too early.

Rainfall over Glaciers, Snow Pack Triggers Massive Avalanche that Cuts off Valdez

The constant assault of heat and record temperatures combined with an almost endless flow of moisture riding up from the Gulf of Alaska set off a devastating and freakish event near Valdez on Saturday. Severe and record rainfall over the mountain regions have continuously softened glacial ice and snow packs above this major Alaskan city. On Monday, the continuous insults of heat and water passed a critical threshold.

As the warm water filtered down through the colder snow and ice, the anchoring base was lubricated even as the capping snow grew heavily burdened with water. Eventually, the insults of heat and rainfall became too great and a major snow and ice slope system above the main road linking Valdez to mainland Alaska collapsed. The immense volume of snow and ice unleashed, spilling down to fill the base of Keystone Canyon, blocking both the Lowe River and the Richardson Highway running through it.

This snow and ice dam rose as high as 100 feet above the Canyon floor, causing the Lowe River to rapidly flood, inundating the already snow-and ice buried road under an expanding pool 20 to 25 feet deep and filled with ice-choked water.

You can see the massive avalanche-created ice dam and related road inundation in the video provided by akiwiguy below:

(video source: akiwiguy)

Warming-related rainfall events of the kind that has now cut Valdez off from the mainland are just one of the extraordinarily dangerous consequences of human-caused climate change. They are a phenomena linked to the massive glacial outburst flood that killed thousands in India this year together with other dangerous snow and ice melt events. Should such major heating and rainfall events impact Greenland and West Antarctica, the consequences could be even more extreme than what we are currently witnessing in Alaska.

Conditions in Context

In the context of our present extreme Jet Stream pattern that is setting off warmest-ever conditions for Alaska during January together with dangerous melt-outburst related events while at the same time periodically flushing Arctic air and extreme winter weather south into the United States, it is important to remember a few things. The first is that the Arctic is now experiencing never-before observed warmth with stunning frequency. Scientific papers now show that the Arctic is hotter than it has been for at least 44,000 years and possibly 120,000 years.

By comparison, the cold snaps, that could very well be seen as the death gasps of the Arctic we know, impacting the eastern US are relatively minor when put into this larger, more ominous context. Similar cold events were last seen about 20 years ago in the US. And so there is simply no comparison that can generate a rational equivalency between the, hottest in an age, Arctic temperatures and the, coldest in a few handfuls of years, temperatures in the Eastern US.

And if you’re one of those sensitive, perceptive souls who feels that the weather events you’re seeing, the extreme swings from very hot to somewhat cool temperatures, the extreme swings from drought to record rainfall, and the extreme events now accelerating the melting of the world’s ice and snow, are freakish, strange, and terrifyingly abnormal, then you are absolutely correct. Don’t let anyone, be they friends or family, or journalists in the media, tell you otherwise. There is reason for your discomfort and there is very serious cause for concern.

Links:

Colorado Bob’s Climate Feed

Weather Underground

NASA: Lance-Modis

Alaska Department of Transportation and Public Facilities

Climate Change Institute

Alaska All Time High For This Date, Warmer than Alabama

The Glacial Megaflood

Arctic Experiencing Hottest Temperatures in at Least 44,000 Years

Arctic Heat Wave to Rip Polar Vortex in Half

akiwiguy

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by robertscribbler on January 28, 2014 • Permalink

Posted in Climate Change

Posted by robertscribbler on January 28, 2014

https://robertscribbler.wordpress.com/2014/01/28/arctic-heat-wave-sets-off-hottest-ever-winter-time-temperatures-major-melt-disasters-for-coastal-and-interior-alaska/

New Study Finds Arctic Experiencing Hottest Temps in Nearly 120,000 Years; Lead Author: All Baffin Ice Caps Set to ‘Eventually Disappear’

“All of Baffin Island is melting, and we expect all the ice caps to eventually disappear, even if there is no additional warming.” Gifford Miller, University of Colorado climate scientist and co-author of a recent scientific study entitled: Unprecedented recent summer warmth in Arctic Canada.

***

(Satellite shot of Baffin Island and surrounding Arctic environs in September of 2013. Image source: NASA)

Baffin Island is a frozen archipelago situated to the west of Greenland and to the north and east of Hudson Bay. Like Greenland, it straddles the 70th parallel as well as the Arctic Circle. And like Greenland it is showing increasing signs of unprecedented warmth and melting. Though Baffin does not boast the massive ice caps of Greenland, large glaciers still cover much of its lands and fjords. The remaining areas are littered with small brown and green grasses and shrubs struggling up from rocky outcrops or from wide ranges of the now thawing tundra.

Like so many other places in our world, Baffin Island is a place where the deep past is coming into collision with a rapid and radical transition. A transition caused by humans and their endlessly increasing use of carbon-based fuels.

Over the past 150 years humans have released enough carbon dioxide into the atmosphere to achieve a global concentration of this gas that, by spring of 2013, exceeded 400 parts per million. This unprecedented high level, a level nearly 50% higher than the global concentration 150 years ago, was last seen on the Earth around 3.6 million years ago. And if past climate states are any true guide, then the vast volumes of greenhouse gasses already released into the atmosphere by humans are enough to melt all the ice on Baffin and at least half the ice on Greenland. It is this understanding of the effects of greenhouse gasses on past climates and ice states that prompted Miller to claim we’ve already released enough CO2 to melt the remaining ice on an isle that has been locked in freezing conditions since the dawn of humankind.

A Message From Earth’s Thawing Tundra

On Baffin and all over the high Arctic, vast swaths of the world’s tundra are rapidly being liberated from an eons-old ice cap. Scientists Gifford H. Miller, Scott J. Lehman, Kurt A. Refsnider, John R. Southon, and Yafang Zhong journeyed to Baffin’s thawing ice with a key question in mind: ‘When was the last time this region of the far north thawed?’ They came armed with the latest scientific tools and measures — tools that provided radio-carbon dating to determine the age of the most recently thawed plants. What the study found was chilling. Many of the plants newly liberated by the thawing ice were at least 44,000 years old. Others were possibly as old as 120,000 years.

This new evidence shows that the heat wave the Arctic is now experiencing, a heat wave that has driven sea ice deeper and deeper into the high Arctic, a heat wave that is melting, on average, about 500 gigatons of ice from Greenland each year (and about 25 gigatons of ice from Baffin), a heat wave that is turning millions of square miles of tundra into a melting, carbon-rich soup is hotter than even the hottest period during the last 11,000 years. And it shows that the Arctic probably hasn’t experienced this much melting since the last inter-glacial period — the Eemian.

The more recent time marking a space from the end of the last ice age to the present day is known as the Holocene. It marks the most recent geological epoc. During the early and middle years of the Holocene, solar insolation — or the measured amount of radiation coming from the sun — was as much as 9% stronger. But, according to the recent paper, human greenhouse gas emissions have been enough to completely overwhelm even the peak Holocene heat effect of a 9% stronger Arctic sun experienced centuries and centuries ago:

“The key piece here is just how unprecedented the warming of Arctic Canada is,” Gifford Miller, a researcher at the University of Colorado, Boulder, said in a joint statement from the school and the publisher of the journal Geophysical Research Letters. “This study really says the warming we are seeing is outside any kind of known natural variability, and it has to be due to increased greenhouse gasses in the atmosphere.”

It’s amazing to think that humans have already set in effect levels of warmth unsurpassed in 44,000 years and, possibly, 120,000 years. This new information, in itself, is unprecedented. But don’t make the mistake of falling into the false and relative comfort of thinking we only need to worry about the climates of 120,000 years ago. We’re already passing that marker now. As mentioned above, we’ve already released enough greenhouse gasses to at least return Earth to climates not seen in 3.6 million years. In this respect, the Baffin Island study adds to research conducted at Lake El’gygytgyn showing that levels of CO2 comparable to those seen today resulted in Arctic temperatures 8 degrees Celsius hotter during the deep past.

Rapidly Changing Arctic to Liberate More Greenhouse Gasses

Sadly, it is Miller’s final statement, the one stating that all the ice on Baffin is bound to melt, no matter what, which bears the most weight in our current day. With coal plants still being constructed at a break-neck pace in India and China, and with human greenhouse gas emissions rising above 45 gigatons of CO2 equivalent each year, we would be lucky if the end level of melt only included the ice on Baffin combined with a large section of the ice over Greenland. Instead, we are rapidly forging along toward a CO2 level of 550 to 600 ppm which will almost certainly ensure a dangerous and rapid melting of all the remaining ice on Earth.

In addition, billions of tons of carbon in the form of methane and CO2 lay locked within the millions of square miles of thawing permafrost. Some of this methane and CO2 is already out-gassing, adding to the already dangerously high levels of human greenhouse gasses.

Over the past month, the Arctic saw major methane spikes in which atmospheric concentrations of this potent greenhouse gas reached nearly 2500 parts per billion, more than 650 parts per billion above the global average. And should the Arctic continue to warm we are more likely to see even larger spikes of both methane and CO2 further amplifying already unprecedented Arctic warmth.

Most likely, we are headed to at least the temperatures last seen during the Pliocene, in which global averages ranged 2-3 degrees Celsius hotter than the present and during which oceans were 25-75 feet higher. Unfortunately, these are the long-term consequences we have probably already locked in. But without rapid reductions in carbon emissions to near zero over the coming decades, we can expect far, far worse outcomes.

Links:

Unprecedented Recent Summer Warmth in Arctic Canada

Arctic Temperatures at 44,000 year High

NASA/Lance-Modis

The Eemian Interglacial

Latest Methane Data Provided by USGS and Methane Tracker

Accelerated Contributions of Canada’s Baffin and Byot Island Glaciers to Sea Level Rise Over The Past Half Century

18 Comments

by robertscribbler on November 5, 2013 • Permalink

Posted in Climate Change

Tagged amplifying feedbacks, Baffin Island, Baffin Study, climate change, extreme weather, feedbacks, global warming, human warming, melt, Pliocene, science, tundra melt, weather

Posted by robertscribbler on November 5, 2013

https://robertscribbler.wordpress.com/2013/11/05/new-study-finds-arctic-experiencing-hottest-temps-in-nearly-120000-years-lead-author-all-baffin-ice-caps-set-to-eventually-disappear/

Global Warming Rolls Climate Dice Yet Again: High Amplitude Jet Stream Wave Brings Late July Melt Surge to Greenland

The old cliche is that lightning never strikes twice in the same place. In weather and climate terms, natural variability makes it highly unlikely that record year will follow record year, even when a forcing, such as human global warming, tends to push in that direction.

In the context of Greenland, it was very unlikely that record melt on the order of around 700 gigatons of ice lost during 2012 would repeat in 2013. That said, even in a year like 2013, where climate attempts a return to the average trend line, it’s entirely clear that conditions are anything but normal.

Throughout late June and much of July, a downward dip in the Jet Stream dominated weather patterns over Greenland. Cold, Arctic air was locked over the massive island, pushing melt rates closer to ‘normal’ for a summer season. The term to use is definitely ‘closer,’ because even during weather conditions that would normally bring colder than average conditions to Greenland, warmth and melt were still above average.

Global warming adds a roll

A metaphor we can use to describe this phenomena of implied variability in a warming system is James Hansen’s climate dice. Imagine that a basic roll of a d10 gives us a typical weather pattern for Greenland. 1 on the dice represents record cold, 10 record warmth, 2 and 3 are colder than average, with 2 being near record lows and 3 being closer to average, 4, 5, 6 and 7 are average, 8 and 9 are hotter than average, and 10 is record heat.

This set of weather and climate possibilities is a basic representation of ‘normal’ for Greenland. But when we add in human climate change and global warming, we are essentially adding a new player to the mix, with its own set of dice. In this case, let’s add a 1d3 to the global warming hand. Now, with the extra dice roll for global warming, the potential for extreme hot, melting years just got far, far more likely and we begin to experience never seen before heat and melt events. But we still end up with colder than average years and normal years, just less of them.

The situation is probably worse than the simulation described above because on the typical 1 to 10 scale we can label 2012 about a 13 (with freakish never seen before record heat and melt) and 2013 through about July 26th a 7.1 — slightly hotter than average with ever so slightly above average melt.

The problem is that June and July were average when they should have been cold. I say this because a high amplitude wave in the Jet Stream flowed down over Greenland, pushing relatively colder air over the sea ice and into the freezer that is still Greenland. Such conditions usually push for colder than average Greenland temperatures and lower than average melt. This period of what should have been colder than average conditions instead resulted only in an abatement of record melt and a return to slightly above average melt.

Mangled Jet Stream switches back to ‘hot’

But now, even this brief respite appears to have evaporated. Over the past couple of weeks, the deep, cooler trough over Greenland eroded, weakening as warmer air pushed into southern Greenland. Now, the trough has completely reversed — becoming a ridge and somewhat mimicking the freakish conditions that occurred during 2012. So slightly above average melt conditions are now starting to swing back toward record melt conditions for this time of year.

You can see the large, high amplitude bulge riding from south to north, carrying air from the south-eastern US all the way north to Baffin Bay and southwestern Greenland, in the Jet Stream map for July 30th below:

(Image source: California Regional Weather Service)

This sudden Jet Stream switch brings back a weather pattern that caused such major melt conditions during summer of 2012 and such warm winter conditions for Greenland as 2012 turned to 2013. And the results, as far as ice melt goes, have been almost immediate. Earlier melt peaks at around 34% of the ice sheet during July were obliterated in one fell switch of atmospheric air flow that, once again, drew warm, temperate air into the Arctic.

Over the past two days, this extra warmth has increased Greenland melt area to above 40%, peaking at near 45% just a couple of days ago. This peak, though not as anomalous as the 90% + melt coverage experienced during early July of 2012, is still about 80% higher than the average melt peak observed for the period of 1981-2010 and more than double the average for melt in late July. It also puts Greenland further into above average melt year territory, possibly shifting the 2013 score from 7.1 to around 8.5.

You can see the melt coverages graph, provided by NSIDC, for the current year below:

(Image source: NSIDC)

The warm air pulse that drove these anomalously high late season melt rates in Greenland appears to have settled in for at least the time being. Temperatures along the Greenland coast range from the upper 30s to the lower 60s — quite warm for this time of year — while summit Greenland is experiencing warmer than average temperatures in the lower 20s (Fahrenheit).

Above average melt when it should have been cold

So what is freakish about 2013 when compared to 2012 is not that it matched a major melt event that will likely stand as a record for the next five years or so, but that in a year where weather conditions would have pushed Greenland to be mostly colder than normal, above average warmth and melt were still experienced. In this case, it becomes very clear that we are rolling with loaded climate dice or, as the illustration above shows, human global warming is adding its own wicked set of rolls.

Links:

California Regional Weather Service

NSIDC

James Hansen’s Climate Dice

Learn about Dark Snow

13 Comments

by robertscribbler on July 30, 2013 • Permalink

Posted in Climate Change

Tagged above average melt, climate change, climate dice, dark snow, environment, global warming, greenland, greenland melt, Greenland melting, James Hansen, melt, record melt, science, weather

Posted by robertscribbler on July 30, 2013

https://robertscribbler.wordpress.com/2013/07/30/global-warming-rolls-climate-dice-yet-again-high-amplitude-jet-stream-wave-brings-late-july-melt-surge-to-greenland/

Sudden Arctic Cyclone Churns Through Beaufort Sea Ice

Sudden Arctic Cyclone 2013 over Beaufort Sea. Image source: DMI

In a new incarnation of the Warm Storm event that has increasingly come to impact summer Arctic sea ice, a rapidly intensifying low pressure system formed Tuesday over the Beaufort, tracking directly through a large section of vulnerable ice and moving on toward the Canadian Archipelago. At its most intense the storm dropped to 977 millibars but has weakened slightly today to 980 millibars. The storm is expected to continue slowly weakening through today and tomorrow until finally fading by late Saturday or early Sunday.

Though strong, this storm is expected to be brief and is likely to not have the same impacts seen during the Great Arctic Cyclone of 2012. That storm approached the Arctic as an already well-developed system. Packing winds in excess of 60 miles per hour, it had the opportunity to rile a large section of open water and then fling waves as high as 10 feet up against the ice pack. Though this particular storm has hosted gale force winds, they have mostly blown parallel to the ice edge and did not have the same opportunity to develop a longer fetch over open water. It is also worth noting that the Great Arctic Cyclone lasted for about two weeks while this most recent Sudden Arctic Cyclone is likely to last for only about four to five days. So ongoing effects are likely to be limited.

All that said, this storm should have some impact. Already, an increasing number of slats of open water are visible through large sections of the Beaufort and the ice edge appears to have been torn at like a large swatch of tissue paper might act when forcibly twisted. The ice this year is particularly thin and slushy, making it subject to much more rapid motion and deformation. So we are already seeing such effects.

The below image shows a section of central Beaufort sea ice just after the storm center passed. Note the cracked and more diffuse condition of the ice.

Sea ice traumatized by Sudden Arctic Cyclone at 80N and 150W. Image source: NASA

In addition to the impacts described above, warmer air and constant sunlight over the Beaufort have likely provided a number of reservoirs of heat energy for the storm to tap to melt and thin the ice. Cyclonic pumping will be able to dredge warmer, saltier waters from the bottom layer even as surface churning will mix both ice and water warmed by these cyclonic forces. Brine channels within the ice are more likely to activate now that summer has had the opportunity to soften up the ice, pushing an increasing number of patches above the critical -5 C threshold.

CICE model runs do show a substantial thinning of Beaufort sea ice over the next few days even as the thick sea ice remaining near the Canadian Archipelago is both shoved into narrow island channels and ablated toward the Fram Strait between Greenland and Svalbard. Note the shift of light blue to dark blue, and yellow and red to green in many regions indicating significant predicted thinning in response to storm conditions. The two meter ice line is seen to rapidly retreat into the Beaufort from near the Canada/Alaska coast and also from the Chukchi, East Siberian, and Laptev Seas. Meanwhile, the four meter ice line is slammed directly against the Canadian Archipelago as thicker ice is slammed against shores or jammed into the island channels:

CICE model run. Image source: US Navy.

In summary, we can expect these effects from this, rather strong, storm. Not likely to be as pronounced as GAC 2012 nor as ongoing as PAC 2013 (whose scars are still visible in the large region of melt in a wide triangle from the Laptev toward the North Pole). But this Sudden Arctic Cyclone will certainly leave its own mark on the 2013 melt season.

3 Comments

by robertscribbler on July 25, 2013 • Permalink

Posted in Climate Change

Tagged arctic sea ice, Climate, climate change, environment, global warming, greenhouse gasses, human warming, melt, science, sea ice, weather

Posted by robertscribbler on July 25, 2013

https://robertscribbler.wordpress.com/2013/07/25/sudden-arctic-cyclone-churns-through-beaufort-sea-ice/

First Named Arctic Cyclone to Deliver Powerful Blow to Sea Ice?

The weather models are all in agreement, an Arctic Cyclone is predicted to form over the Beaufort and Chukchi Seas tonight and tomorrow, then strengthen to around 980 millibars as it churns through a section of thin and broken sea ice. The storm is predicted to last at least until Saturday and is expected to deliver gale force winds over a broad swath of thinning sea ice throughout much of its duration.

Gale force winds predicted for Beaufort, Chukchi and East Siberia Seas.

(Image source: Arctic Weather Maps)

The fact that this particular storm is forming in late summer is some cause for concern. The sea ice has been subjected to above freezing temperatures for some time. Melt ponds have increasingly formed over much of the Arctic and, since late June, most of the precipitation falling on the Arctic has been in the form of rain. The central ice pack is in complete chaos, with extensive thinning and fracturing surrounding a wide arc near the North Pole and a broad melt triangle full of broken ice and patches of open water extending far into the Laptev Sea. Further, the long duration of sunlight falling on the ice surface and penetrating into the ocean layer just beneath has likely warmed waters below the cold, fresh layer near the ice.

As the storm passes, its strong winds and cyclonic circulation have the potential to dredge up this warmer water and bring it in contact with the ice bottom. Such action can rapidly enhance melt, as we saw during the Great Arctic Cyclone of 2012. Since the brine channels are all mostly activated (with much ice in the region now above -5 degrees Celsius) Cyclonic pumping during storm events like this one can transport sea water directly through the ice to increase the size of melt ponds, to break, or to even disintegrate ice flows.

It is important to add the caveat that this particular storm in not predicted to be quite as long or as strong as the Great Arctic Cyclone of 2012 which, in its first week, coincided with a loss of 800,000 square kilometers of ice. But Arctic weather is nothing if not unpredictable and this particular event could just as easily fizzle as turn into an unprecedented monster.

That said, a number of concerning conditions have emerged just prior to this storm that may result in an enhanced effect on the ice. The first condition is that large sections of the Beaufort, East Siberian and Chukchi Seas are covered in thin, diffuse and mobile sea ice. These conditions are clearly visible in the surface shots provided by NASA/Lance-Modis:

In this section, as in other broad stretches of the Beaufort, the ice is reduced to a kind of slurry in which, as Neven over at the Arctic Ice Blog notes, the individual flows are completely degraded and difficult to make out. This slushy region is in direct contact with a region of mostly open water. Such areas of de-differentiated ice are likely to show greater mobility and enhanced wave action during storms, which puts them at risk of more rapid melt.

Another somewhat ominous note in advance of this storm is a rise in Arctic Ocean temperature anomalies over the past couple of days. NOAA’s surface temperature measure indicates a spreading pool of warmer than normal surface ocean conditions throughout the Arctic. In the region this storm is predicted to most greatly affect, the storm will have the potential to bring such warmer than normal surface waters into more consistent contact with the ice through the mechanical action of waves and by activating the brine channels in the ice. Further, a large pool of much warmer than normal surface water in the Chukchi Sea is likely to be driven deeper into the ice pack where it also may enhance melt.

(Image source: NOAA)

In general, there’s quite a bit of atmospheric and ocean heat energy for this storm to tap and fling about. Not only is the surface ocean warmer than 1971-2000 base temperatures, but most continental land masses surrounding the Arctic are showing highs between the mid 60s to upper 80s and lows between the 40s and upper 60s.

ECMWF model forecasts show the storm tapping some of this energy in advance of intensification, with a tongue of warm Alaskan and Canadian air being drawn into the storm at the 5,000 foot level late Monday and early Tuesday. Directly opposite, Siberia and Eastern Europe have hosted very warm air masses with daytime surface temperatures above the Arctic Circle reaching the upper 80s consistently over the past week. This warmth also encroaches just prior to storm intensification.

(Image source: ECMWF)

Added heat energy injected at the surface and at the upper levels will ensure that the vast majority of precipitation during this event emerges as rainfall.

Broader effects of this storm could be quite significant. The US Navy’s CICE models are showing a greatly enhanced ice motion throughout the duration of this storm as its counter-clockwise circulation is predicted to dramatically increase the movement of the Arctic’s remaining thick ice toward the Fram Strait. The Navy’s thickness monitor also shows a jump in ice thinning and dispersal throughout the ice pack over the duration of this event. In particular, the back end of remaining thick ice north of the Canadian Arctic Archipelago is mashed like a tube of tooth paste in the model run, pushing a broad head of ice toward the Fram. At the same time, a large section of Central ice, earlier thinned by PAC 2013, is projected to rapidly expand and further thin under the influence of this storm.

Note the rapidly expanding melt wave from the North Pole to the Laptev that appears in the final frames of the run below:

(Image source: US Navy)

So it appears we have a short duration but relatively high intensity Warm Storm event predicted to have broad-ranging effects from the Beaufort to the Central Arctic. An event that could have impacts similar to those of the Great Arctic Cyclone of 2012. Should such circumstances arise, it begs the question — is the Beaufort a region that is more likely to spawn these kinds of storms come late July through early to mid August? The region is now surrounded by increasingly warm continents. The observed weakening of the polar Jet Stream by 14% has resulted in a much greater transport of heat to the high continental boundary, as evidenced by a broad swath of heat-waves ringing the Arctic above the 60 degree North Latitude line. The increasingly thin Beaufort ice jutting out into this crescent of continental heat may well be the ignition point for major atmospheric instability, powerful storms and related heat transfer. Something to consider should these kinds of late season ice melters recur on a more frequent basis.

To this point, a new naming convention has been proposed over at the Arctic Sea Ice blog for summer storms that greatly impact the ice. Preliminary standards have been set for storms with a central pressure lower than 985 mb (at peak intensity) and a duration longer than 4 days. Suggestions for storm titles include traditional Inupiat names from this region or even the use of the names of prominent climate change deniers (My opinion is that both calling attention to major Arctic melt events and how climate change deniers have attempted to cover such events up would be an excellent use of such a convention, but I may be out-voted).

You can take part in the naming convention discussion on the Arctic Ice Blog by following this link here.

In conclusion, the potential arises for the first named Arctic Cyclone to result in dramatic melt and weakening of sea ice throughout the upcoming week. This potential heightens the risk for 2013 to be another record melt year and so we will continue monitoring the storm’s development closely for you.

2 Comments

by robertscribbler on July 22, 2013 • Permalink

Posted in Climate Change

Tagged arctic cyclone, arctic ice melt, climate change, environment, first named Arctic Cyclone, global warming, human warming, melt, record melt, science, Warm Storm, weather

Posted by robertscribbler on July 22, 2013

https://robertscribbler.wordpress.com/2013/07/22/first-named-arctic-cyclone-to-deliver-powerful-blow-to-sea-ice/

Central Arctic ‘Heat Dome’ to Replace ‘Warm Storm’ As Melt Season Shifts to New Extreme?

All the updates are in and with the major melt month of June now in the rear view mirror, it’s time take a fresh look at the volatile melt season of 2013.

In short, June melt proceeded rapidly, but not rapidly enough to break into new record territory after the slow melt month of May. Meanwhile, PAC 2013, which turned a large section of the central Arctic into a mush of broken ice faded as high pressure began to deepen and exert its own unique sets of influences over the region. As the clouds broke, air temperatures began to heat up in the Central Arctic even as anticyclonic pumping began to pull ice into the large hole formed by the storms of June. Above average temperatures ruled much of the Arctic edge as Scandinavia and North-Eastern Europe, Siberian Kamchatka, Eastern Alaska and Central Canada all showed hotter than normal conditions. The high, entrenching itself, began to pool warm air directly over the Arctic’s fractured heart…

Major Monitors Show 2013 Melted Rapidly in June through early July, But Not Rapidly Enough to Break into New Record Territory

A combination of a storm thinning the ice of the Central Arctic and hot air pulses rushing in from the ice edge resulted in a near record pace of melt for sea ice area, volume, and extent during June through early July. This furious pace of melt was fast enough to challenge previous record lows, if not to break them.

(Data Source: NSIDC, Image Source: Pogoda i Klimat)

Sea ice extent measures produced by NSIDC provide a good allegory for the overall melt trend seen in June through early July. In early to mid June, extent melt proceeded at a gradual pace at first. By late June and into early July, extent melt had drastically increased showing multiple days of 150,000 kilometer or greater loss. This extraordinarily steep pace of melt can be seen in the above graph. If such a rapid pace continues through mid July, a new record low extent level will be breached.

Currently, sea ice extent is 6th lowest on record and is only slightly above the 2007 melt line. This puts sea ice extent, according to NSIDC, about 1.4 million square kilometers below the 1979-2000 average.

To this point, it is important to consider that NSIDC has now included the extreme melt decade of 2000-2010 in its official records. So NSIDC ‘averages’ on site include these shifting goal-posts. The data set includes a declining curve and, therefore, cannot be seen entirely as ‘normal.’ Instead, it provides an anomaly base-line for a highly anomalous period and should be viewed as such. To the superficial observer, presenting the data in this fashion will somewhat serve to mask what can best be described as a sea ice death spiral. A plain example of this discrepancy is the fact that 1979 sea ice values for the same date (July 8) were about 2.1 million square kilometers higher than today. A severe decline by any measure. It is worth noting, though, that NSIDC does provide a very useful interactive tool in which all sea ice extent records are available here. (Hat-tip to Physicist-retired who provided this link in the comments section below).

(Data Source: Cryosphere Today, Image Source: Pogoda i Klimat)

Pace of sea ice area melt was also rapid during the month of June through early July with more than 4 million square kilometers lost during the five-week period. As a result, sea ice area measurements are now around 4th or 5th lowest in the record or about 1.8 million square kilometers below 1979 values. Though rapid, this melt rate still puts current measures about 800,000 square kilometers above record low totals seen for this date in 2012. So area melt will have to be steep, indeed, for new records to be reached by end of summer.

(Image Source: PIOMAS)

The critical measure of sea ice volume showed a quickening pace of decline from mid-May to mid-June. PIOMAS showed volume levels about tied with 2010 as third lowest in the measure by about June 15th. PIOMAS tends to lag a bit behind area and extent. So we don’t yet have an idea of where volume stands come early July.

That said, it is important to note that much of the region usually covered with thick ice — the Beaufort and the area north of Greenland and the CAA are substantially thinned compared to previous years. NASA’s Ice Bridge survey found this region about 8% thinner during March and April of 2013 than during the same period of 2012. Thinner ice in regions that are typically the bastion for thick ice during late summer may show much more rapid melt in July and August (especially at times when strong high pressure systems dominate the Central Arctic).

(Image provided by NSIDC as a compilation of NASA Ice Bridge Data)

Note the large region where ice thickness is 2 meters or less from the middle Canadian Archipelago and stretching on into the Beaufort. A large pulse of melt now advances from the Chukchi and along the coast of Canada and Alaska into this region. A persistent blocking pattern has also driven pulses of much warmer than normal air into this area consistently throughout June. Weather models forecast additional atmospheric warming through at least mid July. With a strong high pressure ridge now forming in the Central Arctic, this region will be one to watch for potentially rapid melt as July progresses into August.

High Pressure Forms in the Wake of PAC 2013

The dominant feature of the Central Arctic during June of 2013, a Persistent Arctic Cyclone that turned a large section of this region into an icy slurry, finally faded as of last week. The impact of this storm has now been widely accepted with NSIDC providing expert analysis on the subject:

High-resolution passive microwave concentration data from the Japan Aerospace Exploration Agency AMSR2 sensor, produced by the University of Bremen, indicate a highly unusual region of broken-up ice near the North Pole. Development of this low concentration ice may have been assisted by the cyclonic atmospheric pattern noted earlier.

…MODIS data do confirm that the ice is highly fractured with numerous small floes. Such small floes are more easily melted from the sides and the bottom by ocean waters that are exposed to the 24-hour sunlight. It remains to be seen how many of these small floes will ultimately melt completely (emphasis added).

(Image source: NSIDC)

I wrote extensively on the subject of PAC 2013 ice thinning during June. Now, NSIDC confirms a large region north of Svalbard featuring sea ice with concentrations of 50% or less that may be vulnerable to melt as July and August progress.

This condition may become particularly evident as the dipole switches from storm over the Central Arctic to clear air, warmer temperatures and higher pressure. A 1020 millibar high has already formed over the central Arctic and is expected to heighten into a 1030 millibar high by the middle of July. This thickening high will bring sunny conditions and much warmer air temperatures to the Central Arctic. It will also create an anti-cyclonic down-welling near its center. This pumping action will tend to have the effect of drawing edge ice into the hole created by PAC 2013. If the waters in the hole are substantially warmed, it is possible that enhanced melt will occur in this region even as edge ice is drawn back into the hole.

You can see some of this potential melt action predicted in the US Navy CICE model run for the 30 days from mid June through the end of next week:

(Image source: US Navy)

The effect a high like the one predicted has on sea ice is clearly demonstrated at the end of the above model run. The down-welling in the Central Arctic is seen to suck large portions of the ice in this region toward the hole formed by PAC 2013. At the edges, an upwelling action combines with counter-clockwise winds around the high to pull the ice edge inward even as the warmer upwelling waters eat away at the outliers. Note the rapid drawing in of all ice from the Beaufort, East Siberian Sea, Laptev and in a broad region north of Svalbard.

This action is the exact opposite of the effect seen during June via the impacts of PAC 2013. Then, a storm created an anomalous hole in the central sea ice even as it shoved ice toward warmer regions. Now, the rapid switch from storm conditions to strong high pressure conditions creates the potential for another unusual event: the collapse of thick ice and edge ice into the hole PAC created. Such an event would likely have an amplified effect on sea ice melt, especially in the extent measures. So we’ll will have to keep a close eye on both this building high pressure system and its interaction with the hole created by PAC 2013. Should these CICE model runs bear out, the next few weeks will be extraordinarily interesting.

It is also important to note that CICE only shows impacts through July 15th. Yet, according to ECMWF weather forecasts, a strong, 1030 millibar high is expected to last in the Central Arctic at least until July 18th.

Arctic Heat Dome Starting to Form?

To this point, it is worth noting that the weather models indicate a potential for yet another extreme Arctic weather event: the formation of an Arctic ‘heat dome.’

(Image source: ECMWF)

ECMWF forecasts show a powerful high pressure ridge developing over the Central Arctic through mid July. Associated with this high is a river of warmer air that is predicted to run directly over the North Pole. Indications are for 40 degree plus average temperatures at the 5,000 foot level by July 18th. This translates to average surface temperatures as high as the mid 50s over a broad section of the Beaufort, through the North Pole and on over to Svalbard. For the high Arctic, which averages just above freezing for this time of year, that’s a heatwave.

The establishment of this ‘dome’ high pressure system has already begun with a 1020 millibar high strengthening over the Laptev and Central Arctic. Should this ‘heat dome’ continue to strengthen and entrench as predicted, it is likely that edge melt will be greatly enhanced even as thicker ice is pulled into the melt hole created by PAC 2013 as July progresses.

The formation of such a strong high and associated warmer atmospheric temperatures during July is not conducive for ice preservation. In fact, the formation of this kind of weather system would have resulted in hastening melt even during times when the ice was thicker and more resilient. Instead, the ice suffered at the hands of a storm that, typically, would have helped preserve it. Now, the formation of a powerful high pressure system threatens a crowning blow.

So an interesting and volatile melt season continues. Anomalous storm melting of Central Basin sea ice appears to be transitioning to a powerful regime of high pressure that threatens to bring much warmer temperatures to the Central Arctic all while drawing edge ice into the deep melt hole formed by PAC 2013.

Links:

by robertscribbler on July 8, 2013 • Permalink

Posted in Climate Change

Tagged 2013 melt season, arctic melt, climate change, environment, extreme Arctic weather, extreme weather, global warming, human warming, melt, record melt, science, sea ice

Posted by robertscribbler on July 8, 2013

https://robertscribbler.wordpress.com/2013/07/08/central-arctic-heat-dome-to-replace-warm-storm-as-melt-season-shifts-to-new-extreme/

Barrow, Alaska: Near-Shore Ice Rapidly Melting, Off-Shore Ice — Gone

(Image Source: Barrow Ice Cam)

Barrow’s sea ice has borne a number of pretty severe insults over the past week. First, an Arctic heatwave sent Alaskan temperatures soaring to 98 degrees (F) in the interior, the highest temperatures ever recorded for the state. This heat pulse extended far above the Arctic Circle pushing temperatures at Barrow as high as 65 degrees (F) even as flows of warm water flooded into the Chukchi Sea from Alaska’s baked center. These high temperatures spurred an early break-up of Barrow sea ice last week. A break up that proceeded about three weeks ahead of schedule. Then, an ice-melting rain settled in, pelting the sea ice over the past three days.

Now the offshore ice is simply gone.

As you can see in the image above, huge sections of near-shore ice are melted and broken with large areas dominated by dark Arctic water. But offshore is were the greater effects have occurred. Over the past 24 hours, the off-shore ice has shrunk back and now only open ocean is visible on the horizon.

Ice break-up at Barrow occurs when off-shore ice at distances greater than 200 meters from shore begins to move. This event usually occurs on about July 8th. This year it happened on June 20th. Now, less than a week later, the ice that first broke has disappeared.

It will take a little longer for the near-shore ice to melt out. But the most important ice off Barrow — the sea ice — is now departing, retreating into a pack that is rapidly receding from the Chukchi Sea.

You can view the retreat of off-shore ice in the radar sequence below:

Note the ongoing parallel motion to shore and then the lifting away of sea ice during the last sequence.

These radar shots were taken on June 24. So final recession of sea ice occurred only four days after break-up.

Today’s radar shots from Barrow show only small chunks of sea ice remaining from a once-large pack.

(Image source: Barrow Ice Cam)

We can now say farewell to significant sea ice at Barrow, Alaska for the rest of this summer. Melt will now begin to proceed past the Chukchi Sea and into the Beaufort and East Siberian. This will likely have significant impacts once Beaufort ice begins to break as a Gyre in the center of the Sea begins to increase ice mobility and melt. Already, anchors have been weakened by both rapid melt in the Chukchi and by a large pulse of warm floodwater flowing out of Alberta via the Mackenzie Delta. This pulse of water is a direct result this week’s Canadian floods. So we’ll have to see what impact these warm flood waters have on the shore area of the Beaufort over the coming week.

Last of all, it is worth mentioning that this year’s Persistent Arctic Cyclone has tended to push more ice into the Beaufort. Over past years, the Beaufort has been much more vulnerable to melt come late July through mid-September. With early melt rapidly proceeding from the Chukchi and with areas in Canada and Alaska vulnerable to floods and heatwaves, this critical region of buffering ice will increasingly come into play as melt season progresses. The new dynamic of a PAC hollowing out the central ice as Beaufort melt and ice motion begin to crank up raise the potential for a number of volatile outcomes.

So eyes will shift to the Beaufort as these new potentials emerge.

Links:

Barrow Sea Ice Webcam

Alaskan Heatwave Sends Temperatures to 94 Degrees

2 Comments

by robertscribbler on June 25, 2013 • Permalink

Posted in Climate Change

Tagged Alaskan Heatwave, Barrow Alaska, break-up, climate change, early break up, environment, global warming, melt, science, sea ice

Posted by robertscribbler on June 25, 2013

https://robertscribbler.wordpress.com/2013/06/25/barrow-alaska-near-shore-ice-rapidly-melting-off-shore-ice-gone/

Barrow, Alaska: Heatwave Hosts Early Sea Ice Break-up

(Image source: Barrow Ice Cam)

Sea ice break-up, characterized both by melt and off-shore movement of surface ice, has now occurred off Barrow, Alaska. The event usually happens around July 8th. Since break-up was confirmed by visual yesterday, we are about three weeks early. If you want to see the video of off-shore ice breakup and movement, you can view it here.

Satellite images provided by Lance-Modis shows break-up and off shore ice motion between the days of June 19 and June 20.

(Image source: Lance-Modis)

Here’s the image of Barrow just as sea ice is starting to break up on June 19th. Barrow is located on the point of land near the lower left-hand portion of the image. Now, note how open water expands as ice shifts away in the second image below:

(Image source: Lance-Modis)

This early ice break-up off Barrow came in conjunction with a powerful Alaskan heatwave that sent temperatures in some places to the high 90s. Barrow didn’t experience the same extremes of temperature, but it did see highs in the 50s and 60s on some days. When temperatures usually hit highs around 39 degrees during this time of year, consistent highs in the mid 40s to the mid 60s is a heat-wave. And that’s what we’ve seen for more than a week now. Today’s high for Barrow is supposed to top off at around 50 degrees.

Barrow may soon see ice-free seas as a rapidly expanding melt front advances through the Chukchi and into the Beaufort Sea over the coming days. This region of melt hosts much higher than above average water temperatures that were likely fueled by the recent Alaskan heatwave which pumped air temperatures in Prince William Sound above 90 degrees. A pulse of warmer water feeding from Alaska’s estuaries and into this growing body of ice free area is likely fueling above average water temperatures.

(Image source: Lance-Modis)

Expect a large area from Barrow to Wrangle Island to be vulnerable to rapid melt as this front of warmer ocean water advances northward. The image above shows this region of open water advancing along the north coast of Alaska and into a region of the Beaufort and Chukchi Seas off shore on June 21rst.

Links:

Lance-Modis

Barrow Ice Cam

PAC 2013, The Month-Long Arctic Cyclone: Transitioning to a Warm Storm?

(Image source: DMI)

Well, it’s official. PAC 2013 has yet to give up the ghost. After transitioning to the Canadian Archipelago, it has now formed a trough composing three low pressure centers that roughly straddles Greenland, Baffin Bay, and the thickest sea ice. At this point, the storm is nearly one month old (with a formation date around May 21-26). Lowest pressures appear to be around 990 mb, but the entire region is covered in rough weather and clouds.

A look at the heat map shows the storm pulling in warmer air from the Alaskan side of the Arctic and from regions around it. This extra energy has given it enough to fuel multiple lows for an extended period. As a by-product, many regions over the Central Arctic are now above freezing. Areas near the low pressure centers still show temperatures in the range of 0 to -3 Celsius. But a broad swath of above-freezing temperatures are now under the circulation of this, rather large, storm.

(Image source: DMI)

On the map, we also notice areas of high heat concentration centered over Scandinavia, Central Siberia, Alaska, and just West of Hudson Bay. These regions of heat are both potential launching pads for more warm air invasions of the Arctic as well as feeding sources for our storm, should it continue.

And, according to forecasts, we can find that this storm isn’t done by a long-shot. ECMWF model runs show it forming troughs with numerous low pressure cells and chewing through large portions of the Arctic all the way through to July 1. Seems we were right to caution against an end to PAC 2013 in this earlier blog.

A very interesting example is the ECMWF forecast for June 27th when PAC 2013 forms a sprawling trough from the East Siberian Sea to Baffin Bay to Greenland to the Kara. It is a trough composed of not one, not two, but at least six separate low pressure cells. The forecast for tomorrow through much of the model run shows similar configurations with daisy chains of storms linked by a trough swirling along through the Arctic.

(Image source: ECMWF)

These model runs would seem to indication very stormy conditions not only for the Central Arctic, but for the periphery as well.

The ‘Warm’ Arctic Storm Begins to Emerge?

With temperatures rising to above freezing in the Central Arctic Basin and with storms projected to persist at least until July 1rst, we may receive an unwelcome glimpse of the ‘Warm’ Storm described here. Previously, I had speculated that ‘Warm’ Storm conditions would be present with moderate-to-strong cyclones persisting in the Central Arctic at a time when air temperatures ranged from 0 to 6 degrees Celsius. As we can see from the temperature map at the top of the post, we are not far off from that threshold now. And with heatwaves popping up around the Arctic there is more than enough warmth to push Central Arctic temperatures higher over the coming days and weeks.

Over at the Arctic Ice Blog (read it, join it, follow it, chat on it — you will learn boatloads), expert posters Wayne and R. Gates have noted that while clouds block direct sunlight, they can act to trap long-wave radiation. R. Gates had also linked a recent scientific study which showed that cloudy conditions from March to May enhanced rather than inhibited melt. The energy of this long-wave radiation would transfer directly to ice and ocean, so atmospheric temperatures would not be directly impacted. But more heat content in the waters and ice, overall, might be providing some of the extra kick that ECMWF appears to have missed. Another recent study by Edward Hanna found that low level clouds helped to increase the record Greenland ice sheet melt of 2012 (study here) by trapping heat near the ice. So the overall effect of clouds in cooling is less certain than one would think at first blush.

Another source of this extra heat may be via the ocean itself. As noted in previous posts, cyclonic action creates a kind of pumping force (Ekman), that can pull water up from the ocean’s depths. In the Arctic, the surface layer is cold. But underneath lies a layer of warm water fueled by the inflow from oceans surrounding the Arctic (primarily the Atlantic). As commenter Johnm33 noted, once a strong inflow of upwelling water is established, it is possible that yet more warm water is being drawn into the deep Arctic Ocean from the Atlantic. If this warmer inflow was pumped to the surface, it would add to atmospheric heat beneath the storm.

Lastly, the atmosphere, via high amplitude waves in the Jet Stream is now also providing its own source of heat by dredging deep into the lower latitudes and pulling warmer air up into the Arctic. So far this summer, we have seen record heat waves in both Scandinavia and Alaska. These heat waves were caused by persistent blocking patterns that injected heat into these Arctic locations. Scandinavia saw temperatures in the 80s, Alaska saw temperatures rocketing into the upper 90s. The Jet Stream configuration allowing for these hot air injections at these locations still persists and are plainly visible on the current Jet Stream map:

(Image source: California Regional Weather Service)

Note the large wave in the Jet Stream (and associated warmer air) now riding up over Alaska and deep into the Beaufort, Chukchi, and East Siberian Seas. Another pulse is visible lunging up through Scandinavia. A third, though less southwardly linked, pulse is also now rising over Eastern Siberia. These extraordinarily high amplitude waves all cross far beyond the Arctic Circle. An atmospheric condition that is anything but normal and one that is also continuing to supply warmer air to the Arctic environment, even one covered by a storm that would normally substantially cool the atmosphere there (for more information on how snow and ice melt in the Arctic is enabling these high amplitude Jet Stream waves, take a look at some of the work of Dr Jennifer Francis). Instead, as the discrepancy with ECMWF predictions and surface observations shows, we have temperatures that are only .5 to 1 degree C cooler than average under the storm (they should be about 3-7 C cooler) and much, much warmer conditions surrounding it.

A Warm Storm persisting in the Central Arctic for long periods is a potential nightmare scenario for sea ice melt. Currently, we have warming conditions in the Central Arctic, a spate of record heat-waves at the periphery in places like Alaska and Scandinavia, a mangled Jet Stream that keeps pumping warmer air into the Arctic, and a storm that is now projected to persist until at least July 1rst. So we now have to consider at least the temporary emergence of the Warm Storm to be a possibility going forward.

Impacts to Sea Ice Still Ongoing, Likely to Ramp Up

A substantial thinning and chopping up of the sea ice is now apparent in all visible (when you can see through the clouds), concentration, and thickness monitors. Now, a wasteland of thinned, shattered and broken ice is visible in a swath from Svalbard all the way to Wrangle Island near the Bering Strait. A comprehensive graphic summary of these impacts is provided below:

(Image source: US Navy)

The current image, provided by the US Navy is a stark contrast to conditions seen at the end of May. This thickness measure shows a long ‘claw’ of much thinner ice reaching all the way in to the Central Arctic and encompassing the North Pole. This graphic reveals very poor Central Ice thickness conditions for mid-to-late June.

(Image source: US Navy)

The US Navy surface concentration graphic also reveals very broken conditions for the Central Arctic in mid-to-late June.

(Image source: Uni Bremen)

Uni-Bremen has been providing consistent confirmation of ice damage and fragmentation due to the Ongoing Arctic Storm for nearly two weeks now. Here’s the most recent concentration monitor showing the broad swath of broken ice.

(Image source: Cryosphere Today)

And Cryosphere Today, which is less sensitive than the other monitors shows low ice concentrations stretching from Svalbard to Wrangle Island.

Overall, should PAC 2013 continue to warm even as it persists, it should have ever-greater deleterious effects on the Central Arctic sea ice as mid-to-late June transitions into July. The US Navy thickness forecast shows ongoing thinning and fracturing in this region all the way through June 28th. One interesting feature of note in this forecast is that it appears a substantial section of ice will be separated from the main pack and stranded in the Kara Sea if current trends continue through early July.

(Image source: US Navy)

The Storm That Just Won’t Quit

So, apparently against all odds, PAC 2013 continues and, even worse, shows risk of beginning a transition to a ‘Warm’ Storm in the Central Arctic. Should this trend remain in effect, increasingly visible damage to the central ice is likely to become ever more apparent as June turns to July.

Links:

Neven’s Arctic Ice Blog

California Regional Weather Service

Jennifer Francis Explains How Sea Ice and Snow Melt impact the Jet Stream

The Warm Arctic Storm

11 Comments

by robertscribbler on June 21, 2013 • Permalink

Posted in Climate Change

Tagged 2013 melt season, Arctic heatwave, environment, global warming, Heatwave, melt, PAC 2013, Persistent Arctic Cyclone, record melt, science, sea ice, Warm Storm, warming, weather

Posted by robertscribbler on June 21, 2013

https://robertscribbler.wordpress.com/2013/06/21/pac-2013-the-month-long-arctic-cyclone-transitioning-to-a-warm-storm/

The Arctic Heatwave: Greenland, Alaska, Scandinavia, Heat Domes and a Mangled Jet Stream

Over the past year, we’ve now experienced three major heatwaves north of the Arctic Circle. Greenland melted under a freakish blanket of heat-trapping clouds, Scandinavia saw an early June heatwave that sent temperatures into the 80s, 30 to 40 degrees hotter than normal, and just this week Alaska experienced record heat that sent temperatures there into the upper 90s, probably the hottest temperatures ever recorded there.

Now, a combination of new research reveals changes to the Jet Stream that enable warm air to enter the Arctic even as a thickening atmosphere sets in place conditions where powerful ‘heat domes’ are more likely to form.

Unprecedented Heat, Melt In Greenland

Our story begins in Greenland during July of 2012. At that time, a powerful blocking pattern enabled a strong high pressure system to form over that frozen land. An upward swing in the jet stream pumped ever-warmer air over its vast ice sheets. Finally, record temperatures were reached both along the coast-line and even at the center of its three kilometer high glaciers. Temperatures in the Greenland interior rocketed to 60 degrees.

(Image source: Nicolo E. DiGirolamo, SSAI/NASA GSFC, and Jesse Allen, NASA Earth Observatory)

Within only a few days, almost the entire ice sheet was experiencing some kind of melt. A record 90% of the ice sheet succumbed, far out-pacing the previous record of 52 percent set just two years before in 2010.

Draped over top of this melt was a freakish layer of low clouds. Clouds are, generally, thought to block heat from the sun. But, in this case, it appeared the clouds had locked heat in, recirculating it and keeping it close to the ice, forming a heat-trapping blanket over Greenland.

Far above this low cloud layer, the atmosphere was growing ever thicker. A towering high pressure system known as a heat dome was sucking in the warmer air from around and beneath it, trapping it in a denser and denser layer. From the south, a long-period, very persistent blocking pattern fed warmer, moister air into this heat dome. Meanwhile, the sea ice, which had tended to insulate Greenland from direct assaults of heat in the past, had retreated far behind its usual summer lines of defense.

As a result, Greenland baked.

In the media, contrarians did their best to down-play what was clearly a catastrophic event. They retreated to their usual ‘natural variability’ claims. But the closest event bearing any similarity to the 2012 event happened in the 19th Century and it didn’t occur at the end of a long string of worsening melt. Context formed a mire which contrarians were having ever-greater difficulties extracting themselves from.

The Scandinavian Heat Wave

But context was coming back to haunt us yet again as June 2013 rolled around. This time, another blocking pattern had emerged — creating a strange whirl in the Jet Stream. The path of atmospheric current followed a course much like a river bends through a marsh. It coiled, snake-like, bending back on itself, forming cut off circles.

This punch of colder air extended from Greenland all the way into central Europe. This extrusion of Arctic atmosphere resulted in one of the most extreme winter/spring periods Europe has ever experienced. Record snows were followed by record floods. By June, some water gauges on Europe’s largest rivers recorded the highest levels since the 1500s. It was the third 1,000 year flood to occur within the last 13 years.

But the colder, stormier air didn’t penetrate any deeper than Eastern Europe. There, it doubled back on itself, heading up and back into the North Atlantic. In front of this coil of air, this blocking pattern that had persisted over Europe since winter, rose a burst of heat. This pulse flowed into Scandinavia where it stagnated. Heat pooled in this region and, in a few days, records were being shattered across such improbable Arctic regions as Finland. 80 degree temperatures reigned in a region that usually experienced 40 degree weather this time of year.

In about a week, the Scandinavian Heat Wave had backed off, but temperatures remained well above average into mid-June.

The Alaskan Heat Wave

But heat was, again, about to re-emerge just two weeks later in another improbable region of the Arctic.

This time, a blocking high pressure system that had created a high amplitude wave in the Jet Stream over the Pacific Ocean just south of Alaska and west of British Columbia was about to preform an exotic trick. Alaska, resting just north of this blocking ridge had lain beneath a front of cold air for much of May. So while areas of California, Nevada, Arizona, Washington, Oregon, and British Columbia were experiencing abnormally warm conditions, Alaska experienced temperatures that had plunged into record low territory for many cities.

Contrarians proclaimed the end of global warming for Alaska. But the heat was coming and they only had to wait one month. By June, the blocking pattern which had kept cold air to the north and warmer air to the south began to edge into Alaska. Temperatures flipped from the 20s to the 70s for many regions. Barrow, which had experienced a warmer than average winter and spring, saw temperatures rise into what, for it, was the balmy 40s.

But this pulse of warmer than average air wasn’t finished. The current of Jet Stream cut off, giving this warm high pressure system an encapsulating band of winds. Conditions were now right for the formation of another heat dome. And form it did. By Monday of this week, temperatures had rocketed to 98 degrees in some places of the Alaska interior, possibly breaking the all-time record high for the hottest temperature ever recorded, at any time, in Alaska.

Today, temperatures for Barrow, one of the coldest cities on Earth, are projected to hit 70 degrees, about 31 degrees above the average high for this time of year.

Greenland, Scandinavia, Alaska, three record heat waves above the Arctic Circle all in the last year. What in the world had happened to the weather?

Enter the Experts…

A number of climate scientists and meteorologists have begun to grapple with the new, unstable regime of weather gripping the Arctic. These include Dr. Jennifer Francis of Rutgers University, Stu Ostro of The Weather Channel, and Dr. Edward Hanna of the University of Sheffield.

Dr. Francis, last year, provided compelling scientific evidence that the erosion of Arctic sea ice and the rapid melt of Northern Hemisphere snow cover during the summer time resulted in changes to the Jet Stream. This erosion of sea ice and land snow resulted in less of the Arctic’s cold air being trapped within the Arctic. It also resulted in more floods of warmer air coming up from the south. This north-south motion of air masses had the net effect of reducing the temperature difference between the Arctic and the mid-lattitudes. As a result, the river of air surrounding the pole known as the Jet Stream began to slow down, forming large dips and bulges.

As these dips formed and the air slowed, the Jet Stream had more of a tendency to become stuck. This sticking in place created ‘blocking patterns’ in which a given set of weather was more likely to persist over long periods of time. Recent examples of these blocking patterns and their related weather include Europe’s extreme winter and spring of 2012-2013 and the 2012 US Heatwave and related 2012-2013 drought. Further, without the collision of Arctic and Tropical air masses enabled by a massive dip and up-swing in the polar Jet Stream near the US East Coast, it is doubtful that the Hybrid Superstom Sandy would have ever formed.

Dr. Francis notes an increased frequency of such extreme, blocking pattern spawned, events and the picture she paints provides us with a much better understanding of how climate change is impacting our weather.

Recently, Dr. Francis spoke on the subject of climate change in an event entitled “The Alarming Science Behind Climate Change’s Increasingly Wild Weather” with the weather Channel’s Stu Ostro. Stu brings a different yet complimentary set of knowledge to the new observations presented by Dr. Francis. Over the past couple of decades, Stu has noted what appears to be a ‘thickening’ of the atmosphere. He equates it to a cake batter which, when heated, tends to rise. This rising atmosphere, according to Stu, has led to the formation of powerful, persistent high pressure systems. As Stu noted in a recent article in Mother Jones:

“The frequency of these really strong ridges of high pressure aloft, these anomalous high pressures aloft are increasing.”

And the result is some rather alarming consequences.

A recent paper headed by Dr. Edward Hanna at the University of Sheffield implicates both the mangled Jet Stream and a powerfully thickened high pressure system in the record 2012 melt in Greenland. According to the paper:

Our analysis allows us to assess the relative contributions of these two key influences to both the extreme melt event and ongoing climate change. In 2012, as in recent warm summers since 2007, a blocking high pressure feature, associated with negative NAO conditions, was present in the mid-troposphere over Greenland for much of the summer. This circulation pattern advected relatively warm southerly winds over the western flank of the ice sheet, forming a ‘heat dome’ over Greenland that led to the widespread surface melting.

Dr. Hanna’s paper pointed out the movement of warmer air over Greenland via a strong blocking pattern in the Jet Stream and the building up of a powerful ‘heat dome’ and blocking high pressure system over the ice sheets. Hanna also added the contribution that lower level clouds enhanced, rather than inhibited, melt.

Together, this research points toward how receding sea ice and a warming climate are setting in place conditions that are causing these Arctic heat waves. And the recent heatwaves in Greenland, Scandinavia, and Alaska provide excellent illustrations of the kind of events we can expect with greater frequency in the future.

Links:

Nicolo E. DiGirolamo, SSAI/NASA GSFC, and Jesse Allen, NASA Earth Observatory

Dr. Jennifer Francis: Understanding the Jet Stream

One Meteorologist’s Come to Jesus Moment on Climate Change

‘Heat Dome’ Melted Ice Sheet in 2012

Atmospheric and Oceanic Climate Forcing of the Exceptional Greenland Ice Sheet Surface Melt in Summer 2012

Heatwave Sends Temperatures in Alaska to 94 Degrees

Human Climate Change is Wrecking the Jet Stream: UK Met Office Calls Emergency Meeting

Arctic Sea Ice Melt, Methane Release Shows Amplifying Feedbacks From Human-Caused Climate Change

2 Comments

by robertscribbler on June 20, 2013 • Permalink

Posted in Climate Change

Tagged Alaskan Heatwave, Arctic heatwave, climate change, environment, glacial melt, global warming, Greenland Heatwave, Greenland record melt, Heatwave, human warming, melt, Scandinavian Heatwave, science, sea ice melt, weather

Posted by robertscribbler on June 20, 2013

https://robertscribbler.wordpress.com/2013/06/20/the-arctic-heatwave-greenland-alaska-scandinavia-heat-domes-and-a-mangled-jet-stream/

Heatwave Sends Temperatures in Alaska to 94 Degrees. Large Pulse of Warmth Envelopes Beaufort, Chukchi, and East Siberian Seas.

Yesterday, temperatures in Prince William Sound hit upwards of 93 degrees. Communities there, including Valdez and Cordova, both set new record highs. Talkeetna hit 94 degrees, also an all-time record high for the date. Meanwhile, Seward hit a new record of 88 degrees Fahrenheit. Temperatures in the interior rose to between the mid 80s and lower 90s.

This pulse of heat was driven by a persistent bulge in the Jet Stream over the Pacific Ocean, the Western United States, and the Pacific Northwest that has been present since mid winter. The bulge has resulted in warmer than normal temperatures and drier conditions for much of the Western US while keeping temperatures warm for western Canada and Alaska. It is a blocking pattern implicated in the ongoing drought conditions in places from Colorado to Nevada and California. A pattern which sees 44% of the US still locked in drought.

Sunday and Monday, this blocking pattern enabled warm air to flood north into Alaska, setting off a record heatwave there. You may not think of 50 and 60 degree temperatures in Barrow, Alaska as a heatwave. But when average highs for June there are about 38 degrees, 50 and 60 degree weather is quite hot for this time of year.

Last Thursday saw temperatures in Barrow above 60 degrees. Today, so far, temperatures have risen to 52 degrees, though the high will probably not be reached for a few hours yet.

All this warmth is doing a number on sea ice in the region. As I posted yesterday, large, dark melt ponds and holes in the ice are now visible off Barrow. You can see them in the most recent Barrow Ice Cam shot below:

(Image source: Barrow Ice Cam)

Note the near-shore melt as well as the large, dark holes forming and widening off-shore.

The pulse of warm air riding up into Alaska is common to a warmer air mass now pervading much of this region of the Arctic. As a result, above freezing temperatures have now invaded large sections of the Beaufort, Chukchi, and East Siberian Seas. This warmer air is causing melt ponds to form over the region leaving their tell-tale bluish tint in the satellite pictures.

(Image source: Lance-Modis)

In the above image you can see this bluish tint covering about half of the Arctic Ocean area represented in the picture. Also note the large and rapidly expanding area of open water north of the Bering Strait and the large and expanding cracks over the East Siberian Arctic Shelf.

Ice of this color indicates a speckling of melt ponds and hints at the ongoing impacts of solar insolation on the sea ice. Warm conditions in this region have favored insolation for at least the past week. And persistent warmer, clearer weather is beginning to enable the sun to do some serious work on the sea ice.

Warmth is expected to continue for this area until at least next week. The latest long-range forecast from ECMWF shows above-freezing and even 50 degree temperatures plunging deep into this region of the Arctic all the way through late June.

(Image source: ECMWF)

By June 28th we have 40 degree average temperatures extending far off-shore with above freezing temperatures covering much of this section of the Arctic. Melt in this region, therefore, is likely to be greatly enhanced as the sun is provided with an extended period during which to do its work.

Links:

Heatwave Sets Records Across Alaska

by robertscribbler on June 18, 2013 • Permalink

Posted in Climate Change

Tagged 90s Alaska, Alaska heatwave, Arctic, Blocking Pattern, environment, extreme melt, extreme weather, global warming, human caused climate change, jet stream, mangled jet stream, melt, record melt, science, sea ice, weather

Posted by robertscribbler on June 18, 2013

https://robertscribbler.wordpress.com/2013/06/18/heatwaves-sends-temperatures-in-alaska-to-93-degrees-large-pulse-of-warmth-envelopes-beaufort-chucki-and-east-siberian-seas/

Large Melt Ponds Forming at Barrow, Alaska

(Image source: Barrow Ice Cam)

Over the past week, large melt ponds emerged off the coast of Barrow Alaska. These ponds formed after successive days of ‘warm’ weather with highs ranging between 40 and 65 degrees Fahrenheit. Constant sunlight and above-freezing temperatures in this region have also contributed to the formation of numerous smaller melt ponds and large holes in the sea ice.

Break-up of sea ice off Barrow usually occurs in early to mid July and is characterized by off-shore ice moving parallel to the coast. On the films provided by the Barrow Ice Cam site, sporadic ice motion was visible during a number of days over the past week. So it appears that ice break-up is currently ongoing, if not quite complete. If confirmed, the break-up at Barrow for this year will be a few weeks ahead of schedule.

Between February and March of this winter, powerful off-shore winds drove ice away from the coast even as it created an upwelling of warm water currents from beneath. The result was a rare appearance of open water during winter. But freezing temperatures and an abating of the winds caused the sea ice to rapidly return and re-freeze.

The current melt is well under-way and will be far more permanent than the brief opening of water that appeared in March. The ice near Barrow has suffered a long pummeling from sunlight and above-freezing temperatures. Now it appears ready to relinquish its grip on this frozen city, if only for a brief time.

Links:

Barrow Sea Ice Cam

Open Water Visible at North Pole Camera 1, Cracks Visible at Camera 2

(Image source: APL)

Last week, North Pole Camera 1 began to record visual images of cracks on the surface of sea ice. Now, just one week later, open water is visible in the same location. Meanwhile, cracks are beginning to show up in the vicinity of North Pole Camera 2.

On the ice near these cameras, our Persistent Arctic Cyclone, which has continued to thin the Arctic’s Central ice since late May, is beginning to have a very visible effect. Though the storm center has moved away, leaving these areas mostly sunny, the agitated ocean beneath the ice is making its presence known through cracks and open stretches of water near both of these cameras.

At North Pole Camera 1, to the right hand side of the most recent shot, open water is visible. The best way to see it is to look straight ahead at the anemometer, whose top establishes the horizon. Then, look to the right. There a growing wedge of blue-grey, indicating open water, appears. If you look closely at this section of the image, not only can you see open ocean, but breaking waves are also visible at the ice edge. (It works very well if you have a touch screen you can use to zoom in on this section of image).

Once you locate the ice edge, follow it with your eyes. At this point, we can notice breaking waves from horizon to horizon within the frame of the picture. These features, though subtle, are plainly present.

Given this opening of water near Camera 1, one wonders how much longer this camera will keep sending pictures to us.

At North Pole Camera 2, a crack in the ice has now also developed.

You can see this crack in the image below:

(Image source: APL)

If you look to the left-hand side of this image, you can see a thin, black crack appearing in the distance.

APL has managed cameras near the north pole for years. This is the first time we’ve been able to see cracks and sections of open water from cameras located so close the central sea ice. These images are being taken in early June. A clear sign that the central ice is far more fragile than usual for this time of year, much less any time during summer whatsoever.

2 Comments

by robertscribbler on June 14, 2013 • Permalink

Posted in Climate Change

Tagged Climate, cracks, global warming, melt, north pole, science, sea ice

Posted by robertscribbler on June 14, 2013

https://robertscribbler.wordpress.com/2013/06/14/open-water-visible-at-north-pole-camera-1-cracks-visible-at-camera-2/

NASA/UC Study: Warming Ocean Shown to Melt Ice Sheets From Below

(Image source: NASA)

A new study produced in Science shows that a warming ocean is causing at least 55% of the ice melt seen in Antarctica.

The study, run by NASA and Eric Rignot at the University of California, Irvine, shows that basal melting, or melting from below, was responsible for a majority of Antarctic melt. Contact with warm ocean currents was found to erode the ice in a way that was previously undetected. Warming waters, driven by wind and currents, swept against the ice at numerous locations on the ice shelves’ underbellies, carrying away larger and larger volumes of glacial melt.

Until recently, this process was invisible and, therefore, not included in the science of ice sheet dynamics.

The ice shelves, which act as stoppers keeping interior glaciers from sliding into the ocean, are critical to keeping the Antarctic ice sheet healthy. So discoveries of how ice sheets melt are of key importance to both glacial and climate science. And the fact that warming oceans are eroding the ice from underneath is some cause for concern. From NASA:

Antarctica holds about 60 percent of the planet’s fresh water locked into its massive ice sheet. Ice shelves buttress the glaciers behind them, modulating the speed at which these rivers of ice flow into the ocean. Determining how ice shelves melt will help scientists improve projections of how the Antarctic ice sheet will respond to a warming ocean and contribute to sea level rise. It also will improve global models of ocean circulation by providing a better estimate of the amount of fresh water ice shelf melting adds to Antarctic coastal waters.

The image below, compiled by NASA and based on the study’s findings shows how ocean-driven melt rates compare to glacial calving. Overall melt rates are indicated by the red-to-blue color shift and related scale in the upper left corner of the image.

(Image source: NASA)

The study built on previous findings in Nature showing that wind-driven ocean currents played a major role in ice sheet melt. Together, these results are challenging previous understandings of ice sheet melt. Past analysis of ice sheet health had assumed that most ice losses occurred during glacial calving events. What Rignot and Pritchard (author of the Nature study) found was that ocean-glacier interaction was a more important factor in overall ice melt.

“This was quite a big gap in our understanding of how the ice sheets interact with their surroundings, and what it shows is that the oceans play a bigger role than we’d previously thought,” said Pritchard about the new study’s results in a Scientific American interview.

Melt From Below

That a warming ocean is a powerful driver of ice melt makes sense. Water contains more heat energy than air and so a given volume of water at a given temperature would have more potential to melt ice than the same volume of atmosphere. Pritchard and Rignot’s findings have major implications for modeling ice sheet melt and could help improve global models. They may also lead the way to a better understanding of ice melt in general.

Sea ice model melt forecasts have also suffered due to a lack of understanding of how the ocean interacts with floating ice. This missing data has led the models to vastly under-estimate sea ice melt in the Arctic. It has also resulted in a general failure in the understanding of how storms affect sea ice floating on the surface of a warming ocean. Scientists and forecasters also often down-play or ignore the impact warm water upwelling, churning or ice sheet contact with warming water currents can have on overall melt rates.

The Pritchard and NASA/Rignot studies of basal melt in Antarctica may, therefore, have broader implications for understanding ice melt around the globe. Most large continental glaciers have contact with the ocean and the sea ice floats on the ocean surface. A dynamic interaction between the ice and ocean is, therefore, ongoing. So improvements to understandings of this interaction are likely to better resolve our forecasts for future melt.

Links:

Oceans Melt Antarctica’s Ice From Below

Antarctic Ice Sheet Loss Driven by Basal Melting of Ice Shelves

Ice Shelf Melting Around Antarctica

Warm Ocean Causing Most Antarctic Ice Shelf Mass Loss