(Image Source: CICE)
A moderate-strength cyclone that emerged about six days ago and is expected to last at least until Monday is slowly chewing away a large area of Arctic sea ice near the North Pole. Cyclonic action generated by the storm is now resulting in an unprecedented thinning of central Arctic sea ice. It is important to note that should this ice thinning continue, it could have major impacts on end summer sea ice this year.
The low that is causing the trouble moved out of the region of the Beaufort Sea, skirted East Siberia and had transitioned into the central Arctic Ocean by about May 24th. Since then, it has persisted, remaining nearly stationary with a slow drift back toward the Beaufort. Forecast maps show the low remaining in this region until at least Monday before it weakens and moves toward the Mackenzie Delta. Strangely, long-rage forecasts show it re-strengthening even as it returns to the central Arctic.
(Image source: DMI)
Minimum central pressure continues to hover around 990 millibars. This moderate strength compares to the much stronger Great Arctic Cyclone of 2012 which bottomed out around 960 millibars. However, the storm is quite strong for this time of year, when Arctic cyclones tend to be rare and weak, containing enough energy to generate winds that erode sea ice.
This erosion takes place via a pumping process by which the ice is pushed against the ocean surface by the cyclonic wind field. This motion, in turn, stirs up the underlying waters creating a warm, upwelling current. Since the forces occur over broad regions, powerful surface forces allow the upwelling to dredge deep, causing mixing between surface and lower layers. Tendrils and micro-currents of warmer water thus rise to contact the ice. This action can melt the sea ice from below, breaking it into smaller chunks, opening polynas, and riddling the ice with leads. If the storm grows strong enough, large wave action can devour whole sections of ice. But, in this case, the storm does not appear to be powerful enough to generate this kind of wave action.
Since 2012, we have already seen two major upwelling events. One, already mentioned, was the Great Arctic Cyclone of 2012. The second, involved strong off-shore winds during February and March which pushed ice away from shore and, in the region of Barrow Alaska, resulted in near-shore upwelling that temporarily melted ice even as it was pushed out to sea. The combined result was open water during winter.
We can see the storm’s current and projected impacts on the CICE model run posted at the top. CICE is projecting the development of a large area of thin and fractured ice near the North Pole in the storm’s wake even as a region of thick ice north of the Canadian Arctic Archipelago erodes. These projections show average thickness in a wide region falling from about two meters to less than one meter.
That’s very thin ice for North Pole regional waters.
Already, some impacts from the storm are visible in Lance-Modis shots of the region.
(Image source: Lance-Modis)
In the above shot, we can see the center of our moderate-strength cyclone near the middle-left portion of the image. To the right of the storm center, we can see down through the clouds to areas where the ice has fractured, revealing the dark blue waters beneath. Below the storm center and near the lower left-hand corner of the image is the North Pole. So what we are seeing is a broad area of leads and fractured ice with gaps measuring up to about 5 km wide within 200 miles of the North Pole. This kind of development is not at all usual for late May, much less late August.
CICE model runs show ice in this region continuing to thin, fracture and weaken as the storm passes.
As the storm moves away, it is expected to pull warm air in behind it, which could further weaken the ice. ECMWF weather forecasts show this warm air influx occurring by about June 4:
(Image source: ECMWF)
In the above image, we see 5 degree C temperatures plunging directly into the heart of the Arctic. A powerful late spring event should it emerge.
In the past, storms of this kind have had very little impact on sea ice. However, this year the ice is very thin and spread out. Most ice in the Arctic is showing a thickness of two meters or less. Records of past melt seasons show that two meter or thinner ice is unlikely to survive the melt season.
Furthermore, packs of much warmer air are drawn closer to the Arctic center by a wavy pattern in the jet stream. The result is that large north-south swoops draw warmer air up from the south even as they push Arctic air into more southerly regions. Europe, in particular, suffered due to this mangling of the jet stream. Ironically, a growing body of scientific evidence shows that these very changes in the jet stream are a result of loss of sea ice. So it appears that loss of sea ice is resulting in a snow-balling of forces that contribute to its ultimate demise.
The ultimate result is an Arctic-wide ice thinning impacting even the most central and protected areas. Even in this region of the central Arctic, where ice is usually much thicker, large regions of 2 meter or thinner ice dominate. You have to venture closer to Greenland and the Canadian Arctic Archipelago to find areas of ice thicker than 2 meters. However, as the recent evacuation of a Russian Arctic Expedition in that region shows, even the thickest ice is far more fragile than before.
The result of all this thin and broken ice is that it is much more vulnerable to surface conditions. A storm moving over thin and broken ice is much more likely to churn it up, breaking it and mixing it with the warmer waters underneath. Last year, we saw this process in action during the powerful Great Arctic Cyclone which emerged in August, churning up a large area of the Beaufort Sea, then drawing warm air in behind it, resulting in major sea ice losses.
At times when ice was thicker, moderate or powerful storms would not pose a threat for enhanced melt. But since 1979, the Arctic has suffered an 80% loss of sea ice volume.
This year, sea ice volume is currently at record low levels. Yet the ice pack is very spread out, boasting an area near 2002 values. This combination of wide coverage and low volume leaves the ice very, very thin and fragile. So now, even moderate cyclones like the one hovering near the North Pole can chew away at the ice.
If the CICE projections bear out, we’ll see the central ice pack greatly weakened in the wake of this storm just as solar radiance and warm air build into mid-June. At this point, such injuries to the ice make it more likely that rapid and catastrophic decline in coverage will begin to dramatically ramp up over the next few weeks.
As Neven over at the Arctic Ice Blog notes:
I feel the Arctic sea ice pack could soon go POP under the right conditions.
Let’s see:
- Thin, spread-out ice pack.
- Persistent storm chewing away the central ice.
- Large cracks and areas of open water riddling most of the ice pack.
- Large polynas forming behind the ice edge.
- Upwelling events eroding the bottom ice.
- Loss of Arctic expeditions in the region of the ‘thickest’ ice.
- June heat and constant, direct sunlight approaches.
Looks to me like a lot of the ‘right’ conditions are present.
In short, don’t let the high extent and area numbers fool you. The thin, spread out state of the ice leaves it more vulnerable, not less so. The sea ice is weaker and less resilient than it ever was. Only a cold summer and conditions favorable for ice retention are likely to prevent a record melt in either area, volume or extent. On the other hand, very bad conditions could result in near-total melt (under 1 million square kilometers end season area).
UPDATE:
Long-range weather models show the cyclone sweeping down toward the Mackenzie Delta, drifting back toward the Canadian Arctic Archipelago and finally returning to the Central Arctic by mid-June. Such a prolonged storm event would likely have a continuous weakening affect on the ice. Lower temperatures in the storm’s region would be more than countered by active wave energy and tapping of warmer, deeper waters which will have a tendency to erode the ice from beneath. Furthermore, warmer air is shown to follow in the wake of this storm, which may enhance melt through regions of already weakened ice.
In any case, this is a situation that bears close watching. A month-long, or more, storm harrying the Arctic could have quite an impact.
ECMWF weather model forecast for June 9th:
(Image source: ECMWF)
Links:
robertscribbler 
T.O.O.
/ May 31, 2013Excellent synopsis and quite a contrast in both tone and content to the science-free Steve Goddard / Real Science site.
This is actually very depressing — what will be the effects on the climate from an Arctic that has 10% or less of its ice compared to just a few decades earlier?
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robertscribbler
/ May 31, 2013Goddard tries to cover up what science reveals. It’s a losing proposition in the end. But, hey, if he can help prevent action on climate change, then how much further into that bad future do we end up?
As for what happens without summer sea ice?
1. More heat absorbed by summer oceans means global warming and climate change speed up. Greenland melt increases, and northern hemisphere weather is a mess.
2. The jet stream first slows down (happening now), then reorients to Greenland and speeds up. This results in very, very bad storms (according to models).
3. Greenland ice melt increases pushing sea level rise higher and dumping lots of cold water into the Atlantic. Europe’s weather becomes really nasty due to shifting climes and possible diversion of the Gulf Stream.
4. Once Greenland melt really gets going, Hansen warns of ‘continent sized frontal systems that pack the punch of hurricanes’ in “The Storms of My Grandchildren.” At current pace, these could emerge by 2040-2060. Such storms make Sandy look like a walk in the park.
5. A warmer Arctic means amplifying feedbacks to human caused warming — tundra methane release, increased heat absorption by the Arctic Ocean, methane hydrate release in certain areas. Together, these can add 2-4 degrees to human warming long-term.
6. Growing seasons become a mess due to alterations in weather patterns.
These are just a few of the short and long-term impacts of loss of sea ice. They won’t happen all at once, but they are likely to slowly ramp up.
It is depressing. In my view that’s why we need to do as much work to prevent as much damage as possible.
I guess it’s easier to believe Steve’s comfortable non-science?
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Sourabh
/ May 31, 2013Hi Robert,
Excellent analysis of arctic weather and sea ice conditions. I have been following your blog for past five-six weeks. Though depressing, I hope arctic melts faster and sooner, so that we can start having real conversation. For past few days, arctic ice extent increased slightly, that depressed me because Goddard already started “recovery” campaign on his website.
Unless we have more hurricanes like Sandy, the deniers won’t let everyone else do anything. So, its better to have a climate catastrophe sooner rather than later.
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robertscribbler
/ May 31, 2013Have to agree that a little pain now would be better than a lot of pain later. That said, Goddard would have to see volume increase by a factor of 5 at end summer to be able to rationally speak about recovery. He’s niddling around about sea ice extent and area, and cherry picking the days when it’s close to ‘normal.’ He’s about as far outside reality as one can be on a subject. Say, for example, you bought stock and it had gone down 55%. If, for one day, the stock was only down 30%, you couldn’t really call that a recovery, especially if, by next year, the stock was down by 60%. That’s the logic Goddard is using and he’ll be picking cherries all the way to zero sea ice.
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