Friday, 11 March 2016

Another polar melt record in February

Northern Polar Melt Re-Asserts With A Vengeance — Arctic Sea Ice Volume Closed on New Record Lows During February

10 March, 2016

Arctic sea ice volume hit near new record lows during February. That’s kinda a big deal. What it means is that whatever sea ice resiliency was recovered during 2013 and 2014 are now mostly gone. That record all-time lows for sea ice set in September of 2012 are likely to see a serious new challenge during 2016 and 2017.
A flood of severe Arctic heat — flowing up through the Barents and Greenland seas in the East and over Alaska and the Bering Sea in the West — has been hammering the Arctic Sea Ice all Winter long. During February of 2016, new record lows in sea ice extent and area were breached. Meanwhile, sea ice volume — as measured by PIOMAS — also greatly declined to hover just above previous record lows for this time of year set in 2011.
PIOMAS Daily Volume
(Arctic sea ice volume, as measured by the Polar Science Center, plunged back to near record low territory during February. Many consider sea ice volume to be the key measure determining sea ice health. So these new drops in the volume measure are a bit spine-tingling. Image source: Wipneus.)

Looking at the above graph, provided by Wipneus, and based on model and observation data collected by the Polar Science Center, it appears that for some days during February, volume measurements even briefly descended into record low territory. As of early March, volume totals were in the range of just above 20,000 cubic kilometers — beating out 2012 as second lowest volume on measure and hovering just above 2011.

Winter Warming Grand Final

Over the past ten days, abnormal warmth in the Arctic has faded somewhat. The lower Latitudes have heated up with the onset of spring and this has tended to strengthen the circumpolar winds. Perhaps the last bit of seasonal change that can have this effect given the alterations to atmospheric circulation produced by a human-forced warming of the globe and a particular high concentration of this added heat centering on the Arctic.
Ironically, the time-frame of late February to mid-March is when the higher Latitudes in the Northern Hemisphere tend to experience their coldest temperatures. During 2016, we did see some of this atmospheric effect take hold. As a result, temperatures in the High Arctic above the 80 degree North Latitude line have fallen from record warm readings in late February to far above average warm temperatures over recent days.

Temperature above 80 north
(Ever since Early January, Arctic temperatures have been in near record or record warm ranges. This consistent heat has resulted in the warmest Winter temperatures ever experienced for the region above the 80 North Latitude Line. Image source: CIRES/NOAA.)

Today, another very strong pulse of warmth is building up through the region of the Barents and Greenland seas. This heat pulse representing yet another warm wind event for 2016. Another very strong south to north atmospheric draw flooding in front of yet another chain of strong low pressure systems in the North Atlantic. A flow of heat drawn up from the tropics and delivered to the Arctic that will briefly drive regions near the North Pole above the -2 C melting point of sea ice even as a wide wedge of 20 degree Celsius above average temperatures invades a region stretching from Northeast Greenland to the North Pole and back to the isle of Novaya Zemlya in Russia.

Overall, the sea ice in this region is much weaker than normal. Volume is greatly thinned as both the relentless heat influxes and strong sea ice export through the Fram Strait this Winter has leeched the area of thick ice. Most sea ice measures show a loss in concentration and volume for this area. But we’ll know more as the Earth tilts back toward the sun and visible satellite coverage again takes in the entire Arctic.

Given atmospheric changes taking place with Spring — where Continental and lower Latitude warming hold greater sway over atmospheric circulation — this may be the last burst of heat we see through this zone that produces such high temperature anomalies. A grand finale for the record warm Arctic Winter of 2016.
Warm North Atlantic Winds
(Warm North Atlantic Winds are predicted to blow into the Arctic yet again on Saturday, March 12. These winds will push temperatures over a broad region of sea ice to near freezing, driving such anomalously warm temperatures all the way to the North Pole. Image source: Earth Nullschool.)

To be clear, long range model forecasts do identify far above average sea surface temperatures and above average 2 meter air temperatures for this region through Spring and on into Summer. However, the Arctic overall is not as capable of producing such high temperature anomalies during Summer as it is during Winter when the human supplied greenhouse gas overburden and the related warming of the oceans holds a much stronger sway — re-radiating an insane amount of heat throughout the long polar night.
High Arctic Temperature Anomalies Predicted to Fall-off For a Short While, Melt Potential Through Summer Looks Rather Bad

To this point, it appears the Arctic may be in for a brief respite on the 3-7 day horizon. GFS model runs indicate overall cooling for the region above the 66 North Latitude line and temperatures above 80 North may see their first period of near average temperatures since late December of 2015. This respite for the High Arctic, though, comes as temperatures in the Sea of Okhotsk, the Bering, and along Hudson Bay are expected to warm.

Arctic Sea Ice Area lowest on record
(Arctic sea ice area remains at record low levels during March of 2016. Image source:Cryosphere Today.)

It’s a mixed signal that may continue some of the very slight Arctic sea ice rejuvenation we’ve seen during March — with sea ice area still in record low territory, but with sea ice extent edging back to second lowest on record and just slightly above 2015.
To be clear, we’re at a very low launching pad for the start of melt season in 2016. Record low or near record low sea ice volumes in February and continuing record low area show that sea ice resiliency is pretty terrible at this time. Furthermore, Northern Hemisphere snow cover totals also at or near new record lows hint that warming of the land masses surrounding the Arctic may be very rapid come mid to late March and throughout April. To this point, 10 day Euro model runs show a tendency for rapid warming over the Northwest Territories, Alaska, the Bering Sea, the Sea of Okhotsk, the East Siberian Sea, and far Eastern Siberia during this period even as the thaw line pretty much everywhere jumps swiftly northward.

A fading record El Nino in the Eastern Pacific will also tend to result in ample excess Equatorial heat heading northward. As a result, the overall risk of strong sea ice melt through the Summer of 2016 remains very high.

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