Sunday, 20 November 2016

Extreme polar warming and ice melt

Pair of Arctic Storms Sparked Severe Polar Warming, Sea Ice Melt for November 2016

 
Folks — we’re in a climate emergency. Tell everyone you know. 
— Eric Holthaus

There are weather and climate records, and then there are truly exceptional events that leave all others in the dust. Such has been the case across Earth’s high latitudes during this last quarter of 2016… 
— Bob Henson at WeatherUnderground


Global warming doesn’t care about the election. 
— Dr Gavin Schmidt of NASA GISS
*****
The dramatic Arctic warmth and related damage to sea ice continued today. It’s a situation that Bob Henson at Weather Underground has aptly dubbed ‘the crazy cryosphere.’ But from this particular observer’s perspective, the situation is probably worse than simply crazy. It appears that we are now in the process of losing an element — Arctic sea ice — that is critical to the integrity of seasonality as we know it.

extreme-heat-arctic
(Extreme Arctic warmth was drawn in by two warm storms — one running north from the Barents on November 14. Another emerging from Kamchatka on November 16 and 17. Warm storms have, during recent years, run up along high amplitude waves in the Jet Stream and into the Arctic during both summer and winter — with apparent strong impacts to sea ice [see NASA video below]. Image source: Climate Reanalyzer.)

On November 17, according to Arctic sea ice expert Zack Labe, the Arctic Ocean actually lost about 50,000 square kilometers of ice coverage. This would be odd on any given November day — which typically sees a trend of rapid freeze as the Arctic cools down into winter. But it is particularly strange considering that the Arctic Ocean is presently in a severe sea ice deficit of around 700,000 square kilometers below previous record lows. One that follows on the heels of both a very warm October and an exceptionally warm November for the Polar region of our world.

These losses occurred just one day before overall temperature anomalies for the climate zone above 66 degrees North Latitude went through the roof. For today, according to Climate Reanalyzer, temperatures for the entire Arctic spiked as high as 7.26 degrees Celsius above average. This occurred even as readings near the North Pole hit to near or above freezing in some locations.
image
(Warm Storm running up through the Fram Strait on November 14 — an event which flooded the high Arctic with abnormal late fall heat. Image source: Earth Nullschool.)

And though these warming events have been widely reported in climate media, what has not been reported is the fact that a pair warm storms similar to the one that hammered sea ice and brought North Pole temperatures to above freezing during late December of 2015 were also the triggers for the present Arctic Ocean warming event.
Such intense warm air invasions can have a dramatic impact on sea ice. According to NASA,last year’s late December warm storm event resulted in considerable ice thinning and melt over the critical sea ice region surrounding the North Pole. Ice in the Barents was reduced by 10 percent. Sea surface temperatures in some locations jumped to 20 degrees (F) above average. And throughout the month of January, there was little rebuilding of sea ice into the recently melted regions.

Approx 3-day sea ice loss in JAXA now 140,000 km^2. Nearly 1 million km^2 below past record low

(A recent NASA study found that warm storms can have a serious impact on sea ice. And for both 2015 and 2016, this appears to be the case.)
This year’s warming event was also accompanied by a storm running north out of the Barents. On November 14, a 955 mb storm ran directly up through the Fram Strait. It ushered in warm, moist winds from the south which then spread northward over the Central Arctic — bringing with them above freezing temperatures. On November 16, a 966 mb storm crossed over Kamchatka. It subsequently weakened. But it still possessed enough oomph to pull in a strong plume of warmth and moisture as it entered the Arctic Ocean near the region of the East Siberian Sea. And the result has been a flood of warm air coming in from the Beaufort and East Siberian Sea to meet with the similar onrush coming from the Barents. The result is the huge Polar heat spike that we see today.
Following a very warm October, this is a kind of insult to injury situation for the sea ice. And though temperatures are expected to fall back a bit over the coming week in the High Arctic, atmospheric and ocean conditions running into December seem to favor the potential for more warm air influxes to this fragile climate zone.
UPDATE: On November 19, it had become apparent that significant sea ice losses were ongoing in the Arctic. According to the JAXA sea ice monitor, about 140,000 square kilometers of sea ice had been lost over the period of November 16 through 18. As Arctic Ocean ice typically freezes quite rapidly during November, such counter trend losses are highly extraordinary. Now, sea ice in the Arctic, according to JAXA is 995,000 square kilometers below the previous record low set during 2012.

NSIDC shows similar losses in the sea ice extent monitor for the period of November 16-18. In total, 170,000 square kilometers of ice has been lost over the three day period and the total departure from the previous record low in 2012 is now 702,000 square kilometers.

These losses are quite extensive and, in many ways, are worse that those that occurred following the December 27, 2015 warm storm event.
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Hat tip to June

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