Looking for winter weirdness 6

I wasn't expecting another instalment in this year's series of blog posts on Winter Weirdness, extreme weather events that could be linked to the decline in Arctic sea ice. It's not even winter anymore officially. But as spring has been revoked in large parts of Europe, and the atmospheric blocking that is causing it is being linked to Arctic sea ice as a potential cause, I figure it's a fitting end for the series.

One of the first articles alluding to the link, appeared on the Guardian's website on Monday: Scientists link frozen spring to dramatic Arctic sea ice loss. Stefan Rahmstorf, professor of Physics of the Oceans at Potsdam University, went further, writing a blog post showing the similarities between the current event and modeled projections in recent research that investigated the influence of Arctic sea ice loss on atmospheric patterns. Lepus Universalis Eli Rabett was so kind as to translate Rahmstorf's blog post to English:

Melting Ice and Cold Weather

The media are debating if the decrease in  Arctic ice  is related to this winter's cold weather in Germany. This post discusses the most recent current research about this including the most important figures from relevant studies.

First, what does the unusual temperature distribution observed this March actually look like? Here is a map showing the data (up to and including March 25, NCEP / NCAR data plotted with KNMI Climate Explorer):

Freezing cold in Siberia, reaching across northwestern Europe, unusually mild temperatures over the Labrador Sea and parts of Greenland and a cold band diagonally across North America, from Alaska to Florida. Averaged over the northern hemisphere the anomaly disappears - the average is close to the long-term average. Of course, the distribution of hot and cold is related to atmospheric circulation, and thus the air pressure distribution. The air pressure anomaly looks like this:

There was unusually high air pressure between Scandinavia and Greenland. Since circulation around a high is clockwise [anticyclone], this explains the influx of arctic cold air in Europe and the warm Labrador Sea. 

Arctic sea ice

Let us now discuss the Arctic sea ice.  The summer minimum in September set a new record low, but also at the recent winter maximum there was unusually little ice (ranking 6th lowest - the ten years with the lowest ice extent were all in the last decade). The ice cover in the Barents sea was particularly low this winter.  All in all until March the deficit was  about the size of Germany compared  to the long-term average.

Is there a connection with the winter weather?  Does the shrinking ice cover influence the atmospheric circulation, because the open ocean strongly heats the Arctic atmosphere from below?  (The water is much warmer than the overlying cold polar air.) Did the resulting evaporation of sea water moisten the air and thus lead to more snow? These questions have been investigated by several studies in recent years.

Read the rest over at Eli's, or in German at KlimaLounge.

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Update: Commenter R. Gates has a firm meteorological grasp of current events, which not only could be influenced by the state of the sea ice, but also have to do with the early breaking down of the Polar Vortex I alluded to in my latest blog post on the cracking event (Arctic freezing season ends with a loud crack). Here's his explanation in a comment below:

There are certainly two dynamics at play in the "weirding" of this winter's weather, but before discussing them, it would probably be good to understand that we are in a new regime of climate and therefore weather patterns, and thus, the weather is only weird compared to some former regime. In other words-- weird is the new norm, and it will be weird in the future not to have blocking patterns and associated extremes that come with climate change.

But back to the two big dynamics at work in this winter's NH winter. The first is of course the big SSW event that took place in early January. This event was not unlike the big SSW events of 2009 and 2006. The polar vortex was shattered and the normal westerlies over the Arctic reversed and cold air from the east has been generally circulating over N. Europe for several months. The SSW event from January, in addition to breaking down the vortex and warming the stratosphere over the Arctic, brought downwelling air actually all the way from the mesosphere down into the stratosphere and created higher pressure all the way down to the troposphere. This downwelling air from the mesosphere also affects stratospheric chemistry such that we've seen some of the lowest ozone levels ever recorded over the Arctic in the stratosphere this March. But more than that, the downwelling air (that began during the SSW of early January) lead to an AO index that fell well below -5, a level never before seen in over 60 years of records. In short, the SSW event from January has had lingering repercussions far beyond the original rapid stratospheric temperature spike. One must keep in mind that the energy or initial trigger for this event begins as an upwardly directed pulse or wave of warm air that begins far south of the Arctic in the troposphere, where it pulses rapidly up into the stratosphere and then travels at mid and upper stratospheric levels before descending rapidly over the pole. The SSW of January over the Arctic had its energetic origins over south Central Asia in December.

But the other influence in this winter's weather is certainly the low sea ice level, and with it, the changes in atmospheric circulation in general that Dr. Francis and others are studying so closely. It might seem natural to try and associate SSW events and the atmospheric changes brought about sea ice decline but there doesn't seem to be a link. However, that does not mean that they might not have some synergistic interplay. For example, if you get a blocked atmosphere as the result of lower sea ice (and the resultant change in thermal gradient between equator and pole) and an SSW event does come along, that blocked atmosphere could enhance the effects of the SSW, i.e. the two combined could certainly result in exactly what we saw a few weeks back with an AO index that was off the (bottom) of the chart, literally.

Regarding the easterly wind anomaly over higher latitudes of the NH that began as part of the January SSW event, this chart shows this quite clearly:

The easterly anomaly began with the SSW event and has brought colder Siberian and Arctic air masses consistently from the east over Europe since Janauary. The higher pressure over the polar regions also had its origins with the January SSW event:

If SSW's are not caused by lower sea ice, but their effects are potentially enhanced by them, then we would expect more extreme effects from SSW's in future NH winters as alterations in the jet stream and blocking effects from lower sea ice levels enhance SSW effects.

Finally, the very low AO, which coincided with the cracking of MYI as reported so well by A-team and others, may certainly be one example of the an enhancement of January's SSW effects. The descending air and higher pressure over the Arctic brought about a stronger anti-cyclonic rotation of that lasted over a longer period. This is the same easterly anomaly as discussed and linked to above. The ice may have been primed to crack by being thinner anyway, but the sustained high pressure and anticyclonic action worked over a long period and helped to enhance the cracking in my estimation.

The BBC put up a useful video at the beginning of the year to explain what SSWs are.

Comments

[A-Team]

The image below has extracted the cracks from ambient background using an old Indian trick called grain merge on coherent time-separated infrared imagery. While some crack intersections etc are missing, points in a field of lines are in effect a set of measure zero.

The image -- which is a representative mid-latitude chunk of the Beaufort -- contains 234,230 pixels, of which 25,190 are white (cracks). That pencils out to 10.7% of the ice being newly frozen in opening fractures. And these are just the cracks wide enough to be seen on this mid-resolution imagery (1.7 km).

This ice will never attain the freeboard of the ambient ice because ice temperatures are already rapidly warming according to the ever downshifting scale on the avhrr imagery, and so will accumulate melt pond water as the local low point, lose their solar reflectance, melt through and drain.

[Steve Bloom]

In case no one has already posted it, here's a nice NASA EO graphic and article showing surface temp anomalies 3/14-3/20. The NH jet circulation pattern is strikingly apparent. Note that the other major poleward jet excursion in the NW Pacific region is missed by the graphic, although its presence can be inferred from the relative warming in far eastern Siberia.

[John Dorsa]

A thought from A-Team's 1:05 post

We have lingered in the chambers of the sea
By sea-girls wreathed with seaweed red and brown 130
Till human voices wake us, and we drown.

[Steve Bloom]

Thanks for the link to the Greenland post from Fairfax Climate Watch, John. The extensive peripheral snow melt so early in the year is a surprise, although I suppose not a shocker.

I was especially interested to see the reference to liquid water starting to persist in the firn under the thicker snow cover consequent to warming. Somehow I doubt that the models anticipated this effect (hard to do so, to be fair). It sounds like it has the potential to greatly accelerate the rate of ice sheet melting.

Neven, I notice by way of John's link that NSIDC has started a new sub-site Greenland Ice Sheet Today, including melt graphics updated daily as well as periodic posts. Maybe a post here to help draw attention to it?

[Neven]

Steve, I will definitely post on that soon. Glad I didn't so far, because they had a glitch.

BTW, I released a couple of comments from the spam filter. I don't know what's wrong, but am getting increasingly annoyed. Spam is one thing, perfectly legitimate comments getting tagged as spam is quite another. My apologies for the inconvenience.

[wanderer]

Interesting April NSIDC- Update:
http://nsidc.org/arcticseaicenews/

[Jim Hunt]

Thanks very much for your 04:21 suggestion John:

http://marketing-dreams.co.uk/2013/03/the-mirror-crackd-from-side-to-side/#comment-1628

[Jim Hunt]

John C,

It looks like you're in with an excellent chance of providing the first correct answer to my All Fools' Quiz!

http://econnexus.org/the-economist-being-economical-with-the-truth-about-climate-change/

[Jim Hunt]

Wanderer - Interesting indeed!

Spring has sprung in the Arctic. The "Goat's head" is in plain view. "A-Team" and Neven are however conspicuous only by their absence!

[Climate Changes]

@ wanderer
"The month was also notable for continued fracturing of the ice cover in the Beaufort and Chukchi seas north of Alaska, as seen in a new animation by the NASA Earth Observatory ."

What I find interesting is that no mention is made of the rest of the Arctic basin. There were/are cracks in Kara, Laptev and north of greenland too... pretty much everywhere you look.

[Shared Humanity]

Reading the links on the condition of the Greenland snow cover, it seems we may have our attention drawn to the growing horror on the GIS this melt season.

[Chris Reynolds]

Joint second coldest March since records began 100 years ago. The coldest March was in 1962.
http://www.bbc.co.uk/news/uk-22010852

[Espen Olsen]

Chris;

Does that mean you can get a real cold beer in the UK this season, sounds good?

[Jim Hunt]

Hi Espen,

Sounds horrible! "Real Ale" should be served "at cellar temperature 12-14 C":

http://www.camra.org.uk/beerinthepub

Getting back on topic, the coldest March in the UK for 50 years has for some strange reason coincided with a rather warm March in West Greenland, amongst other places:

http://earthobservatory.nasa.gov/IOTD/view.php?id=80804

[Chris Reynolds]

Don't know Espen, I no longer drink. :)

[Espen Olsen]

Not that I prefer cold beers, but UK is famed for "warm/flat" beers, I myself prefers Guinness, because of the albedo effect!!

[Chris Reynolds]

I do allow myself a high quality decent size bottle of cider which is consumed sparingly over the weekend of the Glastonbury Festival, so I'll be drinking this year as I watch the BBC, with the prospect of my own bed rather than a muddy tent. Festivals are best viewed at a distance.

[P-maker]

Going to a concert tonight, I had the following reflection:

With a President like this: http://www.forseti.is/media/PDF/2013_02_26_NewArctic.pdf

you may wonder, whether Monarchy is the right way forward...

[Climate Changes]

After glaring at some papers, articles and studies I'm starting to wonder if the origin of the SSW's increased intensity is the heat/energy that usually moves East across the Pacific during el Niño years. Instead, as the Walker circulation and Jet stream weaken, the energy appears to be shifting north/northeast... and onto the Arctic.... straight from the Indian/western pacific oceans. To all you pundits out there, is this possible?