The untold drama of Northern snow cover

Do we have time for another record while Arctic sea ice records are falling around us like ripe plums? I guess we'll have to make time. M. A. Rodger, who runs the Marclimategraphs page, sent me this guest blog concerning record snow anomalies:

The untold drama of Northern snow cover

When considering the impact of climate change on polar regions, the star of the show has always been Arctic sea ice. Playing supporting roles are the Greenland ice cap and Antarctica. Yet one actor in the drama remains badly overlooked: the snows that cover our Northern continents.

In June 2012, for instance, it was reported that Northern Hemisphere Land Snow Cover had broken a record. The June snow anomaly was the lowest figure for June in the whole 45 year record, besting the previous record set in 2010 by 1 million square kilometres. This statement, reported as the last item in the US NSIDC's first July Arctic Sea Ice News & Analysis bulletin understandably never gained great widespread coverage.

Yet this summer's Northern snow cover presents a far more dramatic story that surely deserve greater prominence. For a start, June 2012 snow cover was not just the record of June. Excluding Greenland with its ice cap, the June 2012 anomaly was the record for all months in the entire 45 year record. The anomaly stood at 5.74 million square kilometres, pipping the December 1980 record by 0.13 million square kilometres, although this again is hardly front page news.

It is only with analysis of the changing anomaly through the year that the true drama of the declining snow cover can be seen. At the height of this summer's melt, 2012 was 8.5 million sq kilometres ahead of the 1972-1979 average. This is a full month advance in the melt over a 27 year period. (That is twice the advance seen over recent decades in the UK's 250 year-long phenological record which is itself dramatic enough). Another way of visualising this early melt is that the average snow limit at the height of the melt season is now a whole 500 miles further North than it was 27 years ago.

And what is most dramatic is that this process is visibly accelerating. The average retreat North over the last 27 years, since the mid-1970s, is 18 miles per year. Since the mid-2000s it is 38 miles. In this last dramatic year, at the height of the melt season, the snow has been melting away 71 miles further North than in any other previous year.

The decline for Northern Hemisphere Land Snow Cover is just as dramatic and just as consequential as the Arctic sea ice decline. We ignore it at our peril.

Comments

[OldLeatherneck]

Neven,

The rapidity at which climate changes are occuring, it may not be too many years until you have to change the name of your blog to:

Neven's Arctic Sea "Water" Blog

[Seke Rob]

In a few weeks we'll know how August and week 36 panned out in snow-off. Then there will be a chance to see if the lowest residual of week 31, see https://sites.google.com/site/allthingsclimatechange/snow-cover is bested, noting that snow did come down in places end of August 2011. Lots of more vapor meeting cold air and the recipe is made.

[Chris Reynolds]

OldLeatherNeck,

I know you're joking, but seriously. If we are on a fast path to a seasonally sea ice free state this decade then the changes thereafter will be just as worthy of analysis as what's happening now. Especially as we see the secondary impacts of that shift.

M.A.Rodger,

Thanks for the post. It will be interesting to see if there is another rapid snowline advance in Siberia this year. That could lead to another winter like 2009/10.

[Kevin McKinney]

Or "The Blog Formerly Known As..."? Again, joking about the serious...

But thanks, MARodger, for pointing out another story that's being ignored, more or less. Well, apart from the usual suspects crowing about the (moderately, by historic standards) big positive anomaly in 2010. Funny how they are silent now. Anyway, the Rutgers anomaly graph certainly provides good perspective.

Snow cover (and the lack thereof) affects albedo, too...

[Greg Wellman]

At a rough guess, the albedo forcing from a 6 million sq km snow deficit for NH June would be significantly more than a 2 million sq km arctic ice deficit. However the snow deficit is shorter lived ... they are probably comparable over NH summer. Does anyone know if this has been well quantified?

[Hans Verbeek]

I find the 3rd graph very interesting.
My friend Paradox also writes about Northern Hemisphere Snow Cover (in Dutch): http://paradoxnl.wordpress.com/2012/08/21/juni-en-juli-2012-diepte-record-omvang-van-het-sneeuwtapijt-op-noordelijk-halfrond/

[Al Rodger]

Hans Verbeck,
There are more graphs/variation-of-graphs in Section 4 of this web page. It is still work-in-progress so the words haven't been uploaded yet, but the graphs do show the full route to that third graph (and beyond).

[Fairfax Climate Watch]

Al Rodger, great site and an excellent compilation. You made it? if so, I noticed a typo in the N20 graph...(should read "Nitrous Oxide" instead of "Nitrous Dioxide."

[LRC]

http://nsidc.org/arcticseaicenews/2012/01/positively-arctic-arctic-oscillation-switches-phase/
Explains part of what happened.
Another issue was that I seem to remember that at the same time as the arctic had those very cold temperatures there were also some very big snow storms in the same area. Wouldn't that insulate the new ice from getting thicker and could it also fool the satellites into seeing thicker ice then there actually was?

[Al Rodger]

M. Owens,
Thank you for spotting that.

[Glacierchange.wordpress.com]

The most striking change to me over the last three years is not how low summer snowcover has been, but the precipitous drop from high values during the winter to record low values. The only way to lose snowcover is to melt, and what this says loud and clear is that this is the biggest snow melt off spring's of 45 years. This is something that struck me in a post I did in 2010 /a> and which we discussed at length at the 2010 Eastern Snow Conference.

[Lanevn]

It is funny, but current snow cover from Cryosphere Today is larger than in any other year since they provide this info (2005).

[Seke Rob]

It was predicted... more vapor meeting cold air, a feedback function, but which way it's going to swing out. Rutgers will be bringing out the August figures in the coming days. Previous years also display an uptick in late August. But, can you give me a link of data or chart that you're looking at over at Atmos/CT. I'm seeing a long rim on Baffin Island and other CAA parts.

[Lanevn]

Sorry, don't know any new places, just saw at that maps http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=09&fd=04&fy=2005&sm=09&sd=04&sy=2012 Not only Baffin - Svalbard, Severnaya Zemlya and etc also have more snow cover than usual.

[Seke Rob]

Rutgers August Month+Weekly are in, so it was time to update the some graphs:

4 Seasons: http://i137.photobucket.com/albums/q210/Sekerob/Climate/SnowCoverSeasonNH.png

And the 2 charts the they do, for whatever reason, do not publish on their web, though they once were there:

Snow June/July/August Summer Season
http://i137.photobucket.com/albums/q210/Sekerob/Climate/Snow_Cover_Summer.png

Snow June/July/August Summer Season Anomaly
http://i137.photobucket.com/albums/q210/Sekerob/Climate/Snow_Cover_Summer_Anomaly.png

The seasonal average dropped half a million km square to an all time Rutgers low [since 1966] of 3 million. The remarkable numbers are 8 weeks of an unmoving EurAsia at 123,065 km^2... guess there the same rule as with Greenland applies... glacial surface. The island showed an dip to 1998 level at 1.911 million km^2, http://i137.photobucket.com/albums/q210/Sekerob/Climate/Snow_Cover_Season_Greenland.png where extent is most always reported as 2,156,741 (about week 35 to 24 the next year). Really wonder, is that summer GIS really 1.9 million 10 meter thick ice minimum?

There was snow fall in North America excl. Greenland [not a mm in EurAsia, noted as stuck to 123,065]. The last 6 weeks (30-35)

30 76827
31 36259
32 368441
33 484609
34 122638
35 281064

Food for thought.

Oh we went to the Fest of Grapes and Baccus today in Citta St.Angelo. A windsor said the sugar content was very high this year, "Ottimo". Those not suited for wine did very well and indeed the basket we got tasted as the Dutch would say "mierenzoet" [too sweet for my taste].

[AbbottisGone]

So, has the negative trend continued on Northern Hemisphere snow cover?!!?

[Neven]

AiG, there's a graph for 'decline in spring snow cover' on MA Rodger's website that runs until Feb 2015.

Here's a bar graph for Spring with trend line from Rutgers University Global Snow Lab. And here's Fall and Winter.

As you can see the latter two have upward trends, which probably has to do with all that open water at the end of the melting season dumping moisture in the atmosphere. Still, this negative feedback is quickly overcome in Spring and Summer. I'm still surprised at that.

But maybe Spring/Summer snow cover has now reached a limit, I don't know. It'd be interesting to see if the snow line has retreated further North.