Greenland - What Do We Know, What Is The Long Term Future And Is There Any Evidence Of A Melt Out?

[pottyprof]

Why? I've been told we are in a cooling period.

Not sure what you've been reading knocker? There is nothing I've been reading recently that says that. Next you'll be telling me we lived through the end of the world....

[Gray-Wolf]

Tell you what LG, losses less than the 2010 mega melt next year and I'll stay quiet on Greenland's mass loss for 5 years.

Losses greater than this years exceptional melt and you accept that the changes are well beyond what nature is able to conjure up alone?

Deal?

[knocker]

where there’s fire there’s smoke

…

Wildfire, increasing with climate change [1, 2, 3], deposits increasing amounts of light-absorbing black carbon [soot] on the cryosphere [snow and ice], multiplying the existing heat-driven ice-reflectivity feedback [a.k.a. albedo feedback].

Sifting through data from NASA’s Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) revealed smoke clouds near, over, and even in contact with Greenland.

http://www.meltfactor.org/blog/?p=766

[keithlucky]

Why? I've been told we are in a cooling period.

On December the 29th Greenland recorded -78f thats 5f colder than ever recorded before http://www.summitcam...status/weather/ Edited January 2, 2013 by keithlucky

[Gray-Wolf]

So the extremes there are becoming ever wider then?

I've been noting just how many warm incursions the early winter has brough to the south and west of Greenland so I think we'll see an interesting set of data from the winter. The H.P. anom, and the cold dry it facilitates over winter, is balanced by the heat it allows over summer. We seem to be seeing the same across sections of Russia and China a.t.m. but both those places have also been hammered , over summer, by similar anom. H.P. systems and the dry and extreme heat they bring with them.

Odd that across the water from N.Greenland Svalbard has once again had rain in late December and was challenging last years record high temp for December?

[songster]

On December the 29th Greenland recorded -78c thats 5c colder than ever recorded before http://www.summitcam...status/weather/

Rubbish. Temperature was -61c, rising to -53c

http://www.wunderground.com/history/station/04416/2012/12/29/DailyHistory.html?req_city=NA&req_state=NA&req_statename=NA

I think you misread the Fahrenheit value as Celsius. A little more attention to detail might be fruitful next time you're looking for sources.

[Devonian]

On December the 29th Greenland recorded -78f thats 5f colder than ever recorded before http://www.summitcam...status/weather/

I think Mr Goddard said five degrees above, but he did get the scale right. Edited January 2, 2013 by Devonian

[Gray-Wolf]

Do I get the feeling that some folk are getting desperate to see a Squirrel?

[knocker]

Here's a movie showing the melt extent over Greenland for 2012, 2010 (the previous record) and the 1981 - 2010 mean that Mauri Pelto put together. Illustratesit very well methinks.

http-~~-//www.youtube.com/watch?feature=player_embedded&v=brKVLQO-100

http://www.greenlandmelting.com/

Edited January 4, 2013 by knocker

[knocker]

Future projections of the Greenland ice sheet energy balance driving the surface melt

Abstract. In this study, simulations at 25 km resolution are performed over the Greenland ice sheet (GrIS) throughout the 20th and 21st centuries, using the regional climate model MAR forced by four RCP scenarios from three CMIP5 global circulation models (GCMs), in order to investigate the projected changes of the surface energy balance (SEB) components driving the surface melt. Analysis of 2000–2100 melt anomalies compared to melt results over 1980–1999 reveals an exponential relationship of the GrIS surface melt rate simulated by MAR to the near-surface air temperature (TAS) anomalies, mainly due to the surface albedo positive feedback associated with the extension of bare ice areas in summer. On the GrIS margins, the future melt anomalies are preferentially driven by stronger sensible heat fluxes, induced by enhanced warm air advection over the ice sheet. Over the central dry snow zone, the surface albedo positive feedback induced by the increase in summer melt exceeds the negative feedback of heavier snowfall for TAS anomalies higher than 4 °C. In addition to the incoming longwave flux increase associated with the atmosphere warming, GCM-forced MAR simulations project an increase of the cloud cover decreasing the ratio of the incoming shortwave versus longwave radiation and dampening the albedo feedback. However, it should be noted that this trend in the cloud cover is contrary to that simulated by ERA-Interim–forced MAR for recent climate conditions, where the observed melt increase since the 1990s seems mainly to be a consequence of more anticyclonic atmospheric conditions. Finally, no significant change is projected in the length of the melt season, which highlights the importance of solar radiation absorbed by the ice sheet surface in the melt SEB.

http://www.the-cryosphere.net/7/1/2013/tc-7-1-2013.pdf

[knocker]

Quite an interesting video for the uninitiated like myself.

http://johnwegroves.com/2011/12/01/final-ish-thesis-entry/

[Gray-Wolf]

http://environmentalresearchweb.org/cws/article/news/51955

This puts things into crisp focus.

With the recent papers on much larger sea level rises we are already beginning to see why we should take such warnings seriously.

[knocker]

I suspect the tipping point is long gone GW.

[knocker]

I can't remember whether I posted this before.

The unique melting at Summit: a microwave perspective.

The plot below shows the passive microwave brightness temperature time series over Summit recorded between 1979 and 2011 (the ensemble of gray lines) and the time series recorded during 2012 (black thick line). The ensemble clearly shows that things are relatively stable at Summit, with relatively small interannual variability

The plot also shows that the event of July 2012 s unique for the satellite era (1979 - to date) and it lasted for a few days. For those who are not expert in passive microwave remote sensing: as the liquid water appears, the recorded signal jumps to high values, suddenly. This kind of change (sudden and strong) can be related only to the appearance of liquid water within the snowpack as other changes in the physical properties of the snowpack would produce either a weaker signal or would have a different timescale. Note: this sensitivity of microwaves to water is the same physical principle through which we are able to cook our food using microwave ovens !

http://www.greenland...erspective.html

Edited January 11, 2013 by knocker

[pottyprof]

So what does the sudden below average readings mean? Or is that just put down to an error?

[Devonian]

So what does the sudden below average readings mean? Or is that just put down to an error?

I have asked the author of the post a question about this and I will post the answer here when, or if, I get one. Edited January 12, 2013 by Devonian

[pottyprof]

Thank you.

[songster]

I believe it's because ice has a lower signature than snow. The meltwater from the thaw pulse refreezes in this case as a thin layer of ice a few cm under the surface, which may be visible to the microwave sensor. Additionally, the melting alters the structure of the surface snow itself, rounding off all the sharp angles of the ice crystals - this too may have some effect.

[Devonian]

I believe it's because ice has a lower signature than snow. The meltwater from the thaw pulse refreezes in this case as a thin layer of ice a few cm under the surface, which may be visible to the microwave sensor. Additionally, the melting alters the structure of the surface snow itself, rounding off all the sharp angles of the ice crystals - this too may have some effect.

Cheers , sounds likely.

[songster]

To be clear, I'm not the author of the post!

[knocker]

I believe it's because ice has a lower signature than snow. The meltwater from the thaw pulse refreezes in this case as a thin layer of ice a few cm under the surface, which may be visible to the microwave sensor. Additionally, the melting alters the structure of the surface snow itself, rounding off all the sharp angles of the ice crystals - this too may have some effect.

I was thinking along similar lines. I was going to ask the author but I see D has already done so.

[Gray-Wolf]

We must have someway of recognising the 'reorganisation of ice crystals' or we would not know how much the snow layer is 'soaking up' recent melt at lower levels these days?

[knocker]

Abstract. A map of Greenland in the 13th edition (2011) of the Times Comprehensive Atlas of the World made headlines because the publisher's media release mistakenly stated that the permanent ice cover had shrunk 15% since the previous 10th edition (1999) revision. The claimed shrinkage was immediately challenged by glaciologists, then retracted by the publisher. Here we show: (1) accurate maps of ice extent based on 1978/87 aerial surveys and recent MODIS imagery; and (2) shrinkage at 0.019% a^−1 in ~50 000 km² of ice in a part of east Greenland that is shown as ice-free in the Times Atlas.

http://www.the-cryosphere.net/6/533/2012/tc-6-533-2012.pdf

[Gray-Wolf]

Sadly it looks to me (and I'm no expert!) that the map is already inaccurate? When you look at Peterman it still has last year calve attached! I'd imagine that we would also need to move the east coast snow line a bit after last years melt?

I'm being a bit of a pedant but mainly to highlight that changes to the ice cover now appear to alter yearly. If the current rate of doubling continues then the Times map will be accurate soon enough!!!

[knocker]

Some more on this subject.

Scientist Seeks Connection Between Fire and Ice in Greenland

Are wildfires speeding up ice melt in Greenland? Jason Box, founder of the Dark Snow project, is taking up a collection to find out.

Last summer, record-setting wildfires raged across Colorado and New Mexico. It was the third most devastating wildfire year on record in the U.S. Warmer and drier temperatures in recent decades has also led to increased fire activity in the Arctic tundra. The Anaktuvuk River fire in Alaska in 2007, for example, burned 401 square miles, an area the size of Cape Cod. It was the largest tundra fire ever recorded.

While forests and grasslands burned, the Arctic melted. Greenland's ice sheet melted at a faster rate than scientists had ever observed, with 90 percent of the mass thawing in July.

http://www.pbs.org/newshour/rundown/2013/01/scientist-seeks-donations-to-fund-greenland-research.html