Greenland 2014 Melt Season

[sidd]

At

http://polarportal.dk/en/groenlands-indlandsis/nbsp/total-masseaendring/

i see a graph of GRACE derived GIS mass loss through early 2014. Shocking, to me, is the almost nonexistent annual drop in summer 2013, as opposed to a pronounced fall every other summer for the period covered (2003 on). Why ?

sidd

[wili]

From the last paragraph of sleepy's article:

...the similarity in climate between then and now "suggests the threshold for ice sheet collapse is pretty low," according to Carlson. "We could be nearing the tipping point."

Coming on the heels of the recent WAIS study, this is rather disturbing. What does this all add up to in terms of likely and potential sea level rise in the near and not-so-near future?
____

Good point about 2013 melt season, sidd. It does put the sea ice melt in perspective, it that year was so very anomalous in terms of GIS melt. Do clouds alone explain it? Snow extent? Other factors?

[icefest]

Check your PM's Sleepy.

The biggest question now is just how fast will the melt happen and how many other ice shelf collapses can be prevented.

[F.Tnioli]

At

http://polarportal.dk/en/groenlands-indlandsis/nbsp/total-masseaendring/

i see a graph of GRACE derived GIS mass loss through early 2014. Shocking, to me, is the almost nonexistent annual drop in summer 2013, as opposed to a pronounced fall every other summer for the period covered (2003 on). Why ?

sidd

2013 was cold (generally speaking) summer. Thus temporary halting the trend of increasing amount of melt. It stayed nearly as bad as 2012 though, which was bad enough. Look at all that red all the way during 2013 (this GRACE bit is animated, if you didn't notice).

[RaenorShine]

At

http://polarportal.dk/en/groenlands-indlandsis/nbsp/total-masseaendring/

i see a graph of GRACE derived GIS mass loss through early 2014. Shocking, to me, is the almost nonexistent annual drop in summer 2013, as opposed to a pronounced fall every other summer for the period covered (2003 on). Why ?

sidd

GRACE is an old satellite (now well past its original intended lifetime) as per NOAA's report card http://www.arctic.noaa.gov/reportcard/greenland_ice_sheet.html

Unfortunately, GRACE mass loss estimates are not available for August and September 2013, when the K-band ranging system was switched off to preserve battery life.

This was asked previously about the polar portal graph on the blog also(http://neven1.typepad.com/blog/2014/05/greenland-2013-in-review.html), and Pete Williamson sent polar portal an email and got the following reply

Your question is really good, and the answer is actually quite simple: The GRACE mission is already way past the originally intended duration, but the satellites are still flying. But systems do fall out once in a while and, as an example, the 2013 summer data are unavailable due to power system problems. The 2013 summer data are thus missing from the Polar Portal GRACE figure. The linear interpolation across the summer negative peak suggests an extremely low (even no) loss summer and therefore is very misleading. We will work on a different way of representing this.

[RaenorShine]

What form of precipitation is an area experiencing? Rain, such as the rains this last week at Julianehaab, must be melting whatever fresh, high albedo snow as exists down at least to the low albedo strata experienced in recent summers.
The water may not have made it's way to the sea yet, but it must have left behind a far more susceptible surface for rapid melt. Some of the environment Canada products show rain as opposed to snow IIRC & I'm sure I recall rain having fallen as far north as Peary Land in 2012.
When normally Arctic desert regions experience rainfall the resulting melt thins glaciers and fast ice more rapidly than high temperatures.
Terry

Terry you're right it's mainly rain at the lower levels, and will be playing havoc with the albedo.

At higher levels it is still snow.  The heavier snow earlier in June had a noticeable positive affect on the albedo (which has now reversed again).

[RaenorShine]

NSIDC shows melt area increasing again, up to 30% on 24/6.

DMI shows heavy precipitation over the southern peninsular more than offsetting increased melt in the north, leaving the daily SMB loss at 2Gt (25/6)

[sidd]

Thanx for the clarification on GRACE. Clearly summer 2013  is missing, should be indicated on that graph. Saves me a bunch of time rooting thru GRACE results.

sidd

[RaenorShine]

NSIDC increased again to 35% on (25/6), just inside the 2sd range for this date.

DMI shows the precipitation moved north from the southern peninsula along the east coast. melt along the south west coast has decreased markedly, but this has been more than made up for by increased melt in the north.  the daily SMB loss stands at around 2.5Gt, below the seasonal average.

Looking at the year to date graph for Surface Mass Balance, we are tracking between the 2012 line and the 1990-2011 average.  For total mass balance (including glacier run off) the graph indicates that we have caught up with 2012 after a slow start to the year.

NSIDC shows well above average melt for the whole of June, while not matching 2012 (which had hovered around 40% melt area for most of the month), we are well above the 2013 YTD average.

[folke_kelm]

There is a very important paper in Nature Geoscience:
http://www.nature.com/ngeo/journal/v7/n7/full/ngeo2179.html?WT.ec_id=NGEO-201407

Please take your time and read it. The paper shows that refreezing meltwater is warming the ice sheet from beneath, alternating the ice flow due to lower viscosity of warmer ice.
It will be important to know the volume of the refrozen unit under the ice sheet to evaluate the transferred energy and project future developments of ice viscosity.

The mechanism of ice accretion from beneath is reported earlier from the antarctic ice sheet. I will look for the paper to post a link when i have time.

[Frivolousz21]

Does that dmi graphic show new snow/ice mass down to 1000M?

Just looking at the gfs panels from yesterday temps on the SE coast were above 0C upwards of 1500-2000M

With 480W/M2 beaming down even on the side of an ice sheet gaining that much mass in those conditions seems crazy .

[VaughnAn]

One gigaton of water that has fallen 1000 meters into the ice starting at 0˚C would be expected to raise 80 gigatons of ice 1˚C as this water freezes(provided the surrounding ice is cold enough to freeze it) plus raise another 2.38 gigatons of ice 1˚C from the heat generated from changing potential energy to kinetic energy and then to heat on the way down.  This would certainly be a major way for heat to permeate the ice sheet.  Think of it this way: This would be roughly the same heat transfer as dumping 82C water into a pan of ice and melting it.
Once the interior reaches 0˚C then every gigaton of water starting out at 0˚C falling 1000 meters should melt about .06 gigatons of ice.

[folke_kelm]

that is not entirely right because the meltingpoint of ice is dependent on pressure. under 2 km of ice the melting point of water is less than -2 centigrade.

[VaughnAn]

Kelm, you are correct. This makes the melting point even easier to reach and when it is reached the ice will melt even faster.

[RaenorShine]

NSIDC shows a very slight dip in melt area. We are still around 35% on 26/5.

DMI shows the precipitation markedly lessening from yesterday.  Melt looks to be similar, as a result daily SMB loss has increased to around 3Gt.

[RaenorShine]

No nsidc update yesterday.

The DMI SMB model showed the mass increases due to precipitation moving west. Around the edges of the sheet, melt continues, and the daily SMB loss has only decreased slightly, still around 3Gt.

[RaenorShine]

No NSIDC update again yesterday.

DMI shows further precipitation in the south, with mass loss continuing in the north, and around the edges in the south. The SMB mass loss fell again, to just over 2Gt.

[RaenorShine]

No NSIDC update again.

DMI shows the precipitation moving north again. Daily SMB loss has increased slightly to around 2.5Gt.

[RaenorShine]

NSIDC have updated, and show that melt area fell sharply from 26/6 -  30/6, with melt area now at around 25%, mainly due to a drop in the south.  Melt area is still above the average for this day of around 20% though.

DMI shows the precipitation moving north, with melt increasing slightly in the south. Overall daily SMB loss continues at around 2.5Gt.

The MOD10A1 albedo anomaly shows the affect of the recent precipitation over the south west ice sheet, with almost none showing for the SW (compared to a sea of red for the rest of Greenland - indicating the ice is darker than previous years).

[RaenorShine]

NSIDC shows a further fall in melt area to 20% of the sheet on 1/7, with very little melt across the south.

DMI shows the precipitation almost gone and melt increasing in the south again.  Net daily SMB loss of 3.5Gt on 2/7.

NSIDC seems to lag increases in melt on DMI by a day or two, so I'd of though that the met area wil be on the increase again soon, barring any further precipitation.

[Kethern]

So what will the effects of a post tropical storm be on melting?



Especially with some of the SST anomalies he is going to pass over on the way there.

[RaenorShine]

NSIDC shows a small uptick again on 2/4, to just over the 20% area mark.

DMI shows the situation almost unchanged from the previous day, with daily SMB loss continuing at just over 3Gt. 

[RaenorShine]

NSIDC shows melt decreasing a on 3/7 to under 20% of the sheet area.

DMI shows melt increasing markedly, with a new ytd record. Daily SMB loss increased to 5Gt on 4/7.

[Laurent]

Dark snow: from the Arctic to the Himalayas, the phenomenon that is accelerating glacier melting
http://www.theguardian.com/environment/2014/jul/05/dark-snow-speeding-glacier-melting-rising-sea-levels

[RaenorShine]

NSIDC shows melt increasing to nearly 30% of the sheet area on 5/7.

DMI shows precipitation moving into the south (again). Net daily SMB loss has backed off to around 4Gt on 5/7.

[Frivolousz21]

GIS melt extent will likely reach 50% this week maybe 60% for a day.

[RaenorShine]

DMI shows the precipitation has moved off again, with the melt pattern similar. The daily SMB mass loss increased to around 5Gt on 6/7, just under the ytd record from a couple of days ago.

[Shared Humanity]

DMI shows the precipitation has moved off again, with the melt pattern similar. The daily SMB mass loss increased to around 5Gt on 6/7, just under the ytd record from a couple of days ago.

I would call this "peak melt" for the season instead of "ytd record" to avoid confusion.

[silkman]

Minus 4C at Summit right now. Widespread melt is to be expected at lower altitudes.

[RaenorShine]

NSIDC melt area increased to around 35% on 6/7, the highest in a month, and as Friv says looking at yesterdays DMI data (below), I can only see it going higher.

DMI shows melt increasing around the whole coast on 7/7, and also precipitation arriving in the south (Kethern - the remnants of Hurricane Arthur?).  Net daily SMB loss rose to 6Gt, a new peak melt loss for the year.

Silkman, yes July is the peak melt month historically for Greenland, this years melt season is above the average (and 2013) but is really unlikely to catch the 2012 surface melt at present.  DMI are showing the Year to Date Total Melt Loss(SMB + Glacial Loss) to be a shade higher than 2012 at present. This can only be due to increased glacial speeds due to the lower SMB loss. Interesting times.

[RaenorShine]

I would call this "peak melt" for the season instead of "ytd record" to avoid confusion.

No problem I've started that above, suggestions etc always welcome!

[RaenorShine]

NSIDC shows a fall in melt area on 7/7 to around 30% of the sheet.  Last time I predict anything!

DMI shows really heavy melt along the west coast, increasing the net daily SMB loss to over 8Gt on 8/7, another peak melt loss for the season. @greenlandicesmb says of 7/7 map on twitter 'Well into ablation season #Greenland. Anomalously cold weather but melt rates high,'

[RaenorShine]

NSIDC melt area is back up again to around 35% of the sheet area on 8/7.

DMI show that the melt in the south hass lessened significantly, and with increased precipitation, daily SMB loss has fallen back to 5Gt.

The recent snow in the south over the past cpouple of weeks has also affected the albedo of the southern ice sheet, removing large areas of negative (darker) anomaly.

[SteveMDFP]

On my evening's MODIS perusal, I spotted an odd-looking feature on Greenland's ice sheet, south of Jacobshavn.  Two images, 48 hours apart.  It would have been terrifying to be in this location as this melt river formed.  I don't know if this is a rare find:

[Sonia]

... an odd-looking feature on Greenland's ice sheet, south of Jacobshavn...

A cloud edge?

[Andreas T]

comparing the image shown by Sonia with the one posted by Steve you can see the clound edge has moved slightly south keeping the shape of its shadow. Hard to see how a river could do that same thing .

[RaenorShine]

NSIDC melt area is on the increase again to just under 40% of the sheet on 9/7.

DMI shows the precipitation decreasing, with melt similar to the day before.  Daily SMB loss increased to 6.5Gt (10/7).

[SteveMDFP]

... an odd-looking feature on Greenland's ice sheet, south of Jacobshavn...

A cloud edge?

Quite right.  A reminder to look at other bands before jumping to conclusions. 
Nevermind.  ;-)

[RaenorShine]

NSIDC melt area fell slightly to around 35%.

DMI shows a similar patter to yesterday. As often happens, as the fresh snow a couple of days ago is burned off, melt steadily increases as the albedo falls back. Daily SMB loss increased to 7Gt.

[RaenorShine]

NSIDC melt area fell again to around 30% on 11/7.

DMI shows a very similar pattern again. Daily SMB net loss fell slightly to 6Gt on 12/7.

[RaenorShine]

NSIDC melt area fell again, to under 30% of the total sheet area on 12/7.

DMI shows melt decreasing in the north, with a fairly large area of light precipitation. Daily SMB loss fell to 5Gt.

[RaenorShine]

NSIDC melt area is almost unchanged at just under 30% of the sheet's area (13/7).

DMI's SMB model shows a significant slow down in net loss, with decreased melt and precipitation in W Greenland.  Daily SMB loss fell to 3Gt, under the 1990-2011 average for today.

[RaenorShine]

NSIDC melt area fell to around 25%, just over the 1981-2010 average for 14/7.

DMI has less melt and more precipitation again, with the daily SMB loss falling to 2Gt (15/7).

[RaenorShine]

NSIDC melt area fell again to only 20% of the sheet (15/7).

DMI has a similar pattern to yesterday, with precipitation in the East, and melt lessening again.  Daily SMB loss fell again to 1Gt, which is around the lowest for the date since 1990. 

The lack of melt over the past couple of days is now clearly visible in the YTD graph. This year is now over 100Gt behind 2012 in terms of SMB, a record melt is unlikely. It should still be below the 1990-2010 average minimum, which only needs another 25Gt or so to be beaten.

[LRC1962]

@RaenorShine: If I recall Greenland had a very intense High parked over it for most of the melt season of 2012. On top of that major deposits of soot from big fires in Quebec if I remember. This year there has been a mixed bag of weather mainly on the cool side, so the melt should not be that big a surprise. Although we can say that something is still happening to the ice as the caving of the glaciers has not seemed to be showing signs of a slow down this year (I think anyway)

[RaenorShine]

@RaenorShine: If I recall Greenland had a very intense High parked over it for most of the melt season of 2012. On top of that major deposits of soot from big fires in Quebec if I remember. This year there has been a mixed bag of weather mainly on the cool side, so the melt should not be that big a surprise. Although we can say that something is still happening to the ice as the caving of the glaciers has not seemed to be showing signs of a slow down this year (I think anyway)

Yes, 2012 was a very abnormal year for surface melt, if we match or exceed that regularly we are in trouble.

Even though its been a cool year net surface melt is still above average, probably due to the albedo anomaly.

Also as you say, the glaciers have not slowed down, but look to have actually sped up vs 2012. DMI's Total Mass Change (SMB + Glacial Calving) is running slightly ahead of 2012 (http://polarportal.dk/en/groenlands-indlandsis/nbsp/total-masseaendring/). As SMB is below 2012, DMI's model shows Glacial Calving has more than made up this difference.

How much of the increase in Glacial Calving is a hangover from 2012 I don't know, but the winters are no longer resetting the ice sheet to a neutral state.

On the current drop, @GreenlandSMB (a DMI twitter account said :

Unusually cold weather and snowfall giving close to positive #SMB values this week

[RaenorShine]

NSIDC melt area is unchanged at 20% (16/7).

DMI shows the precipitation lessening, increasing the net mass loss. Daily SMB loss increased to 3Gt (17/7)

[Frivolousz21]

Melt area is going to slowly climb and should go back up into the 30-40%+ by day 3-4 and stay there.

[Buddy]

Looks like we may get to a 2014 season high melt percentage on Wednesday or so.  May get to 50% - 60%..

[RaenorShine]

NISDC Melt area rose to around 25% on 17/7, and fell slightly again on the 18/7.

DMI shows melt increasing and precipitation decreasing again on 18/7. Daily SMB loss increased to 5Gt.