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ThE SnYpEr AzZ

It hadn't occurred to me that there would be so much debris and sediments ripped out of Greenland by the raging meltwater. This will widen channels and speed up glacier movements year-round and could be a significant positive feedback for GIS disintegration.

Rob Dekker

This chart about the albedo changes over Greenland had me do a few back-of-the-envelope calculations.
If albedo over Greenland changes by 1%, then 1% more of its average irradiance would be absorbed by the ice surface. Over a three-month period (say May through July) that would lead to about 14 Gton extra melt over the 1.7 million km^2 ice sheet.

In reality, looking at the charts from the 'Dark side of Greenland' post, it seems that Greenland on average reduced some 3 % albedo (more at lower elevations, less at higher elevations). If that extra heat goes to melting ice, we could expect an extra 42 Gton ice loss this year due to the albedo effect alone.
Of course, this number will be larger for areas staying above 0 C for longer than 3 months, and lower for areas that stay above freezing for less than 3 months.
Still, it gives a ballpark estimate for what we are experiencing here.

Doug Bostrom

Can't help but wonder about destruction under the ice, seeing that river.

Excellent imagery of this area on Google map/Earth; search Kangerlussuaq.

James Benison

This year's Greenland ice melt appears to be blowing all previous records off the hinges.

I don't spend too much time focusing on a single year's Greenland melt. Once the arctic sea ice is gone that pesky "heat of fusion" thing with the ice that keeps temperatures "beer cold" will cease to exist. Then arctic temps will skyrocket, exactly as the Pliocene temperature proxies say that it will with 400ppm of co2.

Neven

Latest info from Sermitsiaq (via Google Translate). Situation under control, though still a lot of water, airport safe, will rebuild bridge "making it future proof and taking into account the climatic changes."

Neven

Here's another video of a group of high schoolers measuring the height of the ice that ends up in Watson river. Apparently it dropped by 2 metres in 1 month.

Kevin McKinney

This made me remember the springs of my childhood in Sault Ste. Marie, Canada: as March progressed, so would a feedback process.

Dirt embedded in the snow would be exposed by melt. Once exposed, its lower albedo caused increased solar warming, visible in pockets where increased snow melt had carved out a hollow. This would naturally expose more dirt, und so weiter...

City snow is not the Greenland ice cap, of course...

Darren Wood

Hi any ideas on these temperature increases on the GIS as a whole in relation to sea level rise?

Glacierchange.wordpress.com

This is a dramatic melt that several field workers in Greenland I know have been amazed at. Do not get carried away with impacts on base of ice sheet or velocity. The Sundal et al (2011) paper that indicated such high flows in the long run can even reduce velocity of land terminating glaciers in this region. This is because basal water pressure is reduced after the drainage system develops to handle this water supply.

Werther

Monitoring the melt…
I’ve been noodling some with ESRL Composite today (as it’s raining cats and dogs outside).
I think this image makes perfectly clear what’s going on:
Photobucket

SST's surrounding Greenland not yet as high as 2010 but getting close. ST anomalies however are exceeding same period 2010 with 0,5 dC plus.

Glacierchange.wordpress.com

To the north a bit Tiningnilik proglacial lake is filling at record pace.

Al Rodger

Rob Dekker,
There is a number quoted for the energy absorption due to reduced albedo from the darkening 2000-11 on previous post at Meltfactor which may give a bit more confidence to your back-of-envelope calc - fence in your 'ballpark' a bit.

"Darkening of the ice sheet in the 12 summers between 2000 and 2011 permitted the ice sheet to absorb an extra 172 quintillion joules of energy, nearly 2 times the annual energy consumption of the United States (about 94 quintillion joules in 2009)."
That is enough to melt 500 cu km of ice if it was already at zero degrees and ready for melting.

One comment I would make (although I got into a dust-up last time I made it). This 0.172 zJ number, which appears on two other websites, I find used rather ambiguously. Does it apply to the size of the darkening phenomenon for years 2000-11 or the increase in size of the phenomenon over that period? My back-of-fag-packet calcs couldn't assist on sorting out which because they are both the same order of magnitude - the first about 3x the size of the second (well it was up to 2011).

Werther

Al,
As I read Box's article, it is an extra amount of heat. So that would concern the increase of the melt zone since 2000.
Mauro,
My CAD produces 45,3 km2 yesterday for that periglacial lake. When it goes, it will dump into the Illulissat fjord? Please let people be careful..
Some extra ESRL remarks:
- big bulge on 500 MB over Labrador Sea/South Greenland
- high humidity over same area on 300 MB
- low surface precip on S.Greenlands coasts

Everything points at extreme weather over the area this year.

L. Hamilton

A side note on Kangerlussuaq itself -- this settlement is the site of Greenland's main international airport, hence critical to the economy and well known to visitors.

Also known by the Danish name Sondre Stromfjord, or called Bluie West-8 when developed as an air base (foundation for the modern airport) used by the US during WW II and the Cold War.

http://img.photobucket.com/albums/v224/Chiloe/2008_August/IMG_5289b.jpg

L. Hamilton

I should have mentioned, the glacial outwash and flooding area is in the background of the picture I posted above. The ice sheet is just behind those hills.

Ole Heinrich

Oh noouhh §.-) http://www.sciencedaily.com/releases/2012/05/120529144339.htm If this is what you call "global warming" we want more of that §.-)

Werther

After having read the Van As article and interpreting figure 8 I can now imagine how the discharge two days ago could have been 3500 m3/sec.
The figure gives 0,13 km3/day as maximum discharge for 2010. The mean through the melt season was, of course, much lower. But enough for 6,6 km3/Gt that year. From a study/sheet area of 12.500 km2.
While the bridge spans max. 80 m1 and assuming a mean depth of say 5 m, the flow speed must have been around 31,5 m1/hour when that shovel was washed out.
Photobucket

Werther

31,5 km1/hour, of course!

Account Deleted

It is important to note that June 2012 in Greenland was a record warm for the last 130 years!

http://data.giss.nasa.gov/work/gistemp/STATIONS//tmp.431042500000.14.1/station.txt

Neven

Another Sermitsiaq article (via Google Translate):

Greenland will experience more violent natural phenomena with melt if the heat rises, says polar researcher.

Researcher: Magazines of meltwater on, under or in the ice sheet has increased the natural disaster in Kangerlussuaq

It was not only the last days of continuous sunshine and high temperatures in western Greenland, which has triggered the natural disaster in Kangerlussuaq.

Large stores of accumulated melt water on, under or within the ice sheet may have aggravated the violent waters.

It assesses the climate and polar scientist dr. Sebastian Mernild from Los Alamos National Laboratory in New Mexico, USA, viewing climate data:

- It seems that the high temperatures not only over the past days can produce large amounts of meltwater, which is seen at Kangerlussuaq.

- It's probably a combination of high temperatures with large stores of meltwater that is, inside or under the ice cap. It is a phenomenon in the jargon called Jøkelløb explains Sebastian Mernild.

These stores of meltwater collected in June and July, until the water pressure becomes so large that they collapse and the water begins to fosse out. It is difficult to quantify how much these magazines of meltwater is, but it is high volume, explains the researcher.

The phenomenon is not new in Greenland, with similar disasters have been seen back in the 1980s.

- It was just not as extremely violent as what we've seen. When the magazines of melt collapses, it becomes a tad more violent, says Sebastian Mernild.

The Danish climate and polar research estimates that natural phenomenon will become more frequent and more violent, as the temperature rises.

- The hotter it is, the more frequent they become, says Sebastian Mernild.

Generally, there is unusually warm at the moment in Greenland. In Narsarsuaq in south-western Greenland measured the last week, 23.6 degrees and in the capital Nuuk 20.3 degrees.

At a weather station on the highest point of the ice sheet, Summit, at 3200 meters altitude, there were 2.2 plus degrees yesterday.

Espen Olsen

It happen quite often in Iceland, the heat there is not the sun but the geysers or volcanoes, and when these contained "water tanks" burst we have the same phenomena as now in Greenland.

Steve Bloom

Hmm, unless I'm confused 3500 m^3/sec works out to .3 km^3/day, which is about triple the maximum for 2009 and 2010. It's an impressive number, but the melt reaching high onto the ice sheet is a harbinger of much worse.

SteveMDFP

One commentator on this blog mentioned that there'd been a big change in Greenland's appearance on the radar ASCAT images. I've puzzled over how to interpret these. So I decided to take the last 10 days and put them into an animated clip (my first animation effort, I have a ways to go to match Neven).

The results blew my mind and caused me to think the changes could relate directly to the sudden flooding...

Visually, the sudden change we see looks as though some internal ice dam in the ice sheet suddenly gave way and blew out the southern tip of the high-reflectance border. As though a balloon popped at the very bottom. It also looks like some outflow went out the KIV Steenstrups River.

I'll try to clean up this animation, but I wanted to share it right away:

Steve Coulter
Photobucket

Bob Wallace

That's great Steve. Could you throw in a start/stop frame into the loop?

Perhaps take your first and last frames and load them multiple times so that the gif seems to 'hang' before restarting.

Charles Longway

Just a thought, could the loss of ice mass be sufficently high to result in isostatic rebound and increase risk of quakes?

Aaron Lewis

One gram of water vapor can melt 7.5 grams of ice resulting in 8.5 grams of runoff.

Not only is it warm, but there are warm moist winds blowing over Greenland bringing latent heat from other areas. Melt on Greenland is no longer limited to just local insolation.

In the past those winds were cooled and the latent heat condensed out by snow cover and sea ice. With less sea ice and snow cover, the winds reaching the Greenland ice can be warm and moist. Now, all of the NH can supply heat for the melting of Greenland (and that final bit of sea ice.)

This is not your father's Arctic.

Ethan O'Connor

I created a version of Steve's animation with the frames registered to each other and a delay at the beginning and end:

Kris

Charles Longway asked:

could the loss of ice mass be sufficently high to result in isostatic rebound and increase risk of quakes?
.

Not so much quakes but for sure landslides.

Also, and that's a fact, in about 30 years the entire Greenland has been lifted up for about 5 cm, due to the diminishing mass that covers the island, and the latter has as a cause of course the quicj melting of the ice cap.

It fair to assume the uplifting of Greenland could trigger a quack amywhere else in the world - tectonic plates are somewhat bounded to each other after all.

But we have no means at all to investigate nor detect if that would be the case or not.

Steve Bloom

"It fair to assume the uplifting of Greenland could trigger a quack amywhere else in the world - tectonic plates are somewhat bounded to each other after all."

Doubtful. Great earthquakes don't seem to have any such effect even though they are far more energetic than a little isostatic rebound. More local effects of rebound on tectonic activity are a different matter entirely.

Peter Ellis

"It fair to assume the uplifting of Greenland could trigger a quack"

Why, will it wake the eider ducks?

Neven

Nice animation!

Al Rodger

SteveMDFP,

That is one startling animation.

You describe your animation as covering "the last 10 days" and I wondered if those days had dates so we could relate the images to the graphs at Jason Box's Meltfactor.
The graphs presently show to something like July 4th. The really dramatic part of the graphs are perhaps mid-June and this may be the date of "the last 10 days" images available.

SteveMDFP

Al,
Right...it's from the ASCAT images, you get to them from Neven's "daily graphs" page. Then "Radar images of the entire Arctic from the EUMETSAT METOP satellite." From here, you scroll down to the Northern Hemisphere images. The ten images in the animation start with "msfa-NHe-a-2012186.sir.gif" So, by label, days 186 - 195. Date stamps are July 6 - July 15. One more image has been added since I put this together last night--no major change from the final frame.

It's a massive, sudden landmass-wide change in the radar images. Not much to see on the optical MODIS pictures, though. Figuring out exactly what we're looking at is the interesting task.

Until now, every radar image of Greenland I've seen has shown this dramatic bright ring around the entire landmass. The southern rim of this has shifted northward some over time, but otherwise seems quite stable, until now.

To my mind, we have to be looking at a dam of ice just under the snowcover that circles the landmass--what else could be more reflective than bare rock? It's probably only so bright when the top surface is flat horizontal, perpendicular to the radar signal. It then disappears from the image not because it's all suddenly dissolved, but because the top surface of this ice is no longer smooth, flat, and perfectly horizontal.

Slush and meltwater must have built up just inside of this vast circular dam. With warm temps and increased melt, the ice dam gave way in the south, and then the shockwave either travelled clockwise around the whole circle, or maybe shockwaves travelling through the ice mass caused collapse all the way around.

If I'm right about this, folks on Summit Camp should have heard or felt something dramatic, even though they're far away from the presumed ice dam. It would have been about the 12th, I think, that it would have been most noticeable.

Given the extent and speed, I'd think seismographs in Canada and maybe Iceland would have picked up something.

The initial break in the south was relatively far from the coastline, so actual release of meltwater at the coast should have been almost simultaneous all around the whole coast of Greenland.

Like I said, when I put the animation together and watched, I was totally floored. And to think that there's so little to see on the optical images. Amazing.

Al Rodger

SteveMDFP,

Date-wise, your day 186-195 animation would be from July 4th-13th for a leap year. So the 'event' we witness post-dates Jason Box's latest Meltfactor graph updates.

Having viewed the images as per the Daily Graphs link, it is certainly an event that didn't happen in 2011 or 2010.
Being radar, it is longer wavelength than IR so whatever the phenomenon doing this, it may not impact on albedo so may not appear on the Meltfactor graphs.

Two things strike me. Firstly the shape within the ring of white has remained intact for over 2 years but the suddenly is gone in a couple of days.
Secondly, the white area is not apparent that much elsewhere. Only Svalbard, FranzJoseph Land, the North end of Ellesmere struck me as showing white like that ring on Greenland which extends in size over Autumn & shrinks to a ring in Summer (until this July).

I do wonder if the white is something like the radar signature of a well-sloped frozen icefield. Perhaps the white is the radar amplifying off the lips of the frozen melt from last season as it steps down from the summit. And then, what we are witnessing is the melt reaching the actual summit of Greenland's Ice Sheet & the last of those frozen lips of ice going watery & darkening.
This is of course is entirely idle speculation from a small brained mammal.

Espen Olsen

Urgent: Please read : Arcticicelost80 on ASI 2012 update 7: steady as she goes

Al Rodger

What was it I said above "Being radar, it is longer wavelength than IR so whatever the phenomenon doing this, it may not impact on albedo so may not appear on the Meltfactor graphs.

Well it did appear.

http://www.meltfactor.org/blog/?p=514

Neven

It looks like Dr. Box might have to adjust the Y-axis on his 2000-2500m graph...

The weather forecasts have a high stuck over Greenland for at least the next week.

Neven

In the meantime from Sermitsiaq (via Google Translate):

New heat record in Greenland

In Qasigiannguit Asiaq has measured 23.3 degrees - that's a record for the area in Disko Bay.

Last week, Kangerlussuaq was hit by huge masses of water from the ice cap, and yesterday it emerged that an area that is more than twice as large as Manhattan, has broken off Petermann Glacier in northwestern Greenland.

Now, says Asiaq that recently measured 23.3 degrees Qasigiannguit in Disko Bay.

This is the highest temperature that Asiaq have measured during the 21 years that the company has carried out measurements in Qasigiannguit, as confirmed by Per Hangaard, climate employee of Asiaq.
Record temperatures were measured on 10 July.

SteveMDFP

Al Rodger, et al

The further drop in albedo in Greenland is definitely worrisome. It does coincide in time fairly closely to the drmatic drop in "Radar albedo" that my animation shows. But I'm inclined to think that they are very different processes, but both related to melt of snow and ice.

I'd chalk up the optical albedo increase probably mostly to soot from the fires in Siberia. The've been massive, with astounding amounts of smoke visible in the top-right photo in the arctic mosaic (r06c06) for essentially a whole month. Winds have consistently carried this northward (and eastward). The smoke has altered ozone levels as far as British Columbia.

The radar "albedo" increase, I suspect, cannot be explained by soot on Greenland -- too sudden, and sooty material previously prominent on the ice sheet doesn't seem to show on radar--though the resolution of the radar images is too poor to make this statement with confidence.

Meanwhile, the bright radar line seems to be reorganizing in Greenland, farther inland. I have to think that this represents a border between freezing and melting of melt and runoff.

Janne Tuukkanen

I don't think one years soot could cause visible albedo decrease. If, however, the snow is melting, dust particles from many years will concentrate on the surface. And all that dog poop from explorers' huskies too :)

Melting snow is also wet snow, and the scatterometer radar would react that. The white band around central plateau could be caused by dip angle, which could alter the radar signal.

So, the radar would correlate with surface albedo as long as that correlates with the wetness of snow. If snow is dry, but still disappearing (as in some parts of Antarctica, where snow and ice sublimate directly to air), there would be no correlation.

My 0.02 euros.

Account Deleted

http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2156

"The coldest place in Greenland, and often the entire Northern Hemisphere, is commonly the Summit Station. Located at the top of the Greenland Ice Sheet, 10,552 feet (3207 meters) above sea level, and 415 miles (670 km) north of the Arctic Circle, Summit rarely sees temperatures that rise above the freezing mark. In the 12-year span 2000 - 2011, Summit temperatures rose above freezing only four times, according to weather records researcher Maximiliano Herrera. But remarkably, over the past week, temperatures at Summit have eclipsed the freezing mark on five days, including four days in a row from July 11 - 14. There are actually three weather stations located at the location--Summit, Summit-US, and Summit AWS. The highest reliable temperature measured at any of the three stations is now the 3.6°C (38.5°F) measured on Monday, July 16, 2012 at Summit-US. A 4.4°C reading at Summit in May, 2010 is bogus, as can be seen by looking at the adjacent station. Similarly, a 3.3°C reading from June 2004 is also bad. Records at Summit began in 1996."

Andrew Borst

Is that the first time Dr. Masters linked to this site, Neven? Good to see you recognized, I think this is one of the most interesting sites on the internet.

Neven

Thanks, Andrew. Could be the second time, I'm not sure. But never so directly. We're on the right track.

idunno

I see that DMI has started adding local Surface Sea Temperatures anomalies to some of its local satellite image maps:

http://ocean.dmi.dk/arctic/disko.uk.php

With the main DMI SST map showing anomalies of 4Centigrade for almost all of Baffin Bay, I think it very likely that the whole of the West Coast of Greenland will continue to bask in the current heatwave for months to come.

From my limited meteorological lore, I presume that the air over the warmer water will warm, and absorb more evaporated water. It should then tend to head East, due to the jet stream and the Coriolis effect. As it hits the edge of the ice sheet, it cools, gains altitude and so this causes precipitation.

By October, most of this extra precipitation may be snow. But in the mean time, I predict a lot of melt.

Kangerlussuaq was reporting 21C today; as were several other Western Greenland stations.

Seke Rob

A little diversion... temps of RSS and UAH where I've just added 11 more months through June 2011 (UAH-MSU by the chieftains, Christy/Spencer who claim fervently that their own data does not indicate warming): http://bit.ly/UAHRSS No warming since 1997, or was it 1998, or popular too, 2001. It sure heck looks like it's not cooling either, and that Spanish boy is growing up, again.

On ice, JAXA did not record a century, but YTD has almost fallen through the 2003-2011 anomaly basely: http://bit.ly/JAXEXA . No CT data update yet. Day before the deviation from normal ran at -2.95. http://bit.ly/CTAR02 with a 365 days rolling anomaly of -1,139 million, still very close to 2 standard deviation, off from the full instrumental data period.

idunno

Meanwhile, over at meltafctor, Dr Box needs to invest in a new y-axis:

http://www.meltfactor.org/blog/?p=514

Steve Bloom

And now what look to be frequent updates at Climate Progress as well, which makes for two influential, high-traffic sites. At this rate, that pseudonym may be the only thing standing between Neven and fame. :)

Rob Dekker

idunno, thanks for Dr. Box's update on the albedo changes in Greenland.
These most recent numbers (for the albedo anomaly) look a lot worse than what Neven presented just a few weeks ago in the "dark side of Greenland" post.

So, let me re-do my "back of the envelope" calculation :

We know that Greenland receives some 250 - 300 W/m^2 insolation 'on the ice' during June/July.
With a change in albedo of 3 % to (as Dr. Box's recent numbers show) to 6 %, how much ice will melt over the entire ice sheet due to this change in albedo alone ?

If we do the simple physics calculations of increased solar absorption of 3-6% albedo change, we get to a ice loss anomaly of some 7 - 14 cm or, over the entire 1.7 million km^2 ice sheet.
Over the entire 1.7 million km^2 ice sheet, this would imply an additional loss of 120 - 240 Gton per month (that the surface temps remain close to freezing on Greenland) due to this albedo anomaly alone.

In comparison, total annual ice poduction of Jakobshavn Isbræ is some 35 Gton, even after it doubled in speed a few years ago.

Please tell me that these calculations are not right, because if they are, we should be very concerned...

Werther


Photobucket

Morning Espen (see the Petermann thread),
Yesterday’s r03c03 gave a better view of the Fade Isblink and its surroundings. The melt/break-up is much more intense than 2010-11 day 201. No wonder, the automatic weather stations on Cape Morris Jessup and Station Nord came up with +11-12 dC yesterday.
On the other side of the Isblink, Henrik Kroeier Holme reported just above zero.
That region has, through its geomorphology, diverging climate/weather aspects. Interesting.
IMO this illustrates the rapid change all around Greenland this year. SST’s are extremely high, in the west up to Kane Basin, in the east all along the sea ice tongue into Fram Strait.
The ‘Dr.Francis’-ridge has been stable over Greenland for weeks. Within it, a lot of warmth is exported to the Arctic. It shows on the 500 Mb reanalysis (see above; 1jun-12jul).
It is weather, but enhanced through AGW.

Werther

Sorry, that was SLP, here's 500 Mb:
Photobucket

Rob Dekker

Werther,
Quick question for you. I noticed you are using photobucket for your icons and pictures. Does that service also support avi (movie) files, and in general would you recommend it ? Reason I asked is that I am capturing the OBuoy4 & 6 images, and have made them into (avi) movie files, that I would like to share with you guys.

Werther

Hi Rob,
That sounds too advanced for me. Last time I tried to incorporate a YT video (Watson River), Typepad nearly blocked me out for several days. Ask Neven?

Werther

OTOH, Rob,

Why not enter the link; we could watch it through Windows Media layer?

Neven

Ask Neven?

Rob, you can send those vids to me and I'll put a blog post up.

Neven

And now what look to be frequent updates at Climate Progress as well, which makes for two influential, high-traffic sites. At this rate, that pseudonym may be the only thing standing between Neven and fame. :)

I'm ready for the paparazzi! Justin Bieber, eat your heart out! :-P

Werther

Greenland…
Over the Arctic, each period since 2007 could have been defined by some sort of anomalous, synoptic scale feature. FI the ‘Kara Bulge’ last autumn. This summer, it is the large anomaly over Greenland, visible on 500 Mb pressure, 400/850 Mb temperature and 500 Mb vector wind anomalies.
High SLP is common over Greenland. This summer, it is not especially different on the 1000 Mb level. But it is higher up in the troposphere. The 500 Mb level is way up compared to normal. It is accompanied by high temps on 850 and 400 Mb. So the series of record high temps measured in Summit is embedded in these NCEP/NCAR reanalyses.
Winds around this feature are anomalous (southerly) over the Baffin Bay (see also Kimmirut temps FI) and the contrary in the Iceland region. It is tentative to relate that to the high SST’s in these regions (warmer subsurface layers being mixed in).
Another aspect of the feature is anomalous low Outgoing Longwave Radiation over south Greenland.
Descending air masses in high pressure tend to get dry. A lot of sunshine is able to pass. The OLR shows a lot of that is absorbed (much more than during the same period '07 or '11).
That sort of describes the background of the recent events on Greenland.
Leaves the question: Why? Chris Reynolds has related the Francis study on slow, meandering jetstream and Rossby Waves to the constant drenching of the British Isles. Jeff Masters did so (I think) to the Mid West drought in the USA.
The Greenland Ice sheet is a formidable, 2600 km long barrier into the troposphere up to the 400 Mb level. It is tentative to imagine the Rossby Wave pattern almost stuck on that ridge.
This is something new. It didn’t pass that consistent and long in the past. Models won't capture this sort of anomaly, although they do refer to the possibility.


Werther

Oh yeah... that about wraps it up on the issue of soot, related to recent events on Greenland. It is not the major driver, but a contributor.

Al Rodger

Rob Dekker
Taking your "on-the-ice" insolation figures as given, your numbers check out. I did wonder about how much energy would be used heating the ice to melting point. I read the ice is mainly at some -30 deg C so I make that 20% of the energy has to be subtracted to heat the ice up to maintain temperature gradients.
According to GRACE, Greenland is losing about 400Gt per year at present, that's up 300Gt or so on the decade. It also has something like 600Gt to shed because of annual rain/snowfall. So assuming no large increases in precipitation, GRACE will soon show if there is an increase in mass loss of 200-400Gt on the year and whether your (& my) arithmatic stacks up.

Twemoran

Werther
In the Flade Isblink area - both the north and the south are shedding FYI and I believe some MYI.

The fast ice to the south almost dislodged last year, and I believe someone postulated that if might be grounded on a bar in the center of the gyre that contributes to the NOW polynia. R02c03 today is showing wide cracks.

Terry
BTW

Will harbor facilities be required soon at Nord?

Twemoran

Woops - meant the NEW Polynia of course.

Terry

Mdoliner43

Can anyone explain why the Greenland Ice Sheet albedo went up from June to July?

Twemoran

Mdoliner

Possibly late June snow above 2,000M?

Terry

Werther

Photobucket
Maybe we could break up events in periods; here's 12-17 july.

Werther

Photobucket
And this period fits well with the upward period of albedo...

Werther

Sorry for the format changes...
Digesting the reanalysis data, I see a strong relation between mid-tropospheric temps/thaw on 1500-2500m/albedo change.
It is very interesting to see temps rising dramatically between 7 and 12 july. At the end of that period some large melt lakes above Sermeq Kajullac emptied. Two days later the bridge at Kangerlussuaq 'collapsed'.

Rob Dekker

Al Rogers, thanks for double-checking my calculations.
I think the key point is that real melt due to albedo change does not occur until temperatures (at any altitude) are close to freezing. When it's -30 C, it does not matter what the insolation it. We see the same thing for Arctic sea ice melting : Early in the season, temps are below freezing, and albedo stays high deep into June (with brutal insolation). It's only when atmospheric temperatures approach freezing when the first snow melts. Then albedo changes, which increases radiative absorption, which causes melt to really kick off. This is a 'positive' feedback (actually one with a threshold), which operates in Greenland as well. The scary thing is that there is not much of limiting factor to this effect : June is still late for melting to commence, and it can easily go back into May or even April, without much "pushback" to this positive feedback.

Incidentally, I posted my calculations to Dr. Box'es site as well, and he confirmed them too, with a link to his paper.
http://www.meltfactor.org/blog/?p=514&cpage=1#comment-3217

Subsequently I made the following post there, which kind of sums up my real concerns about the Greenland ice sheet. I think it may get a lot wetter in Greenland in the July's of the future, and this is why :

-----

Dr. Box, thank you for your response, and the link to your paper.
The conclusions of that paper are concerning, especially since you identified a spectrum of positive feedback mechanisms, which would take any simple linear increase in atmospheric warming around Greenland into a quadratic or even polynomial increase in Greenland ice sheet melting. After all, an increase in surface warming not only extends the melt period at any altitude, but also increases the altidude where any melt occurs. That is already a quadratic positive feedback during the melting season, not even counting the drop in albedo that melting creates, which sort of self-amplifies melt due to increased solar irradiance absoption.

In the abstract of your paper, you write :

Abnormally strong anticyclonic circulation, associated with a persistent summer North Atlantic Oscillation extreme since 2007 enabled three amplifying mechanisms to maximize the albedo feedback: (1) increased warm (south) air advection along the western ice sheet increased surface sensible heating that in turn enhanced snow grain metamorphic rates, further reducing albedo; (2) increased surface downward shortwave flux, leading to more surface heating and further albedo reduction; and (3) reduced snowfall rates sustained low albedo, maximizing surface solar heating, progressively lowering albedo over multiple years. The summer net infrared and solar radiation for the high elevation accumulation area approached positive values during this period. Thus, it is reasonable to expect 100% melt area over the ice sheet within another similar decade of warming.

Allow me to make a few notes on this statement. For starters, the NAO seems not to be very extreme since 2007.
http://climatedataguide.ucar.edu/guidance/hurrell-north-atlantic-oscillation-nao-index-station-based
suggests that over the past decade, there is nothing unusual about the NAO. Some years are positive, some are negative. No
real extremes though.

If not from NOA, could it be that the 'trigger' of "increased warm (south) air advection" is simply increased global average temperatures at lower latitudes, which are amplified by a significant decrease in albedo due to record breaking snow cover anomalies in May/June over the last decade ?
http://nsidc.org/arcticseaicenews/files/2012/07/Figure5a.png
http://nsidc.org/arcticseaicenews/files/2012/07/Figure5b.png
After all, a 6 million km^2 in June snow anomaly does seem to bring an addition 1000 TW into the melting season, if we follow the same simply physics calculations.
Or is that hypothesis too far fetched ?

Given the 2 polynomial orders positive feedback (increased surface warming extending melt period, as well as increasing altitude where melt occurs) plus the feedback that melt causes a decrease in albedo, which self-amplifies warming while insolation is high (June, July) plus the snow cover anomaly at lower latitudes early in the melting season, seems to suggest that there is up to a 4th order polynomial positive feedback into the system that leads to Greenland ice melt.

That can't be good, going into the 21st century with increased AGW, right ?

Kevin McKinney

Rob, I realize it's Dr. Box's words, but can you explain:

"(2) increased surface downward shortwave flux, leading to more surface heating and further albedo reduction..."

How is this flux a feedback? I'd have thought this was straight insolation, which is a forcing.

Presumably, the loop runs via clearer skies resulting from the 'anti-cyclonic' circulation, but this would seem to imply that the albedo changes are affecting/driving the circulation changes. Otherwise the loop doesn't close. Is that what he's saying (perhaps elsewhere in the article), or is that elsewhere in the literature?

Or am I simply confused?

Werther

Kevin,
In a way that flux increase is a feedback. The images I posted above illustrate my view that anomalous high surface level pressure combined with extreme geopotential height on 500/600 Mb shaped up a perfect sky for the sun’s radiation to pass. The most extreme phase was 7-17 july.
Things have become less relentless on the GIS as the bulge crossed into the Canadian Archipelago. There’s a solid freeze again at Summit.
I wonder what the sky would have looked like over Summit during the extreme lucidity. Must have been heavenly blue…

Kevin McKinney

"...anomalous high surface level pressure combined with extreme geopotential height on 500/600 Mb shaped up a perfect sky for the sun’s radiation to pass."

Thanks, Werther. That's essentially the clearer skies I mentioned, fleshed out with salient detail. But if I'm conceptualizing this right, for a feedback loop to exist this increased insolation would then have to 'make its own weather' to some extent, correct?

(As I understand it, that's what we see happening with the current Midwest drought in the USA--soil drying increases surface temperatures, which inhibits precipitation, which increases soil drying.)

So do we think an analogous process happened over GIS? The warming, such as was seen over Summit, then affects circulation in such a way as to prolong the 'clear spell?'

Werther

Guess you're right on that, Kevin. Have to think that 'make it's own weather'-thing over.
The extreme sit over the GIS didn't enforce itself. It comes and goes with the Rossby-waves. BTW, there was a constant 500 Mb ridge into the midwest all the time may-july.But although there are process-similarities, the morphology is so very different...

Kevin McKinney

"But although there are process-similarities, the morphology is so very different..."

Yes, that's putting it mildly!

Werther

Zachariae day 204
Large pieces of the fast ice containment in front of the glacier are breaking up.
A quarter of the ice on the north side, right before the calving front is opening, as it did last year around day 220.
On the feeding sheet large melt lakes have appeared, rivers are running down. The melt zone is generally 50 km deep and the equilibrium line seems to be around 900-1000m aSL. This is twice what it was last year.
I wonder if, this far north (79N), the Zachariae is preparing a surprise…

Daniel Bailey
" I wonder if, this far north (79N), the Zachariae is preparing a surprise…"
Just wakening from a long slumber. As are the other outlet glaciers of Northern Greenland.
"Area losses at the fronts of glaciers can translate to less flow resistance and in turn accelerated flow. More than 3/4 of the area losses are at north Greenland glaciers that I see as awakening sleeping giants. The Humboldt, Petermann, and 79/Zachariae glaciers have bedrock troughs that lead inland below sea level. Other than another ice age, there is no expected mechanism to prevent retreat from continuing into the heart of the ice sheet, hastening it's demise."
Rob Dekker

Kevin McKinney said

Rob, I realize it's Dr. Box's words, but can you explain:

"(2) increased surface downward shortwave flux, leading to more surface heating and further albedo reduction..."

You are right that remark does not sound obvious. Still, Dr.Box mentions this about that shortwave flux increase:

Positive anomaly-gauged feedback concentrated in the ablation area accounts for more than half of the overall increase in melting when satellite derived melt duration is used to define the timing when net shortwave flux is sunk into melting.

Thus, it seems that he means that because the "duration" of melt will increase, therefore there is increased shortwave influx which contibutes to melting. That is kind of a different way of saying that increased temps cause an increase in 'duration' of melting, and thus this is a positive feedback. (One of the four that I mentioned).

crandles

>"(2) increased surface downward shortwave flux, leading to more surface heating and further albedo reduction..."

>How is this flux a feedback?

Surely it doesn't say it is a feedback merely an "amplifying mechanisms to maximize the albedo feedback"

So the amplifying mechanism is the 'increased surface downward shortwave flux' which warms the surface and reduces albedo

Then the feedback is albedo decrease means more insolation absorbed resulting in more melting and more albedo decrease and so on.

crandles

It seems to me all three factors are giving albedo feedback an early kickstart so duration of melt does increase.

The longer duration of melt (earlier start) is an effect of these three amplifying mechanism. But is the longer duration a feedback? Do warmer temps mean less autumn snowfall sticks meaning earlier start to albedo feedback the next year?

Janne Tuukkanen

Interesting seminary lecture about airborne radar measurements of ice and snow:

http://www.podcast.tv/video-episodes/jones-seminar-radar-sounding-and-imaging-of-glacial-and-sea-ice-status-and-future-17475810.html

A few not so enthusiastic words about satellite measurements in the end.

a_yeeles

Janne
We native English speakers really, really appreciate the efforts on this blog of those who aren't (especially when a small misunderstanding raises a smile ;)

Presumably you meant to say "seminal", which means highly original, influential, and important. "Seminary" is a school for priests.

But, who knows, perhaps airborne radar is a hot topic at the Vatican nowadays!

Artful Dodger

An ice tithe? An alternative to a carbon tax?

Werther

http://www.meltfactor.org/blog/?p=556
New entry by Dr. Jason Box on his blog.

Kris

Werther wrote:

Jason Box on his blog
.
Do I interprete it right: "on 18 july 2012 microwaves penetrated to the soil, to the bottom of the ice sheet for almost the entire southern part of Greenland"?

AmbiValent

I thought it just meant absorption by a non-ice layer, probably consisting of dirt and soot, meaning all the ice that had been above that layer had melted. Below that absorption layer would be a lot more ice - although the absorbed heat would start to melt it.

FrankD

Hang on, what's this about scientists firing microwaves into the Greenland Ice Sheet? That's how I defrost my dinner! No wonder the damn place is melting! I'd say EUMETSAT have some explaining to do.

(Sorry, I think I need a new tinfoil hat...)

Apocalypse4Real

A new NASA article on unprecedented July 2012 Greenland ice melt.

http://science.nasa.gov/science-news/science-at-nasa/2012/24jul_greenland/


Artful Dodger

Hi Neven,

You may wish to update this post with a video taken on July 21, 2012 flying by helicopter over the damaged bridge over the Watson River at Kangerlussuaq, Greenland:

http://www.youtube.com/watch?v=kKjXKAatiIs

Cheers,
Lodger

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