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A-Team

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Re: Greenland 2016 Melt Season
« Reply #50 on: April 18, 2016, 01:43:55 PM »
I'm struggling to see this. West Greenland was supposed to melting too, all the way north of Jakobshavn to Store Gletscher.
« Last Edit: April 18, 2016, 02:01:15 PM by A-Team »

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Re: Greenland 2016 Melt Season
« Reply #51 on: April 18, 2016, 02:47:51 PM »
The forecast still looks like Greenland may be in for another heat wave:
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Re: Greenland 2016 Melt Season
« Reply #52 on: April 19, 2016, 01:27:58 PM »
Quote
The forecast still looks like Greenland may be in for another heat wave:

However this new one plays out, I'm beginning to wonder overall if current climate models have any kind of grip on future weather patterns coming to Greenland.

Where in published climate models do we find the odd weather seen these days? If it is not some one-off random weather noise but a harbinger of an unforeseen new normal, we're in trouble a lot sooner than expected. It's fair to say that nobody has a clue which it is.

Rain rather than snow, thin clouds that hold in the heat as in the 2012 extreme, more open water longer in the adjacent Arctic Ocean, meltwater induced changes in the AMOC off SE Greenland -- these strike me both individually and jointly as inherently unfavorable for accurate modeling at a fine enough scale to predict the the necessary subtleties of localized temperature and precip trends that matter to the western Greenland ice sheet.

Along these same lines, I'm becoming increasing skeptical that paleo (ie the last interglacial) has any applicability to the near-future of Greenland. Although the ice sheet overall got through the Eemian better than once thought, a long list of considerations such as warming ramp-up and Milankovitch phasing do not seem remotely comparable. I would say the same -- little guidance there -- even had the ice sheet completely melted out back then.

The risk with both paleo and climate models is false reassurances followed by complacency. To justify their existence, academic fields must exude confidence and continually overstate knowledge and applicability. This does not seem to be working out for us if recent developments are any indication. Yet wait-and-see does not provide much lead time compared to precautionary principle.

RaenorShine

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Re: Greenland 2016 Melt Season
« Reply #53 on: April 19, 2016, 01:36:37 PM »
NSIDC have now started the daily melt readings, and have updated the graph back to the beginning of the year. it shows the early melt blast at around 10% of the area, similar to the DMI model.

Image courtesy of the National Snow and Ice Data Center, University of Colorado, Boulder.

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Re: Greenland 2016 Melt Season
« Reply #54 on: April 19, 2016, 01:37:29 PM »
Full disclosure:  I'm not a scientist....but a financial guy.

Quote
Along these same lines, I'm becoming increasing skeptical that paleo (ie the last interglacial) has any applicability to the near-future of Greenland.

I've dealt with models in the financial world....and they "work" when conditions closely approximate what happened before under the same circumstances.

I have felt like you for a few years.  We are NOT dealing with the "same circumstances" AT ALL.  The rise in CO2 seems to be leading to a very fast transition to a new climate......where feedback forces are on steroids.  And we aren't even to the point of "finishing off" the Arctic ice sheet yet.  When that puppy is gone....Greenland is TOAST.  And just getting to that point.....with more and more open water is really putting the hammer down on the Arctic ice AND the Greenland ice sheet.

But to your point....I think the climate models are VERY LIKELY UNDERSTATING what is NOW happening...and will happen in the next 5 - 10 years as you know what hits the fan.

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Re: Greenland 2016 Melt Season
« Reply #55 on: April 19, 2016, 06:39:36 PM »
Full disclosure:  I'm not a scientist....but a financial guy.

Quote
Along these same lines, I'm becoming increasing skeptical that paleo (ie the last interglacial) has any applicability to the near-future of Greenland.

I've dealt with models in the financial world....and they "work" when conditions closely approximate what happened before under the same circumstances.

I have felt like you for a few years.  We are NOT dealing with the "same circumstances" AT ALL.  The rise in CO2 seems to be leading to a very fast transition to a new climate......where feedback forces are on steroids.  And we aren't even to the point of "finishing off" the Arctic ice sheet yet.  When that puppy is gone....Greenland is TOAST.  And just getting to that point.....with more and more open water is really putting the hammer down on the Arctic ice AND the Greenland ice sheet.

But to your point....I think the climate models are VERY LIKELY UNDERSTATING what is NOW happening...and will happen in the next 5 - 10 years as you know what hits the fan.

The link leads to a NOAA presentation at a January 29 2016 seminar on climate models, and the attached image shows how well various CMIP5 models match the indicated observed data.  In an ideal world all of the squares on the matrix would be colored deep blue; which gives an idea just how fare current climate models have to go to reasonably match reality.

http://cpo.noaa.gov/sites/cpo/MAPP/Webinars/2016/01-29-16/Lamarque.pdf
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Re: Greenland 2016 Melt Season
« Reply #56 on: April 20, 2016, 02:33:33 PM »
I think a large part of the problem is that the very concept of climate implies a certain level of stability.  We are currently in a situation where the planetary energy levels are in a state of change.  If you run a model 100 times in a changing system you are going to find 100 different results.  It is highly unlikely to be able to predict how all of this new energy is going to effect a million different variables.  In a complex system in a state of flux chaos rules, in my limited understanding, this is where the butterfly effect is important, this is where the diversity of possible futures is highest.

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Re: Greenland 2016 Melt Season
« Reply #57 on: April 20, 2016, 06:21:02 PM »
I think a large part of the problem is that the very concept of climate implies a certain level of stability.  We are currently in a situation where the planetary energy levels are in a state of change.  If you run a model 100 times in a changing system you are going to find 100 different results.  It is highly unlikely to be able to predict how all of this new energy is going to effect a million different variables.  In a complex system in a state of flux chaos rules, in my limited understanding, this is where the butterfly effect is important, this is where the diversity of possible futures is highest.

Conventional wisdom is that weather is chaotic but climate is not being a boundary condition problem rather than a chaotic problem.

"In a complex system in a state of flux chaos rules" If there is a stable underlying system with chaotic noise on top, how are you ruling out small stable changes in the underlying system in order to jump to the chaos conclusion?



All models are wrong; some models are useful.
In this case, models are better at some things than others. Probably important to try to use them where they are reasonable? If you want to use them where they are bad, maybe a few bad models is better than no model, but take care.

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Re: Greenland 2016 Melt Season
« Reply #58 on: April 21, 2016, 05:27:52 PM »
The ratio of the NOAA Temp Anoms for the Land vs Land-Ocean is much higher for the 2015-16 Super El Nino event than for the 1997-98 Super El Nino event (see the data at the following links):

http://www.ncdc.noaa.gov/cag/time-series/global/globe/land/p12/12/1880-2016.csv
http://www.ncdc.noaa.gov/cag/time-series/global/globe/land_ocean/p12/12/1880-2016.csv

I suspect that this is partially the case because in 2016 the cold spots in the North Atlantic, and the Southern, Oceans are much more pronounced than in 1998, which reduces the Land-Ocean Temp Anom while leaving the Land Temp Anom largely unaffected (see the attached image from the linked NOAA State of the Climate report for March 2016):

https://www.ncdc.noaa.gov/sotc/global/201603

I would like to know if anyone here has the skills to analyze the amount that the North Atlantic, and Southern, Oceans cold sports (associated with glacial ice melting) are suppressing the global mean land-ocean surface temperature anom, by integrating the color coding of the cold spots shown in the attached NOAA temp anom map (note that per Hansen et al 2016 the magnitude of this suppression will likely increase rapidly if we stay on the RCP 8.5 90%CL pathway that we are currently following).
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Re: Greenland 2016 Melt Season
« Reply #59 on: April 21, 2016, 10:24:41 PM »
Quote
skills to analyze the amount that the North Atlantic, and Southern, Oceans cold spots (associated with glacial ice melting) are suppressing the global mean land-ocean surface temperature anom, by integrating the color coding of the cold spots

It would be a nightmare as the pixel count for each color would have to be convoluted with the areal distortion of each each lat/lon square in their long-depracated Robinson projection. The coloration is all wrong -- the palette squares themselves are a mixed bag of thousands of colors. That can't be fixed here by posterizing to say 5-bit. Although it is a small .png file, it has undergone lossy compression. The land boundaries and grid should always be done as a removable layer.

More importantly, it was the authors' job to provide the color histogram numbers in the first place, indeed to do the analysis you are proposing. Plus place a prominent link to an archived numerical table. So another piece of throw-away eye candy?

If you want science-level graphics, you may have to restrict your reading to papers from the E Rignot group and handful of others.

Quote
The Robinson projection is neither equal-area nor conformal, abandoning both for a compromise. The creator felt this produced a better overall view than could be achieved by adhering to either. The meridians curve gently, avoiding extremes, but thereby stretch the poles into long lines instead of leaving them as points. Hence, distortion close to the poles is severe, but quickly declines to moderate levels moving away from them.  https://en.wikipedia.org/wiki/Robinson_projection
« Last Edit: April 21, 2016, 10:51:04 PM by A-Team »

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Re: Greenland 2016 Melt Season
« Reply #60 on: April 21, 2016, 10:46:42 PM »
So another piece of throw-away eye candy?

If you want science-level graphics, you may have to restrict your reading to papers from the E Rignot group.

Thanks for the thoughtful reply.  Who knows, maybe Rahmstorf will write a new peer-reviewed paper on this topic.  However, Rahmstorf might need to expand his interest in cold spots to include the Southern Ocean.



See also:
https://climatecrocks.com/2016/03/01/mystery-deepens-around-greenland-cold-spot/

Extract: "The North Atlantic between Newfoundland and Ireland is practically the only region of the world that has defied global warming and even cooled. Last winter there even was the coldest on record – while globally it was the hottest on record. Our recent study (Rahmstorf et al. 2015) attributes this to a weakening of the Gulf Stream System, which is apparently unique in the last thousand years.

The whole world is warming. The whole world? No! A region in the subpolar Atlantic has cooled over the past century – unique in the world for an area with reasonable data coverage (Fig. 1). So what’s so special about this region between Newfoundland and Ireland?"
« Last Edit: April 21, 2016, 10:52:56 PM by AbruptSLR »
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Re: Greenland 2016 Melt Season
« Reply #61 on: April 23, 2016, 10:44:23 AM »
The forecast is pretty epic by May 1st gis will be snow free on land South of 70S.

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Re: Greenland 2016 Melt Season
« Reply #62 on: April 24, 2016, 09:19:22 PM »
With the recent heatwave on Greenland and another one coming aorund next few days (0-isotherm lingering around and above 1500m in many places in the south for many days), I would have liked to follow some runoff numbers. Like we have in Norway:

http://www2.nve.no/h/hd/plotreal/Q/index.html

especially this one which drain directly from the glacier Jostedalsbreen, and spikes in mid-summer heat-waves:

http://www2.nve.no/h/hd/plotreal/Q/0078.00008.000/

Anyone know of something??

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Re: Greenland 2016 Melt Season
« Reply #63 on: April 25, 2016, 01:56:47 AM »
Quote
like to follow some runoff numbers for s Greenland. Like we have in Norway: Anyone know of something?
very impressive array of gauges there in Nway.

For western Greenland, the marine terminating glaciers don't have surface rivers so much; water exiting the glacier at the base of the calving front say 500 m below sea level, is only rarely measured by sonar.

Land-terminating glaciers to the south of Jakobshavn may have gauges seasonally. However with braided, shifting outlet streams it would not be feasible to measure total outfall. Kangerlussuaq is the best bet. I believe glaciologist D van As was down there last week measuring a stream. I have not seen any real time online river web sites.

However even with river gauge, automatic weather stations and fixed GPS, we would still be thrashing around for the perfect proxy to follow to monitor how much heat was absorbed, where it went, and what effect it is having surface discharge, frozen lenses, melt lakes, crevasse wedging, moulins or bedrock lubrication in western Greenland. I think it is way too early for the latter three.

oren

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Re: Greenland 2016 Melt Season
« Reply #64 on: April 25, 2016, 03:12:26 PM »
Quote
like to follow some runoff numbers for s Greenland. Like we have in Norway: Anyone know of something?
very impressive array of gauges there in Nway.

For western Greenland, the marine terminating glaciers don't have surface rivers so much; water exiting the glacier at the base of the calving front say 500 m below sea level, is only rarely measured by sonar.

Land-terminating glaciers to the south of Jakobshavn may have gauges seasonally. However with braided, shifting outlet streams it would not be feasible to measure total outfall. Kangerlussuaq is the best bet. I believe glaciologist D van As was down there last week measuring a stream. I have not seen any real time online river web sites.

However even with river gauge, automatic weather stations and fixed GPS, we would still be thrashing around for the perfect proxy to follow to monitor how much heat was absorbed, where it went, and what effect it is having surface discharge, frozen lenses, melt lakes, crevasse wedging, moulins or bedrock lubrication in western Greenland. I think it is way too early for the latter three.

If any budgeted body is reading this, It would be great to have a chart of water flux at Kangerlussuaq (like there is for the Mackenzie for example), to be consulted during the melting season and compared between years. It should be a good proxy for southern GIS surface melt conditions. I'm not sure how difficult this might be to produce technically, given the torrential flow that comes every once in a while, and freezing conditions at other times.

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Re: Greenland 2016 Melt Season
« Reply #65 on: April 25, 2016, 04:23:48 PM »
I've dealt with models in the financial world....and they "work" when conditions closely approximate what happened before under the same circumstances.
<Philosophical Derail>There are fundamental truths in physics that are expressed as partial differential equations that may look complicated, but in their essence are really simple. Conservation of mass, energy, and angular momentum are such simple laws that are expressed as complex equations that are the basis of climate modeling.

Most people in climate debates (including many scientists) prefer to think in linear regressions between as few variables as possible. Financial models, too, have a strong foundation in past data that often is an expression of human behavior. While this has been useful, there is no guarantee that yesterday's regression is any good tommorrow.

To me as a physicist, these are not models, but statistical attempts to discern patterns where no model exists. This is why in Finance you can model only what has happened before, but in physics you can model accurately what has never happened before. The difference is that our physical laws such as conservation of mass and energy are independent of data, they always hold. This allows us to make predictions beyond the event horizon of what has happened already and for what we have no data.</Philosophical Derail>
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Re: Greenland 2016 Melt Season
« Reply #66 on: April 25, 2016, 05:03:04 PM »
can't get enough of this kind, a genuine pleasure to read ;)

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Re: Greenland 2016 Melt Season
« Reply #67 on: April 25, 2016, 06:32:33 PM »
Philosophical Derail:  Finance models vs scientific models.

Andreas:  I would agree with much that you say.  What I call "financial modeling"....is an attempt to "put numbers to what I THINK is likely to happen in the future to a number of variables."  It is based on some "laws"....but the outcome of reality in the future vs the model, is ALWAYS dependent on things we have no ABSOLUTE CONTROL OVER:  (1) The decisions people will make day-to-day, and (2) the type of "execution" people will have on a day-by-day basis, (3) as well as decisions that customers might make that affect us.

And I think what you are saying....is that is NOT "modeling to you".  I understand what you are trying to say.

In physics....the laws of physics hold.  PERIOD (for the most part...unless a "law" is found not to be true).  And you have no "difference of execution by humans" as you do in financial modeling.  So yours is a mathematical exercise of sorts...and as long as ALL THE VARIABLES have been accounted for.....it can be "modeled" out into the future that will come close to the actual outcome.

I guess I would raise two points:  (1)  if you look at the "modeling" of the Arctic ice sheet 10-15 years ago.....I doubt you would find a single model that would reflect the melt that we have to date.  Over the last 15 years.....as each year passes, the models keep brining in the date that the ice will first "be gone."  And this is really the premise for me saying that it is my belief that "the climate models" have been TOO CONSERVATIVE.  They have UNDERESTIMATED the melting of the Arctic ice sheet.

Which leads me to a second point:  (2)  If they have underestimated the melting of the Arctic ice sheet....won't that lead to them underestimating things such as (a) increased temperatures at an earlier date than modeled, (b) melting of the permafrost at an earlier date than modeled, (c) warming of the oceans at an earlier date than modeled, (d) the earlier melting of Greenland than initially modeled, etc.

The other problem with have with scientific models.....is we hand them over to politicians to make decisions with them... :-[

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Re: Greenland 2016 Melt Season
« Reply #68 on: April 25, 2016, 08:37:18 PM »
orgu, A-Team & oren

The official Greenlandic authority in charge of streamflow, river gauges and run-off is: http://www.asiaq.gl/en

As you say A-Team: no run-off measurements are apparently available online. However, you can see the current positive air temperatures up along the west coast here: http://vejr.asiaq.gl/#/table. It is also possible on the basis of these numbers and on the basis of PROMICE–data (available here: http://promice.org/CurrentWeatherMap.html ) to calculate “melting degree days” based on either daily or monthly averages (e.g.  https://www.escholar.manchester.ac.uk/api/datastream?publicationPid=uk-ac-man-scw:1b4062&datastreamId=POST-PEER-REVIEW-PUBLISHERS.PDF see fig. 2 & 4)

Norway found oil and can now afford direct measurements of almost everything in every second stream all over their country. Greenland did not find oil and can now hardly afford to keep a system of off-line data loggers running throughout the year.

I would use this opportunity to question whether we really need to know all the details of the tidewater glaciers to & fro. Do we really need to measure every freaking detail up- and down the coast to know, that harsh southerly winds along the west coast of Greenland with temperatures above freezing will lead to extensive melting and run-off. Sometimes it is sad enough to just know the overall picture of an ice-sheet vanishing before your eyes in the midst of April.

Carex

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Re: Greenland 2016 Melt Season
« Reply #69 on: April 26, 2016, 03:44:59 PM »
I think a large part of the problem is that the very concept of climate implies a certain level of stability.  We are currently in a situation where the planetary energy levels are in a state of change.  If you run a model 100 times in a changing system you are going to find 100 different results.  It is highly unlikely to be able to predict how all of this new energy is going to effect a million different variables.  In a complex system in a state of flux chaos rules, in my limited understanding, this is where the butterfly effect is important, this is where the diversity of possible futures is highest.

Conventional wisdom is that weather is chaotic but climate is not being a boundary condition problem rather than a chaotic problem.

"In a complex system in a state of flux chaos rules" If there is a stable underlying system with chaotic noise on top, how are you ruling out small stable changes in the underlying system in order to jump to the chaos conclusion?



All models are wrong; some models are useful.
In this case, models are better at some things than others. Probably important to try to use them where they are reasonable? If you want to use them where they are bad, maybe a few bad models is better than no model, but take care.

1.  Bad models are useful.  Perhaps we learn most and fastest from bad models as we learn to improve them.  I strongly believe in the use of a wide variety of models in any undertaking that involves thinking.

2. I do not consider my jump to the chaos conclusion as a given but as a higher probability.  The primary reasons being that as total energy in the system increases the likelihood that each physical feature on the planet will react to or alter the energy in the system in an unforeseen manner increases.  These unforeseen details have an increased chance of accumulating in unseen ways to produce unseen results.  Each stable underlying system is increasingly likely to be altered, to become less stable.  Although stable systems are likely to resist change, changing the systems around them increases the likelihood of changing them as well.

3. We are now in a system with energies for which we do not have solid historical data to check and calibrate our models with.  The energies in the system are continuing to increase, decreasing our ability to check the model.  The rate of increase of energy in the system is continuing to increase.  Chaos, I believe, increases the probability of un-predicted (unpredictable?) conditions occurring, particularly during the periods of most rapid change.  Once  energy levels become more stable model predictability will increase but the next steady state may not reflect the conditions that occur during the periods of rapid change.  The period of rapid change will be, at a minimum, 100 years.

4.  This is the babbling of a lowly field botanist who is better suited to roaming around the woods and looking for things.  I am happy to be schooled in matters physical and mathematical.  I consider it a complement that my comment drew criticism from you Mr. Crandles as I have had my opinions changed more than once by your commentary.

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Re: Greenland 2016 Melt Season
« Reply #70 on: April 26, 2016, 05:41:24 PM »
The first image shows the Nullschool Surface Temp & Wind Map focused on Greenland for April 26 2016; and the second shows the comparable forecast conditions for April 30 2016.  For this entire five-day period nullschool projects above freezing temperatures along large portions of Greenland's West Coast areas, which will likely stimulate calving activity for such key marine terminating glaciers in this area as Jakobshavn.
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Re: Greenland 2016 Melt Season
« Reply #71 on: May 18, 2016, 08:26:52 PM »
The Greenland melt season has continued to get off to an above average start, with a far larger melt pulse over the last couple of days.

DMI are showing that surface met has got underway in earnest on the west coast, with 2Gt being lost each day at the moment, a few weeks earlier than the 2012 start of the melt season.

Image courtesy of the National Snow and Ice Data Center, University of Colorado, Boulder.

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Re: Greenland 2016 Melt Season
« Reply #72 on: June 10, 2016, 03:05:16 AM »
Per the linked article, changes in the jet stream may well be making Greenland's melt season worse:

http://www.adn.com/arctic/2016/06/09/weird-jet-stream-behavior-could-be-making-greenlands-melting-even-worse-scientists-say/

Extract: "But when a group of scientists looked back at the last summer melt season — 2015 — they found something odd and troubling.

Specifically, they found that Greenland had shown much more unusual melting in its colder northern stretches than in the warmer south, and that this had occurred because of very strange behavior in the atmosphere above it. During the month of July, an atmospheric phenomenon called a "cutoff high" — a region of high pressure that stayed relatively immobile over the ice sheet, bringing with it sustained sunny conditions — lingered for many days and produced unusual warmth at the surface and record melting for northwest Greenland."

Edit: See also:

M. Tedesco, T. Mote, X. Fettweis, E. Hanna, J. Jeyaratnam, J. F. Booth,   R. Datta & K. Briggs (June 9, 2016), "Arctic cut-off high drives the poleward shift of a new Greenland melting record", Nature Communications 7, Article number: 11723 doi:10.1038/ncomms11723

http://www.nature.com/ncomms/2016/160609/ncomms11723/full/ncomms11723.html

Abstract: "Large-scale atmospheric circulation controls the mass and energy balance of the Greenland ice sheet through its impact on radiative budget, runoff and accumulation. Here, using reanalysis data and the outputs of a regional climate model, we show that the persistence of an exceptional atmospheric ridge, centred over the Arctic Ocean, was responsible for a poleward shift of runoff, albedo and surface temperature records over the Greenland during the summer of 2015. New records of monthly mean zonal winds at 500 hPa and of the maximum latitude of ridge peaks of the 5,700±50 m isohypse over the Arctic were associated with the formation and persistency of a cutoff high. The unprecedented (1948–2015) and sustained atmospheric conditions promoted enhanced runoff, increased the surface temperatures and decreased the albedo in northern Greenland, while inhibiting melting in the south, where new melting records were set over the past decade."
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Re: Greenland 2016 Melt Season
« Reply #73 on: June 10, 2016, 09:59:09 PM »
Greenland witnessed its highest June temperature ever recorded on Thursday
Quote
Greenland has been abnormally warm this spring. (NASA)

Nuuk, Greenland’s capital, soared to 75 degrees (24 Celsius) Thursday, marking the warmest temperature ever recorded in the Arctic country during June. Nuuk sits on Greenland’s southwest coast, where the country’s warmest weather typically occurs.

It was warmer in Nuuk than it was in New York City, where the high was only 71 degrees.

The Danish Meteorological Institute has confirmed on a preliminary basis that the Nuuk measurement would replace the previous record of 73.8 degrees (23.2 Celsius), which was set in Kangerlussuaq on June 15 in 2014. That temperature was also recorded in southwest Greenland about 200 miles (320 km) north of Nuuk.
https://www.washingtonpost.com/news/capital-weather-gang/wp/2016/06/10/greenland-witnessed-its-highest-june-temperature-ever-recorded-on-thursday/
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sidd

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Re: Greenland 2016 Melt Season
« Reply #74 on: June 11, 2016, 09:56:06 PM »
http://nsidc.org/greenland-today

Melt extent is up,up and away. I note that the saddle between north and south domes around 67N is now melting. That saddle is collapsing as in the Gregoire treatment (doi: 10.1038/nature11257), to which i have alluded earlier.

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Re: Greenland 2016 Melt Season
« Reply #75 on: June 11, 2016, 11:39:27 PM »
Could this be related to the slowdown/reverse of sea ice retreat? How much of that fresh water is making its way into the Arctic basin?
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Re: Greenland 2016 Melt Season
« Reply #76 on: June 11, 2016, 11:44:30 PM »
Could this be related to the slowdown/reverse of sea ice retreat? How much of that fresh water is making its way into the Arctic basin?

I'm thinking almost none of it enters the Arctic as currents move south on the eastern side of Greenland, and then up Baffin Bay where melt is proceeding fast, and then most of it moves south again, or God knows where.

But even if all of it would end up in the Arctic, it wouldn't have any impact at all. I can't imagine it matches what the Lena, Ob, Yenisei and MacKenzie are bringing to the Arctic.

The slowdown in the rate of sea ice decrease is mostly weather-related.
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Re: Greenland 2016 Melt Season
« Reply #77 on: June 12, 2016, 01:47:26 PM »
Isn't it more likely that the main effect of increased melt across the island is to bring more energy into the middle and base of the ice mass - thus warming the ice, reducing its tensile strength and bringing it all to a much more sensitive state even if it is still standing up pretending it is ice?

I would imagine that there  would be some 'leveling' of the temperature gradients during non-melt periods which will spread the heat throughout the ice mass - tending towards a fairly uniform temperature.  A possible end result being that vastly more ice gets brought to a temperature where it can switch from standing up and firm and moving only in terms of the ice models relating to very cold ice to a much more fluid state, under only a minor impetus.  That impetus could be thermal (more melt) and/or physical such as a minor tremor from a nearby glacier calving, a nearby earthquake or release of support as a glacier lurches down the hill. 

I'm imagine there are lots of sites with temperature probes in depth keeping an eye on this, but to me it all increases the potential for sudden surges of globally significant ice loss.

Shared Humanity

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Re: Greenland 2016 Melt Season
« Reply #78 on: June 12, 2016, 04:02:29 PM »
Isn't it more likely that the main effect of increased melt across the island is to bring more energy into the middle and base of the ice mass - thus warming the ice, reducing its tensile strength and bringing it all to a much more sensitive state even if it is still standing up pretending it is ice?

I am sure this is a major result of the melt. I believe there is another major effect where melt ponds form on the ice sheet. These areas of the ice sheet are also showing pronounced and sustained drops in elevation. None of this melt water flows on top of the ice to the sea. It instead slices to the base of the ice sheet and flows to the sea as dramatically increased basal flow, carrying with it large amounts of sediment.

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Re: Greenland 2016 Melt Season
« Reply #79 on: June 12, 2016, 05:30:03 PM »
I think we really need to look into the ice sheet under active melt pond regions to see just how mangled the basal ice is becoming?

In mining any caver collapse propagates up to ten times the height of the collapse so a swiss cheese base will loose integrity from both melt and collapse?

I fear 'slumping' over geographic structures dropping ice at higher elevations into melting zones and increasing meltwater outflow?
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Stephen

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Re: Greenland 2016 Melt Season
« Reply #80 on: June 13, 2016, 02:06:25 AM »
A few questions that maybe belong in the stupid questions thread:

Is there a chartic type graph available anywhere that allows us to compare time-of-year over multiple years?

Is there any way to estimate the volume of ice melted? (monthly perhaps?) Or do we need to wait for end-of-year for those kind of estimates?
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Re: Greenland 2016 Melt Season
« Reply #81 on: June 13, 2016, 02:26:40 AM »
GRACE is the NASA program for measuring the ice both for Greenland and Antarctica. They rarely update their official site, other than stating that 280 billion metric tons a year are melting with regard to Greenland alone, including what calves off and melts as icebergs later. Funny thing is, I watched an interview of the GRACE programs leader, who stated that the number is about 330 billion metric tons a year,again Greenland only. So, I think the site info needs updated. If anyone knows of another site that gives monthly or more frequent info, it would be great to know.

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Re: Greenland 2016 Melt Season
« Reply #82 on: June 13, 2016, 03:18:07 AM »
A few questions that maybe belong in the stupid questions thread:

Is there a chartic type graph available anywhere that allows us to compare time-of-year over multiple years?

Is there any way to estimate the volume of ice melted? (monthly perhaps?) Or do we need to wait for end-of-year for those kind of estimates?

The only graph that I now is this NSIDC graph. And maybe we have been keeping to much attention on Arctic Sea Ice and we should focus more on land and Greenland.

Big jump on June!
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
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Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

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Re: Greenland 2016 Melt Season
« Reply #83 on: June 13, 2016, 04:27:24 AM »
If that trend continues, I'm sure we will have to pay more attention.If anyone hasn't seen the clip on Youtube of Kangerlussuaq, Greenland from July 12,2012 of the bridge over Watson River washing out from melt water runoff and a tractor getting carried off, might want to look it up. This year might be worse.

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Re: Greenland 2016 Melt Season
« Reply #84 on: June 13, 2016, 04:37:50 AM »
So, I think the site info needs updated. If anyone knows of another site that gives monthly or more frequent info, it would be great to know.
Danish polar portal
(http://polarportal.dk/en/groenlands-indlandsis/nbsp/isens-overflade/)
has info such as:

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Re: Greenland 2016 Melt Season
« Reply #86 on: July 03, 2016, 02:05:41 PM »
Time.com had a short article on 7/2/2016 saying that Greenland is having an exceptional melt season. Other than stating the early start which I think everybody pretty much knew about already, they featured a GIF from NASA. Not much more info than that or any real data.
Click on image to activate


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Re: Greenland 2016 Melt Season
« Reply #87 on: July 03, 2016, 05:14:39 PM »
Looks like everything is heading @10% south[?]

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Re: Greenland 2016 Melt Season
« Reply #88 on: July 17, 2016, 11:53:27 AM »
Last big melt spike of the season coming up, as pressure systems align to draw some of the northern Baffin heat over Greenland.  On current forecast it looks like melt extent will approach 40% from the 19th through 21st or longer.

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Re: Greenland 2016 Melt Season
« Reply #89 on: July 21, 2016, 12:43:57 AM »
Last big melt spike of the season coming up, as pressure systems align to draw some of the northern Baffin heat over Greenland.  On current forecast it looks like melt extent will approach 40% from the 19th through 21st or longer.

Looks like you can see the effects of that Baffin bay heat on the west coast of Greenland. This is MODIS terra for 20th July on the area just south of Jakobshavn.


prokaryotes

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Re: Greenland 2016 Melt Season
« Reply #90 on: July 21, 2016, 01:11:20 AM »
The people who investigate and follow up on Greenland's ice melt should also take a close look at the potential of methane emissions connected to subglacial melting.

Molecular and biogeochemical evidence for methane cycling beneath the western margin of the Greenland Ice Sheet
Quote
Microbial processes that mineralize organic carbon and enhance solute production at the bed of polar ice sheets could be of a magnitude sufficient to affect global elemental cycles. To investigate the biogeochemistry of a polar subglacial microbial ecosystem, we analyzed water discharged during the summer of 2012 and 2013 from Russell Glacier, a land-terminating outlet glacier at the western margin of the Greenland Ice Sheet. The molecular data implied that the most abundant and active component of the subglacial microbial community at these marginal locations were bacteria within the order Methylococcales (59–100% of reverse transcribed (RT)-rRNA sequences). mRNA transcripts of the particulate methane monooxygenase (pmoA) from these taxa were also detected, confirming that methanotrophic bacteria were functional members of this subglacial ecosystem. Dissolved methane ranged between 2.7 and 83 μm in the subglacial waters analyzed, and the concentration was inversely correlated with dissolved oxygen while positively correlated with electrical conductivity. Subglacial microbial methane production was supported by δ13C-CH4 values between −64‰ and −62‰ together with the recovery of RT-rRNA sequences that classified within the Methanosarcinales and Methanomicrobiales. Under aerobic conditions, >98% of the methane in the subglacial water was consumed over ~30 days incubation at ~4 °C and rates of methane oxidation were estimated at 0.32 μm per day.

Our results support the occurrence of active methane cycling beneath this region of the Greenland Ice Sheet, where microbial communities poised in oxygenated subglacial drainage channels could serve as significant methane sinks.
http://www.nature.com/ismej/journal/v8/n11/full/ismej201459a.html

The region was at least during the sample time, a source of atmospheric methane. If there is a discussion on this topic somewhere here, please point me to it, thanks.

Related
https://en.wikipedia.org/wiki/Russell_Glacier_(Greenland)
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prokaryotes

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Re: Greenland 2016 Melt Season
« Reply #91 on: July 21, 2016, 11:30:42 PM »
Made a blog post

Ice sheet deglaciation and methane emissions, with the scope on Greenland’s melt season
Greenland's melt, what does it mean for future atmospheric methane?
http://climatestate.com/2016/07/21/ice-sheet-deglaciation-and-methane-emissions-with-the-scope-on-greenlands-melt-season/
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silkman

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Re: Greenland 2016 Melt Season
« Reply #92 on: July 22, 2016, 08:51:36 AM »
Melt extent, as forecast, went above 40% on July 20.


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Re: Greenland 2016 Melt Season
« Reply #93 on: August 03, 2016, 06:50:57 PM »
Per Jason Box's tweet today (see images) the darkness of Greenland in July 2016 was the 5th darkest of the past 17 Julys.
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etienne

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Re: Greenland 2016 Melt Season
« Reply #94 on: August 19, 2016, 12:01:29 AM »
Hello,

NSIDC has a new Greenland Cumulative melt day area graph. I once asked them if they could do something like that, maybe this could explain why it now exists.

This graph allows an easy comparison of different melt years.



Best regards,

Etienne

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Re: Greenland 2016 Melt Season
« Reply #95 on: August 19, 2016, 11:06:11 AM »
According to DMI this year has been a pretty average melting season in terms of surface mass balance. The melting area was even below average for most of the summer

Lennart van der Linde

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Re: Greenland 2016 Melt Season
« Reply #96 on: August 19, 2016, 11:48:26 AM »
According to DMI this year has been a pretty average melting season in terms of surface mass balance. The melting area was even below average for most of the summer

Pretty average compared to 1990-2013 yes, but above average compared to 1981-2010, according to NSIDC:
http://nsidc.org/greenland-today/

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Re: Greenland 2016 Melt Season
« Reply #97 on: August 20, 2016, 05:05:48 AM »
According to DMI this year has been a pretty average melting season in terms of surface mass balance. The melting area was even below average for most of the summer
This may be a stupid question, but why is the DMI mass balance for almost every year positive when the ice sheet is thinning?

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Re: Greenland 2016 Melt Season
« Reply #98 on: August 20, 2016, 05:29:43 AM »
According to DMI this year has been a pretty average melting season in terms of surface mass balance. The melting area was even below average for most of the summer
This may be a stupid question, but why is the DMI mass balance for almost every year positive when the ice sheet is thinning?

Not a stupid question at all.

Quote
.....The figure below shows the total daily contribution from all points on the ice sheet (top) and the same accumulated from September 1st to now (bottom). The blue curves show this season’s surface mass balance in gigatons (Gt; 1 Gt is one billion tons and corresponds to 1 cubic kilometer of water), and for comparison the mean curves from the historical model run are shown with two standard deviations on either side. Note that the accumulated curve does not end at 0 at the end of the year. Over the year, it snows more than it melts, but calving of icebergs also adds to the total mass budget of the ice sheet. Satellite observations over the last decade show that the ice sheet is not in balance. The calving loss is greater than the gain from surface mass balance, and Greenland is losing mass at about 200 Gt/yr.....

1GT is equal to a cubic kilometer

http://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/
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oren

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Re: Greenland 2016 Melt Season
« Reply #99 on: August 31, 2016, 01:12:41 AM »
Hello,

NSIDC has a new Greenland Cumulative melt day area graph. I once asked them if they could do something like that, maybe this could explain why it now exists.

This graph allows an easy comparison of different melt years.

Best regards,

Etienne

Good graph indeed.