The_Global_Warmer Posted August 12, 2014 Author Share Posted August 12, 2014 Based on the albedo/grace data the melt has been large. We can see ground truth to this in terms of albedo being low. There is still melt ponds and a very distinguishable area of melting ice above the dirty ice layer. At the bottom of the image you can see water logged ice or snow as well. On this version we can see the dry snow area is well above the 2000M mark over the Southern 1/3rd of GIS. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted August 18, 2014 Author Share Posted August 18, 2014 Link to comment Share on other sites More sharing options...
LithiaWx Posted August 20, 2014 Share Posted August 20, 2014 Benign Melt again for 2014 just like 2013. Link to comment Share on other sites More sharing options...
nflwxman Posted August 20, 2014 Share Posted August 20, 2014 Benign Melt again for 2014 just like 2013. greenland_melt_area_plot.png Huh? It's over the average quite a bit. Am I missing something or are you just trying to get to Friv? Link to comment Share on other sites More sharing options...
PhillipS Posted August 21, 2014 Share Posted August 21, 2014 Benign Melt again for 2014 just like 2013. greenland_melt_area_plot.png Can you help us understand how you reached that opinion? As nflwxman pointed out the surface melt is well above the long-term average. And here is the PolarPortal comparison with 2012: So, based on the data, the 2014 melt season should be close to the record 2012 mass loss, and will certainly be well above 2013. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted August 22, 2014 Author Share Posted August 22, 2014 Looks super benign. August is going to rival or beat 2010 for lowest albedo on GIS record when the data comes in. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted August 22, 2014 Author Share Posted August 22, 2014 The benign melt season continues to show benign results with melt area going back to 3SD+ anomalies. It couldn't be any more benign then this. We had about 10 exciting days since June 1st when melt area fell every so slightly below normal. The rest of the Summer has seen endless benign above normal melt area days. Seriously tho. How benign is this. Like 70% of the ice sheet had almost no melt activity. Snooze. Link to comment Share on other sites More sharing options...
bluewave Posted August 22, 2014 Share Posted August 22, 2014 Can you help us understand how you reached that opinion? As nflwxman pointed out the surface melt is well above the long-term average. And here is the PolarPortal comparison with 2012: So, based on the data, the 2014 melt season should be close to the record 2012 mass loss, and will certainly be well above 2013. They still have the wrong plot posted for 2012. This year will be worse than 2013, but well behind the record melt of 2012. Link to comment Share on other sites More sharing options...
nflwxman Posted August 22, 2014 Share Posted August 22, 2014 They still have the wrong plot posted for 2012. This year will be worse than 2013, but well behind the record melt of 2012. Mass_tot_Large_en-1024x792.png That plot only looks updated to early July? Link to comment Share on other sites More sharing options...
ORH_wxman Posted August 22, 2014 Share Posted August 22, 2014 That plot only looks updated to early July? No, he's posting a shot of 2013 to show that the red line that is labeled "2012" on the latest version of the map is in fact 2013...and the true 2012 line is much higher melt. Notice how the "2012" red line on this year's map traces the blue "2013" line on last year's version up to the point where it was updated in that particular screenshot. Thus, the line labeled "2012" on this year's map is actually 2013. This makes sense anyway...there's no way 2014's melt would be like 2012 with the monstrous difference in temperatures and sfc melt. Being a bit above 2013's melt on Greenland makes more sense. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted August 22, 2014 Author Share Posted August 22, 2014 It's not wrong. It has been updated. The newer ones show less melt for 2012. Link to comment Share on other sites More sharing options...
ORH_wxman Posted August 22, 2014 Share Posted August 22, 2014 It's not wrong. It has been updated. The newer ones show less melt for 2012. How do you know it is correct? Did DMI issue a statement that it had been revised? It tracks identical with 2013's line that bluewave showed through early July. To me, it looks like they have 2013 on there mis-labeled as 2012. Unless by coincidence, the "revised" 2012 melt was identical to 2013 from March through early July. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted August 22, 2014 Author Share Posted August 22, 2014 How do you know it is correct? Did DMI issue a statement that it had been revised? It tracks identical with 2013's line that bluewave showed through early July. To me, it looks like they have 2013 on there mis-labeled as 2012. Unless by coincidence, the "revised" 2012 melt was identical to 2013 from March through early July. Someone from DMI posted about it on Nevens forum in this thread. I can't remember which page it is on. https://forum.arctic-sea-ice.net/index.php/topic,848.0.html It can't be 2013 because the chart is based on Albedo. Here is the accompanying chart where you can see it uses a method with the inverse of albedo. I would assume 2014 is higher because of May which means it's probably overdone. But this graphic matches albedo for 2014 and 2012. The 2014 line moves around each time it updates back into June and July at times. My guess is with preliminary grace data but I am not sure. Maybe this one is with 2013. But the one above this is definitely 2012 and 2014. The main problem is 2014 has been below 2013 the entire summer even going back to May. The figures are based on two different methods: Method 1 is based on monthly measurements of changes in gravity. Gravity changes as the amount of ice changes and this can be detected by the GRACE satellites. Scientists at DTU Space have contributed to developing the methods used to derive ice mass changes from the gravity changes. The raw GRACE satellite data is carefully processed and validated before it is released to the user, and the product presented here might be delayed by 2-3 months. See Barletta et al. 2013.Method 2 is developed by scientists at GEUS and combines past gravity measurements from GRACE with satellite measurements of ice-reflectivity (albedo) and this makes it possible to get near-real-time estimates of the total mass change. The albedo data is retrieved from the MODIS sensor on the NASA Terra satellite. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted August 22, 2014 Author Share Posted August 22, 2014 I haven't been following the weather around GIS recently but albedo is remarkably low. That area over Southern GIS is just huge. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted August 22, 2014 Author Share Posted August 22, 2014 Then it is wrong for 2014 as well because 2014 should have passed 2013 a while back Link to comment Share on other sites More sharing options...
ORH_wxman Posted August 22, 2014 Share Posted August 22, 2014 Someone from DMI posted about it on Nevens forum in this thread. I can't remember which page it is on. https://forum.arctic-sea-ice.net/index.php/topic,848.0.html It can't be 2013 because the chart is based on Albedo. Here is the accompanying chart where you can see it uses a method with the inverse of albedo. I would assume 2014 is higher because of May which means it's probably overdone. But this graphic matches albedo for 2014 and 2012. The 2014 line moves around each time it updates back into June and July at times. My guess is with preliminary grace data but I am not sure. Maybe this one is with 2013. But the one above this is definitely 2012 and 2014. The main problem is 2014 has been below 2013 the entire summer even going back to May. It is the last graph you psoted where the questions were asked...not the others. The only thing I found in that thread was this: 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. This suggests why perhaps the 2013 line stops in July on the original graph bluewave posted...but it does not explain about any revision made to 2012 data. Clearly in bluewave's original graph, 2012 has a way higher sea-level contribution than this year's graph is claiming. So either 2012's data was grossly revised downwards (still waiting for an explanation on why if this is the case)...or this year's graph is actually plotting a version of 2013 with the missing months filled in. Given that this year's graph has 2012 suspiciously tracking almost dead nuts with 2013 on the prior graph, I suspect the latter scenario is the case. Especially if you say the model is based on albedo....how can easily the lowest albedo year on record have the same melt as 2013 which was only slightly below the 2000-2009 average? Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted August 22, 2014 Author Share Posted August 22, 2014 It says method one is based on monthly changes in gravity. Method 1 is based on monthly measurements of changes in gravity. Gravity changes as the amount of ice changes and this can be detected by the GRACE satellites. Scientists at DTU Space have contributed to developing the methods used to derive ice mass changes from the gravity changes. The raw GRACE satellite data is carefully processed and validated before it is released to the user, and the product presented here might be delayed by 2-3 months. See Barletta et al. 2013. This graphic posted in this thread shows the blue line above the red line. The graphic posted today shows them locked together. And then it was revised. Link to comment Share on other sites More sharing options...
chubbs Posted August 22, 2014 Share Posted August 22, 2014 The monthly and accumulated DMI charts are not self consistent so do not trust either. Will need to wait for GRACE data to compare 2014 to recent years. Link to comment Share on other sites More sharing options...
ORH_wxman Posted August 22, 2014 Share Posted August 22, 2014 The monthly and accumulated DMI charts are not self consistent so do not trust either. Will need to wait for GRACE data to compare 2014 to recent years. Yes, I wouldn't trust any of these graphs with the mass balance and sea level contribution. They seem to be frequently revised and/or mis-labeled....and of course, they are based on some pretty complex formulas without much ground data. Definitely less trustworthy than things like sea ice extent/area. Even sea ice volume I'd trust a lot more than these. That's not to say these graphs are useless, but they are probably several years away from getting accurate enough to use in real time. The most accurate ones are probably the melt area graphs...since those would be the least complex. Link to comment Share on other sites More sharing options...
bluewave Posted August 22, 2014 Share Posted August 22, 2014 Yes, I wouldn't trust any of these graphs with the mass balance and sea level contribution. They seem to be frequently revised and/or mis-labeled....and of course, they are based on some pretty complex formulas without much ground data. Definitely less trustworthy than things like sea ice extent/area. Even sea ice volume I'd trust a lot more than these. That's not to say these graphs are useless, but they are probably several years away from getting accurate enough to use in real time. The most accurate ones are probably the melt area graphs...since those would be the least complex. It looks like we will finish above last year but well below 2012. Maybe in the 50-100 range? Link to comment Share on other sites More sharing options...
chubbs Posted August 22, 2014 Share Posted August 22, 2014 In any case this recent paper indicates Greenland volume loss rates increased by factor of 2.5 between 2003-2009 and Jan 2011 - Jan 2014. Iceberg discharge may be more important than surface melt since the biggest losses are concentrated in major glacier drainage basins. http://static2.egu.eu/media/filer_public/ac/f2/acf2d697-4a67-433b-bfd4-2a1f569cdb86/tc-2014-18.pdf Link to comment Share on other sites More sharing options...
tacoman25 Posted August 23, 2014 Share Posted August 23, 2014 Regardless, all Greenland melt charts will be headed sharply downwards shortly. The big island goes in the freezer in a couple of days. I doubt 2014 looks much like 2010 come September. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted August 23, 2014 Author Share Posted August 23, 2014 2014 had the 3rd lowest albedo behind 2011 and 2012 in June. It was virtually tied with 2011 for 2nd lowest in July. And it's shaping up to be virtually tied or below 2012 in August for lowest on record. This has been driven by record low albedo over parts of the Northern 1/3rd of GIS where record temps have also been recorded. So in terms of ice mass loss we are likely looking at something near 2011. This image from Jason Box twitter shows it all. If GIS wasn't so dark in the ice loss zone the surface would be gaining mass every year. Link to comment Share on other sites More sharing options...
PhillipS Posted August 23, 2014 Share Posted August 23, 2014 Regardless, all Greenland melt charts will be headed sharply downwards shortly. The big island goes in the freezer in a couple of days. I doubt 2014 looks much like 2010 come September. Just remember that the GIS mass loss due to glacial calving doesn't stop any time soon. If you focus just on surface melt you're missing the big picture. Link to comment Share on other sites More sharing options...
chubbs Posted August 24, 2014 Share Posted August 24, 2014 The charts posted by bluewave above (assuming years are correct) indicate that 2014 is roughly splitting the difference between 2013 and 2012 at the last point plotted. Link to comment Share on other sites More sharing options...
stadiumwave Posted August 24, 2014 Share Posted August 24, 2014 This June and July were among the cooler ones for Greenland since 2007. T.png 2007 1.803 2008 1.885 2009 1.136 2010 1.907 2011 1.726 2012 2.466 2013 0.571 2014 1.229 Pretty amazing how Greenland air temps are affected by the AMO phases. Link to comment Share on other sites More sharing options...
The_Global_Warmer Posted August 25, 2014 Author Share Posted August 25, 2014 And yet ice mass loss from surface melt will double 2009 since the average temp over the whole of GIS is not very telling. 15% of GIS is responsible for 90%+ of the topical ice mass loss each summer. Pretty easy math I'd say. Link to comment Share on other sites More sharing options...
tacoman25 Posted September 3, 2014 Share Posted September 3, 2014 And...just like that, it's over. Link to comment Share on other sites More sharing options...
thetonynator Posted September 3, 2014 Share Posted September 3, 2014 And...just like that, it's over. Screenshot_1.jpg Why use a 20 year average when there is a 30 year available? Link to comment Share on other sites More sharing options...
FloridaJohn Posted September 3, 2014 Share Posted September 3, 2014 Just goes to show how slow the current melt rates of around 1 mm of sea level rise a year are compared to some of the projections out there around 2100. We would need to really accelerate the current melt rates to get to the year 2100 projections. And we all know how uncertain model projections of temperature have been since the late 90's. So a slower amount of warming by 2100 would have even slower melt rates. http://sciencenordic.com/greenland-meltdown-could-slow-down The total loss of ice from the four glaciers alone in the moderate scenario will raise sea levels by 8.5 to 13 millimetres by the year 2100. From the article: "She and seven other researchers used a new model to simulate the effect of the changing climate on the Petermann, Kangerdlugssuaq, Helheim and Jakobshavn Isbræ glaciers out to the year 2200. These four glaciers transport ice from more than 20 percent of the Greenland ice sheet. “A crucial fact is that these two scenarios are equally probable. So the extreme variation could be more correct than the more moderate one. This is rather frightening when we find that the warmer scenario results in a 50 percent greater loss of ice from the Greenland glaciers by the end of the 22nd century,” says Nick. The total loss of ice from the four glaciers alone in the moderate scenario will raise sea levels by 8.5 to 13 millimetres by the year 2100. In the more extreme scenario, the rise due to the melting of the glaciers will be between 11 to 17.5 millimetres." That melt rate accounts for only 20 percent of the total Greenland melt rate, and as noted by the scientists who did this study, the worse case scenario is just as likely as the best case scenario. Link to comment Share on other sites More sharing options...
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