Greenland ice sheet record surface melting underway
While the potential impact of wildfires on darkening the Greenland ice sheet surface remain to be resolved, there is mounting evidence of an extreme year 2012 melt.
Melt signatures from active microwave remote sensing are stronger than in recent years over the upper areas of the ice sheet. Dark areas indicate absorption of the microwave signal emitted by the satellite. While, year 2010 and 2011 are recognized as being record melt years (Tedesco et al. 2011, van As et al. 2011), year 2012 melting appears to be more extensive. Reported here, a Japanese field team observed a slushy surface at 1500 m and rainfall while examining satellite observations similar to that below.
On July 12, 2012, the Watson River bridge in Kangerlussuaq, west Greenland, has been swamped by higher river levels than have been observed. Watch the stunning videos here and here.
An elevated occurrence of above melting temperatures are observed 11-14 July near the ice sheet topographic summit in an area typically considered to be melt-free, a.k.a. the “dry snow zone”. The dates of a 4 consecutive days with near-surface air temperature above melting at the Summit station coincide with the Watson river flooding.
In my recently accepted albedo paper (Box et al. 2012, below), see abstract, the statement: “it is reasonable to expect 100% melt area over the ice sheet within another similar decade of warming.” may be coming true already.
Box, J. E., Fettweis, X., Stroeve, J. C., Tedesco, M., Hall, D. K., and Steffen, K.: Greenland ice sheet albedo feedback: thermodynamics and atmospheric drivers, The Cryosphere, 6, 821-839, doi:10.5194/tc-6-821-2012, 2012. open access
Acknowledements
Thanks to Chris Biscan via Neven’s Arctic Sea Ice Blog for identifying an accessible source of Advanced Scatterometer (ASCAT) data.
- Box, J. E., Fettweis, X., Stroeve, J. C., Tedesco, M., Hall, D. K., and Steffen, K.: Greenland ice sheet albedo feedback: thermodynamics and atmospheric drivers, The Cryosphere Discuss., 6, 593-634, doi:10.5194/tcd-6-593-2012, 2012.
- Tedesco, M., Fettweis, X., van den Broeke, M. R., van de Wal, R. S. W., Smeets, C. J. P. P., van de Berg, W. J., Serreze, M. C., and Box, J. E.: The role of albedo and accumulation in the 2010 melting record in Greenland, Environ. Res. Lett., 6, 014005, http://dx.doi.org/10.1088/1748- 9326/6/1/014005doi:10.1088/1748-9326/6/1/014005, 2011.
- van As, D., Hubbard, A., Hasholt, B., Mikkelsen, A. B., van den Broeke, M., and Fausto, R. S.: Surface mass budget and meltwater discharge from the Kangerlussuaq sector of the Greenland ice sheet during record-warm year 2010, The Cryosphere Discuss., 5, 2319–2347, http://dx.doi.org/10.5194/tcd-5- 2319-2011doi:10.5194/tcd-5-2319-2011, 2011.
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July 24th, 2012 at 5:47 am
Hi Jason
The ASCAT image from July 12th 2012 looks really dark:
http://manati.star.nesdis.noaa.gov/datasets/ASCATData.php
At NEEM people were struggling with water:
http://neem.dk/field_diaries/field_diaries_2012/2012_07_12/
(and days around then)
Reportedly the snowballs were excellent.
July 24th, 2012 at 8:43 pm
[...] Neven’s Arctic Sea Ice blog notes that “In the meantime Dr. Jason Box reports on the Meltfactor blog“: [...]
July 25th, 2012 at 7:02 am
[...] on Mittivakkat Glacier by Mernild et al (2011). The summer of 2012 has every indication of being a record melt year for much of the Greenland Ice Sheet, and this will certainly have an impact going forward on De [...]
July 25th, 2012 at 7:23 am
Excellent work on documenting the albedo changes, that you expected to see, though not of this magnitude so suddenly I am sure. The high summer melt rate has led to the mot rapid filling of Tiningnilik Lake .
July 25th, 2012 at 8:17 pm
[...] University’s Byrd Polar Research Center who has been following the low reflectivity trends, wrote on his blog that he projects a 100 percent melt area in Greenland “within another similar decade of [...]