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2014 Greenland ice sheet reflectivity near record low

The NASA MODIS sensor on the Terra satellite provides surface reflectivity data since early 2000 enabling us to evaluate just how dark Greenland ice is today and in comparison with the past 14 years.

The data show that 2014 ice sheet reflectivity (also called albedo) has been near record low much of 2014, especially at the highest elevations.

2500-3200m_Greenland_Ice_Sheet_Reflectivity

15 years of albedo data for the uppermost region of the ice sheet

The darkness of the surface at high elevations is consistent with the findings of Dumont et al. (2014) that an increasing dust concentration on the ice sheet in the pre-melt season from decreasing snow cover on land upwind of the ice sheet may be a significant darkening factor.

If there will be a persistent pattern of warm air brought over the ice sheet as in 2012, we should expect melting at the ice sheet upper elevations. Why? Low reflectivity heats the snow more than normal, removing more of the ‘cold content’. A dark snow cover will thus melt earlier and more intensely. A positive feedback exists for snow in which once melting begins, the surface gets yet darker due to increased liquid water content, increased snow grain size, and possible other factors such as microbial growth.

For the ice sheet as a whole, low reflectivity in 2014 has been exceeded only by years 2012, 2013, and 2011, depending on the time of year…

0-3200m_Greenland_Ice_Sheet_Reflectivity

15 years of albedo data for the entire ice sheet and peripheral glaciers

The Greenland reflectivity anomaly map features red and orange colors that indicate a relatively dark surface near the end of June especially at the low elevations where most melting occurs.

albedo anomaly map

albedo anomaly map. For more, see http://polarportal.dk/en/groenlands-indlandsis/nbsp/isens-overflade/

Work Cited

  1. Dumont, M., E. Brun, G. Picard, M. Michou, Q. Libois, J-R. Petit, M. Geyer, S. Morin and B. Josse, Contribution of light-absorbing impurities in snow to Greenland’s darkening since 2009, Nature Geoscience, 8 June, 2014, DOI: 10.1038/NGEO2180

About the author Jason Box

Dr. Jason Box has been investigating Greenland ice sheet sensitivity to weather and climate as part of 23 expeditions to Greenland since 1994. His time camping on the inland ice exceeds 1 year. Year 2012 brought a deeper level of insight as the scientific perspective shifts to examine the interactions ice with atmospheric and ocean systems, including the role of fire in darkening the cryosphere. As part of his academic enterprise, Box has authored or co-authored 50+ peer-reviewed publications related to Greenland cryosphere-climate interactions. Box instructed climatology courses at The Ohio State University 2003-2012. Box is now a Professor at the Geological Survey of Denmark and Greenland (GEUS). Box was a contributing author to the Nobel Peace Prize-winning Intergovernmental Panel on Climate Change 2007 4th assessment report. Box is also the former Chair of the Cryosphere Focus Group of the American Geophysical Union.

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