J.E. Box1, J. Cappelen2, C. Chen1, D. Decker1, X. Fettweis3, T. Mote4, M. Tedesco5, R.S.W. van de Wal6, J. Wahr7
1 Byrd Polar Research Center, The Ohio State University, Columbus, Ohio, USA2 Danish Meteorological Institute, Copenhagen, Denmark
3 Department of Geography, University of Liège, Liège, Belgium
4 Department of Geography, University of Georgia, Athens, Georgia, USA
5 City College of New York, New York, NY, USA
6 Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, The Netherlands
7 Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado, USA
A report on the melting Greenland ice sheet on January 13, 2013, highlighted what can be a great future for mining on the huge island under Danish administration but with a regional government on its own. Excerpts below:
The duration of melting at the surface of the ice sheet in summer 2012 was the longest since satellite observations began in 1979, and a rare, near-ice sheet-wide surface melt event was recorded by satellites for the first time.
The lowest surface albedo observed in 13 years of satellite observations (2000-2012) was a consequence of a persistent and compounding feedback of enhanced surface melting and below normal summer snowfall.
Field measurements along a transect (the K-Transect) on the western slope of the ice sheet revealed record-setting mass losses at high elevations.
A persistent and strong negative North Atlantic Oscillation (NAO) index caused southerly air flow into western Greenland, anomalously warm weather and the spatially and temporally extensive melting, low albedo and mass losses observed in summer 2012.
In 2012, ice sheet surface melting set two new, satellite era records – melt extent and melt index – according to passive microwave observations made since 1979 (e.g., Tedesco, 2007, 2009). Melt extent is the fractional area (in %) of the surface of the ice sheet where melting was detected. The melt index (MI) is the number of days on which melting occurred multiplied by the area where melting was detected.
Melt extent over the Greenland ice sheet reached record values during 11-12 July, covering as much as ~97% of the ice sheet on a single day. Confirmed by different methods for analyzing passive microwave observations (e.g., Mote and Anderson, 1995; Tedesco, 2009), the almost 100% melt extent is nearly four times greater than the ~ 25% average melt extent that occurred in 1981-2010.