Terrestrial Cryosphere Summary
Section Coordinator: Marco Tedesco
City College of New York, New York, NY, USA
November 15, 2012
|June 2012 snow extent anomaly. Brown colors indicate areas of greatest loss compared to the average snow extent. Large snow map available from NOAA Climate.gov.|
In 2012, several terrestrial cryosphere records were set. New minimum snow cover extent values occurred over the Northern hemisphere in June, when snow still covers most of the Arctic region, and over Eurasia in May. The rate of loss of June snow cover extent, -17.6%/decade during the period of satellite observation (1979-2012), was a new record relative to the 1979-2000 mean value, and greater than that of September sea ice extent (-13.0%/decade) during the same period. Snow cover duration was the second shortest on record. New record high temperatures at 20 m depth were measured at most permafrost observatories on the North Slope of Alaska and in the Brooks Range, Alaska, where measurements began in the late 1970s.
In Greenland, melting at the surface set a new record and in some locations lasted up to ~2 months longer than the average for the period of 1979-2011. An exceptional event was recorded in July 2012, when melting occurred over ~97 % of the Greenland ice sheet. Albedo (reflectivity) estimated from satellite measurements (2000-2012) and mass losses measured in situ at high elevations also set new records in Greenland.
|Greenland surface melt extent on July 1 & 11, 2012, based on SSM/I data provided by Tom Mote. Blue color indicates area of surface melt. Large surface melt maps available from NOAA Climate.gov.||Summer (JJA) albedo anomaly in 2012. Darker blue colors show areas with lower reflectivity relative to the 2000-2011 reference period. Based on data derived from MODIS observations. (Hunter) Large reflectivity map available from NOAA Climate.gov.|
Outside Greenland, nineteen of twenty Arctic glaciers reported by the World Glacier Monitoring Service had a negative mass balance for the 2009-2010 balance year, and, in the 2010-2011 balance year the mass losses from the four Canadian Arctic glaciers were the greatest on record. Consistent with the in situ measurements, the GRACE satellite-derived mass loss in 2010-11 from all the glaciers and ice caps in the Canadian Arctic Islands was the largest for this region since GRACE observations began in 2002.