2007 Annual Meeting and Arctic Forum | Abstracts

Melting Over the Greenland Ice Sheet in 2006 and the 2003 - 2006 Melting Anomaly from Space-Borne Microwave Data

Marco Tedesco^1
1JCET, NASA/University of Maryland Baltimore County, NASA GSFC, code 614.6, Greenbelt, MD, 20771, USA, Phone 301-614-5717, Fax 301-614-5558, mtedesco@umbc.edu

Greenland is the world's largest island, containing the second largest glacier on Earth (the Inland Ice) with a surface extent of approximately 1.75 million Km2. It is also the largest relic of the Ice Age in the Northern Hemisphere, containing enough ice to rise the sea level of around 7 m. Recently, the Intergovernmental Panel on Climate Change (IPCC, available at http://www.ipcc.ch/SPM2feb07.pdf) estimated contribution to the sea level rise from the Greenland ice sheet at 0.21 mm/year, representing 7.5% of the sum of individual climate contributions to sea level rise (2.8 mm/year) and 6.7% of the observed total sea level rise.

Wet and dry snow have different physical properties, although they appear to be very similar at first look. Scientists agree that the presence of liquid water within the snowpack causes more incoming solar radiation to be absorbed than dry snow. Hence, as Greenland is very sensitive to changes in the climatic forcing, a rise in the temperature will increase the areal extent of surface snowmelt. This decreases the amount of solar energy reflected back to space, which, in turn, will increase the energy absorbed by the Earth. Also, recent studies show that melting snow enhances sliding of glaciers as surface meltwater seeps down to the ice-bedrock interface. Furthermore, increased melting liberates water that can freely evaporate; this may increase cloud cover, which is associated with its own complex set of climate feedbacks.

In this poster, I will show maps of melt extent and duration in 2006 over the Greenland ice sheet derived from space-borne microwave brightness temperatures measured by the Special Sensor Microwave Imaging radiometer (SSM/I). I will also show temporal trends of daily melting areas from which distinct events regarding the onset melting and freezing can be identified. A long-term analysis for the period 1988-2006 shows that 2006 ranked seventh or fifth, depending on the frequency, within the study period. Lastly, melting anomalies for the period 2003-2006 will be displayed, showing consistent results with those regarding mass loss, altitude or surface temperature changes from other satellites mission, such as GRACE., ICESat and MODIS.