Increasing Antarctic Snowmelt Largest Potential for Sea Level Rise

In a new NASA study, researchers using 20 years of data from space-based sensors aboard satellites have confirmed that Antarctic snow is melting farther inland from the coast over time. It is melting at higher altitudes than ever and there is increasing melting on Antarctica's largest ice shelf.

Antarctica is so vast with such a varied topography that only satellites can actually capture the extent of changes in amount of snow melting across the many valleys, mountains, glaciers and ice shelves.

Antarctica has a limited area where snow melting is expected to occur because even during summer months most of Antarctica records temperatures well below zero. Yet, satellite data collected between 1987 and 2006 show snow melting in unlikely places. Snow melting was found as far inland as 500 miles away from the anrarctic coast. Similarly melting was found as high up as 1.2 miles above sea level in the Transantarctic Mountains.

The NASA study using 20-year old data records covered a time period three times longer than any previous studies. It reaffirmed through satellite data the extreme melting irregularities observed in 2005.

Antarctica has a surface size that is about 1.5 times the size of the United States. Within that vast area, Antarctica contains 90 percent of Earth's fresh water. This, of course, makes it the largest potential source of sea level rise. Significantly, the 20-year period studied showed that melting had increased on the Ross Ice Shelf that sits at the edge of the sea. This finding was in terms of the area affected by the increased melting and the duration of melting across affected areas--quantity and duration over expanse.

The satellite data was collected from the Special Sensor Microwave Imager radiometer aboard the Defense Meteorological Satellite Program's satellites. The microwave sensors showed evidence of persistent snow melting, which is defined as melting that occurs for at least three days or, alternatively, for one consecutive day and night.