Satellite Data Reveals Extreme Summer Snowmelt in Arctic
The northern part of the Greenland ice sheet experienced extreme snowmelt during the summer of 2008, with large portions of the area subject to record melting days, according to Dr. Marco Tedesco, Assistant Professor of Earth & Atmospheric Sciences at The City College of New York (CCNY), and colleagues. Tedesco explains to The Daily Galaxy that he doesn’t know for certain if this rapid snowmelt suggests that global warming might be happening faster than predicted? “At this stage of the analysis it is not possible to draw any conclusion in this regard,” he noted. Professor Tedesco and his colleagues are currently analyzing possible causes for the high snowmelt in northern Greenland. High surface temperatures are, so far, the most evident factor. However other factors, such as solar radiation, could play a role, as well, he noted.
The team discovered the rapid snowmelt based on an analysis of microwave brightness temperature recorded by the Special Sensor Microwave Imager (SSM/I) onboard the F13 satellite. Tedesco told The Daily Galaxy that he does not know what animal species may be affected by this extreme melting, since that is not his field of work, but from a climate perspective he finds the melting to be unusual.
“Having such extreme melting so far north, where it is usually colder than the southern regions is extremely interesting,” Professor Tedesco said. “In 2007, the record occurred in southern Greenland, mostly at high elevation areas where in 2008 extreme snowmelt occurred along the northern coast.”
Tedesco says that the runoff is 88 percent higher than the 1979 – 2007 mean. In addition, analysis of ground measurements from World Meteorological Organization automatic weather stations located close to where the record snowmelt was observed indicate surface/air maximum temperatures up to 3° Celsius above average.
Melting in northern Greenland lasted up to 18 days longer than previous maximum values. The melting index, i.e. the number of melting days times the area subject to melting) was three times greater than the 1979–2007 average, with 1.545•106 square kilometers x days.
The snowmelt and temperature anomalies occurred near Ellesmere Island, where several ice shelf break-ups were observed this summer. The region where the record melting days were recorded includes the Petermann glacier, which lost 29 square kilometers in July.
“The consistency of satellite, model and ground-based results provides a basis for a more robust analysis and synthesis tool,” Professor Tedesco added. Next June, he and his colleagues plan to conduct field work in northern Greenland to further study the phenomenon.
There is an increasing impression that at north and south poles the temperature is increasing while it is somewhat decreasing at medium latitudes on north emisphere (e.g. Italy).
Long term data are Not yet available and relation with minimum of solar sunspot uncertain.
As a matter of facts the writer is right : north pole ice is melting at an increasing rate.
The article is simple and well done.
Posted by: claudio | October 13, 2008 at 12:37 PM