Greenland Ice Sheet Surface Melting Rapidly
Due to the altering climatic conditions, the entire ice cover of Greenland experienced some degree of melting at its surface.
A latest observation made NASA and the University scientists, with the help of three independent satellites show that Greenland's surface ice cover melted over a larger area than at any time in more than 30 years of satellite observations. Nearly the entire ice cover of Greenland, from its thin, low-lying coastal edges to its two-mile-thick center, experienced some degree of melting at its surface.
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It was in this month that, a huge chunk of iceberg twice the size of Manhattan parted from Greenland's Petermann glacier signifying another dramatic change in the environment due to global warming or climate change and rise in ocean temperatures. Prior to this it was in the year 2010 that Peterman glacier lost an area of roughly 97 square miles compared with 2012 split that measured 46 square miles.
It is normal that about half of the surface of the Greenland's ice sheet melts. And this melted water quickly refreezes at high elevations. And only some of this melt water is retained by the ice sheets near the coast while the rest is lost into the ocean. But this year was different as the scientist noticed a dramatic alteration, as the ice melting at or near surface increased. The data suggests that nearly 97 percent of the ice sheet surface thawed at some point in mid July. The researchers are still probing into this issue to determine whether rate at which the ice is melting due to global warming, will affect the overall volume of ice loss this summer and cause the sea levels to rise.
"The Greenland ice sheet is a vast area with a varied history of change. This event, combined with other natural but uncommon phenomena, such as the large calving event last week on Petermann Glacier, are part of a complex story," said Tom Wagner, NASA's cryosphere program manager in Washington. "Satellite observations are helping us understand how events like these may relate to one another as well as to the broader climate system."
Analyzing the radar data from the Indian Space Research Organization's (ISRO) Oceansat-2 satellite last week, Son Nghiem of NASA's Jet Propulsion Laboratory in Pasadena, Calif., noticed something alarming. He noticed picture of Greenland changed. Most of the Greenland appeared to have undergone surface melting on July 12. Nghiem said, "This was so extraordinary that at first I questioned the result: was this real or was it due to a data error?"
Ngheim along with Dorothy Hall at NASA's Goddard Space Flight Center in greenbelt, Md studied the surface temperature of Greenland with the help of Moderate resolution Imaging Spectroradiometer ( MODIS) on NASA's Terra and Aqua satellites. Hall confirmed that MODIS showed unusually high temperature and that melt was extensive over the ice sheet surface.
Based on the data derived from the three satellites, the melt maps showed that on Jul 8 about 40 percent of the ice sheet's surface had melted. And they noticed nearly 97 percent ice had already melted by July 12.
This extreme melt event coincided with an unusually strong ridge of warm air, or a heat dome, over Greenland. The ridge was one of a series that has dominated Greenland's weather since the end of May.
"Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time," says Lora Koenig, a Goddard glaciologist and a member of the research team analyzing the satellite data. "But if we continue to observe melting events like this in upcoming years, it will be worrisome."