Greenland experiences melting over 97% of its area in mid-July

What is worrisome is not a single event, but the pattern we have been having, esp. during a part of the climate cycle which is usually cooling.

http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2160

Posted by: Dr. Jeff Masters, 12:58 PM GMT on July 25, 2012 +43
Son Nghiem of NASA's Jet Propulsion Laboratory in Pasadena, CA, was analyzing radar data from the Indian Space Research Organisation's Oceansat-2 satellite last week when he noticed that 97% of Greenland appeared to have undergone surface melting on July 12--an event completely unprecedented in 30 years of satellite measurements. In a July 24 press release from NASA, Nghiem said, "This was so extraordinary that at first I questioned the result: was this real or was it due to a data error?" Multiple satellite data sets confirmed the remarkable event, though. Melt maps derived from three different satellites showed that on July 8, about 40 percent of the ice sheet's surface had melted, as a strong ridge of high pressure set up over Greenland. By July 12, the melting had expanded to cover 97% of Greenland. As I blogged about last week, temperatures at at the top of the Greenland Ice Sheet, 10,551 feet (3216 meters) above sea level, and 415 miles (670 km) north of the Arctic Circle, had risen above the freezing mark four times in the 12-year span 2000 - 2011. But in mid-July 2012, temperatures eclipsed the freezing mark on five days, including four days in a row from July 11 - 14. Interestingly, ice core records show that in 1889, a similar pronounced melt event occurred at the top of the Greenland Ice Sheet, and such events occur naturally about every 150 years. "But if we continue to observe melting events like this in upcoming years, it will be worrisome," said Lora Koenig, a NASA/Goddard glaciologist and a member of the research team analyzing the satellite data. Such an event could occur as early as this weekend: the latest wunderground forecast for the Greenland Summit calls for above-freezing temperatures to return again by Saturday through Tuesday, with a high of 36°F (2°C) on Tuesday. This would come close to the record warm temperature at Summit of 3.6°C set just two weeks ago. Exceptionally warm temperatures in Greenland this July have been made more likely by the fact that Arctic sea ice area has been at record low levels so far this month. Furthermore, the Greenland Ice Sheet has become darker this July than at any point since satellite measurements began (Figure 2), allowing Greenland to absorb more solar energy and heat up.