According to a report from NASA, satellite observations of Greenland’s ice cap reveal that it has melted more this summer than at any time since satellite observations began about thirty years ago.
Iceland is covered by a massive sheet of ice, almost two miles thick in some places. In summer months, melting of the ice, especially near the surface, is expected, but satellite observations show that over the course of this summer, nearly 97 percent of Greenland’s ice underwent surface melting.
Speaking to the BBC, Dr .Poul Christoffersen, of the Scott Polar Institute, said, “The melting seen in the satellite data is unprecedented …. The observation is in my view much more important than the recently reported break up of a large iceberg from Petermann Glacier.”
Son Nghiem of NASA’s Jet Propulsion Laboratory first observed the change in radar data from the Indian Space Research Organisation’s Oceansat-2 satellite. Surprised, he checked his observations with other scientists using other satellite observations. Mr. Nghiem said, “This was so extraordinary that at first I questioned the result: was this real or was it due to a data error?” The observations from the other satellites confirmed his initial observations. On July 8, the satellite data shows melting in 40 percent of the ice’s surface, which increases to 97 percent by July 12.
Thomas Mote, a climatologist at the University of Georgia, notes that the melting coincided with the arrival of a series of domes or ridges of especially warm air over Greenland during the days when the melting occurred. “Each successive ridge has been stronger than the previous one,” said Mr. Mote.
According to a study of ice cores by Kaitlin Keegan of Dartmouth University, similar melting last occurred in 1889. Goddard Spaceflight Center glaciologist Lora Koenig says, “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.” She adds, “But if we continue to observe melting events like this in upcoming years, it will be worrisome.”
Tom Wagner, a manager of NASA’s cryosphere program, says, “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. Satellite observations are helping us understand how events like these may relate to one another as well as to the broader climate system.”
Thomas Mote, a climatologist at the University of Georgia, notes that the melting coincided with the arrival of a series of domes or ridges of especially warm air over Greenland during the days when the melting occurred. “Each successive ridge has been stronger than the previous one,” said Mr. Mote.
According to a study of ice cores by Kaitlin Keegan of Dartmouth University, similar melting last occurred in 1889. Goddard Spaceflight Center glaciologist Lora Koenig says, “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.” She adds, “But if we continue to observe melting events like this in upcoming years, it will be worrisome.”
Tom Wagner, a manager of NASA’s cryosphere program, says, “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. Satellite observations are helping us understand how events like these may relate to one another as well as to the broader climate system.”
No comments:
Post a Comment