West Antarctica Melt
NASA scientists, teaming with scientists from the University of Colorado at Boulder, have discovered evidence that clearly shows large areas in West Antarctica in which snow melted during January 2005 due to the warm temperatures, up to 41 degrees Fahrenheit in one area. According to NASA, the melting was the first ever discovered by NASA’s QuikScat satellite, and the largest observed by satellites in the last three decades.
Data from QuikScat enabled researchers to measure accumulated snow and the melting in Antarctica and Greenland for 6 years, from July 1999 until July 2005. Except for the area of the Antarctic Peninsula, little or no warming has been seen in Antarctica in the recent past, but that changed with large areas showing signs of warming and increased snow melt. The melting of the ice was seen in different areas with varying latitudes and elevations where melting had not been expected, such as 560 miles inland from the open ocean, 310 miles from the South Pole and at elevations above 6,600 feet. Although the melting covered an area about the size of California, the melt did not last long enough for the water to reach the ocean.
The QuikScat satellite was able to detect the changes in the ice sheet resulting from the thawing and subsequent refreezing of the ice by means of reflected radar pulses. Using the differences shown in various areas of ice, a map of the continent’s snowmelt was created. Information obtained by QuikScat, data collected by other NASA satellites, as well as ground and aircraft measurements can combine to give a more complete picture of the changing status of the ice sheets.
All the ice on Earth if melted would raise sea levels by 200 feet. Greenland would account for 20 feet, with Antarctica contributing almost all the rest. Even if the complete melting of the continent’s ice is not expected, even a small amount of melting could affect coastal environments. Also, any significant melting of the ice, with subsequent large amounts of fresh water entering the ocean, could affect the salinity of the water, followed by changes in ocean currents, and ultimately affect the global climate.
Another concern is the effect the melting ice has on the movement of the ice sheets toward the ocean. Water from snow melt can percolate down through cracks in the ice to the bedrock where it provides a layer of water on which the ice can more easily move, thus increasing the speed at which the ice travels. Upon reaching the ocean, the ice would raise sea levels. Although no additional melting had been observed through March 2007, continued observation is required to learn if a long-term trend is beginning.
This entry was posted on Monday, June 25th, 2007 at 12:39 am and is filed under Space Agency News, Technical Concerns. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
