NASA scientists said that in 2005, west Antarctica experienced the worst ice melt ever recorded during three decades of observation using satellites.

The Antarctic melting was detected with NASA's QuikScat satellite and the affected regions encompassed an area as big as California.

The team which is led by Son Nghiem of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and Konrad Steffen, director of the Cooperative Institute for Research in Environmental Sciences at the University of Colorado, Boulder, measured snowfall accumulation and melt in Antarctica and Greenland from July 1999 through July 2005.

"Antarctica has shown little to no warming in the recent past with the exception of the Antarctic Peninsula, but now large regions are showing the first signs of the impacts of warming as interpreted by this satellite analysis," said Konrad Steffen of the University of Colorado. "Increases in snowmelt, such as this in 2005, definitely could have an impact on larger-scale melting of Antarctica's ice sheets if they were severe or sustained over time."

According to their findings, the South Pole melt occurred 900 kilometres inland, at high latitudes only 500 kilometres from the South Pole and at elevations of 2,000 metres, where "melt had been considered unlikely". Air temperatures were abnormally high, reaching 5 degrees Celsius at one point and remaining above the melting point for a week.

Changes in the ice mass of Antarctica important to understanding global sea level rise. Â Large amounts of Antarctic freshwater flowing into the ocean also could affect ocean salinity, currents and global climate.

Nghiem said while no further melting had been detected through March 2007, more monitoring is needed. "Satellite scatterometry is like an X-ray that sees through snow and finds ice layers beneath as early as possible," he said. "It is vital we continue monitoring this region to determine if a long-term trend may be developing.