Washington, Oct 7 : Arctic sea ice extent in 2009 was the third lowest since satellite measurements were first made in 1979.

The National Snow and Ice Data Center (NSIDC) in Boulder, Colorado, said its annual end-of-summer observation showed the North Pole ice sheet covered 5.36 million square kilometres.

The figure represented a 1.06-square-kilometre recovery from the record low of 2007. The second lowest measurement was in 2008.

NSIDC is sponsored by several U. S. government agencies, including NASA. Ice data are derived from measurements made by U. S. Department of Defense and NASA satellites, with key work in interpreting the data and developing the 30-year history done by scientists at NASA''s Goddard Space Flight Center in Greenbelt, Md.

"The changes from year to year are interesting since there has been large variability," said Josefino Comiso, a sea ice expert at NASA Goddard.

"But we need to look at several years of data to examine the long-term trends. Our three decades of continuous satellite measurements show a rapid decline of about 11.6 percent per decade," Comiso said.

Arctic sea ice has declined about 34 percent since measurements were first made in the late 1970s. (ANI)