Error Discovered in Antarctic Sea-ice Record

Error Discovered in Antarctic Sea-ice Record

Antarctic sea ice peaks in September, and reaches a minimum in February. In some places, sea ice melts completely in the summer. (NASA maps by Jesse Allen, based on AMSR-E data from the National Snow and Ice Data Center.)

Antarctic sea ice peaks in September, and reaches a minimum in February. In some places, sea ice melts completely in the summer. (NASA maps by Jesse Allen, based on AMSR-E data from the National Snow and Ice Data Center.)

Rising temperatures have caused the amount of Arctic sea ice to shrink dramatically since global observations began in the 1970s. But on the other side of the world, sea ice in Antarctica was at first steady — and then began to slowly expand in the mid-2000s.

Some researchers now say that the Antarctic trend may have been inflated by an error in the decades-long record of satellite observations of Southern Hemisphere sea ice. Scientists process data from microwave-sensing satellites using one of two standard algorithms to distinguish bright sea ice from dark open water.

Researchers led by Ian Eisenman, a climatologist at the Scripps Institution of Oceanography in San Diego, California, discovered a mismatch between an older and a newer version of the same NASA sea-ice data set that occurred when a satellite sensor was replaced in December 1991. Such “jumps” in data are caused by slight differences in the satellites’ sensitivity, and are usually corrected when scientists process the data collected by the probes.

But the error that Eisenman identified – reported in the 22 July issue of The Cryosphere – wasn’t obvious. He found it only by comparing an old version of the data set with a 2008 version, and says that the data were too noisy to tell which version had been mishandled.

Read  the original paper in The Cryosphere.

 

 

Source: The Scientific Committee on Antarctic Research (SCAR)

Categories: Remote Sensing

About Author

GIS Resources

GIS Resources is an initiative of Spatial Media and Services Enterprises with the purpose that everyone can enrich their knowledge and develop competitiveness. GIS Resources is a global platform, for latest and high-quality information source for the geospatial industry, brings you the latest insights into the developments in geospatial science and technology.

Write a Comment

Your e-mail address will not be published.
Required fields are marked*

This site uses Akismet to reduce spam. Learn how your comment data is processed.