Research questions satellite data over Antarctic sea expansion
Posted on Jul 23 2014 | IANS
Washington, July 23 : The Antarctic sea ice may not be expanding as fast as previously thought, a new research suggests, adding that there may be a processing error in the satellite data.
Arctic sea ice is retreating at a dramatic rate. In contrast, satellite observations suggest that sea ice cover in the Antarctic is expanding and that sea ice extent has reached record highs in recent years.
Now, a team of researchers has suggested that much of the measured expansion of the Southern Hemisphere sea ice cover may be due to an error, not previously documented, in the way satellite data was processed.
"This implies that the Antarctic sea ice trends reported in the Intergovernmental Panel on Climate Change (IPCC) 2007 and 2013 reports cannot both be correct: our findings show that the data used in one of the reports contains a significant error," said lead author Ian Eisenman of the Scripps Institution of Oceanography at University of California San Diego.
But we have not yet been able to identify which one contains the error, he added.
Reflecting the scientific literature at the time, the 2007 IPCC report said that Antarctic sea ice cover remained more or less constant between 1979 and 2005.
On the other hand, recent literature and the 2013 IPCC report indicate that, between 1979 and 2012, Southern Hemisphere sea ice extent increased at a rate of about 16.5 thousand square km per year.
Scientists assumed the difference to be a result of adding several more years to the observational record.
"But when we looked at how the numbers reported for the trend had changed, and we looked at the time series of Antarctic sea ice extent, it did not look right," Eisenman noted.
Scientists have used satellite data to measure sea ice cover for 35 years.
If the error is in the current dataset, the results could contribute to an unexpected resolution for the Antarctic sea ice cover enigma, said the findings published in The Cryosphere, a journal of the European Geosciences Union (EGU).