Global sea ice monitoring from microwave satellites

The global sea ice covers can be regularly and frequently monitored using satellite passive microwave sensors. Recent studies using passive microwave data have detected significant decreases in Arctic ice extent and ice area, with no significant changes in the Antarctic. The authors analyze microwave data through mid-1995, to identify changes in ice extent, ice area, and, for the first time, overall ice concentration. The authors find continued decreases in the Arctic ice extent and ice area, and establish a decrease in the ice concentration. They also include a seasonal analysis of the Arctic trends, which establishes the greatest decreases to be in summer and spring. The relatively large summer decreases imply a reduction in the multi-year ice area, suggesting reduced ice thickness, though observational data are lacking.