Long melt seasons on ice shelves of the Antarctic Peninsula: An analysis using satellite-based microwave emission measurements

Abstract

We have examined the record of melt-season duration on the Antarctic Peninsula using two techniques for detecting the presence of a melt signal in microwave-emission time series covering the period 1978-2000. We have obtained similar estimates of melt-season length using the cross-polarized gradient ratio (XPGR) technique and calibrations previously applied in Greenland and a technique which detects the jump in emission caused by melt without using a sensor-and frequency-dependent threshold value. The close correspondence between results from the two techniques on peninsula ice shelves suggests that the XPGR analysis can be used over the length of the time series. The results show that the long melt seasons of 1992/93 and several later years were exceptional occurrences on the northern parts of the Larsen Ice Shelf. These melt seasons were followed by disintegration events, supporting a possible cause-and-effect relationship.