Surface melting derived from microwave radiometers: a climatic indicator in Antarctica

This paper aims at presenting a new dataset including the melt events derived from microwave remote sensing occurring in Antarctica from summer 1979/80 to 2005/06. The method for detecting melt events and sources of error is presented, and then trends in melt duration for every pixel are extracted from the dataset, mapped and analyzed. The analysis focuses on two particular cases, and the main results show that: (1) the trends over the period 1980-2006 in the Antarctic Peninsula match with lengthening of the melt season on the ice shelves and, surprisingly, shortening of the melt season in the mountainous area of the peninsula; and (2) the trends over the period 1996-2006 on the entire continent show a dipolar pattern, with the western regions experiencing decreasing melt duration, whereas East Antarctica and the Ross Ice Shelf experience increasing melt duration. This pattern closely mirrors the temperature pattern expected when the Southern Annular Mode is in a decreasing trend, as it is over the period 1996-2006. For further analysis and validation, the dataset has been made available at http://www-igge.obs.ujf-grenoble.fr/similar to picard/melting/.