Satellite data for mapping areal extent and changes of blue-ice areas in Antarctica

This paper reports results from a study where different satellite data sources have been used to map blue-ice areas and analyse changes over time. Two coastal areas of different character and one inland nunatak area with large blue-ice areas in East Antarctica are included in the study. Several different data sources are analysed in order to obtain as large data set as possible spanning from the early 1970’s to now. This includes use of Landsat MSS, TM and ERS SAR data. NOAA AVHRR data were used to get a regional overview and were also tested as an additional data source for one of the coastal areas. The blue-ice areas were mapped using grey level slicing in the near infrared band and in a ratio between visible and near infrared, which was found in a previous study to be a simple and powerful tool for enhancing blue-ice. The results from the change analysis show that there has been a decrease in areal extent of the blue-ice in the coastal areas, and a slight increase in the nunatak inland area.