APPLICATION OF RADAR ALTIMETRY TO ESTIMATE SEA ICE EXTENT AND THICKNESS EAST OF GREENLAND

摘要

This study investigates the use of space borne radar altimetry to estimate sea ice extent and sea ice thickness in the sea East of Greenland. In Fig. 1 and Fig. 2 the East part of Greenland and the four tracks analysed are shown. The data analysed are ENVISAT radar altimeter (RA-2) data, which are compared with QuikSCAT scatterometry data. In order to investigate sea ice extent, the shapes of the waveform are studied as they are an indicator of the surface properties depending from the surface roughness. Two quantities are extracted from the shape of the waveforms in order to analyze sea ice conditions: backscatter coefficient and pulse peakiness parameter (PP). The former is extracted from both ENVISAT and QuikSCAT satellites, and compared one another; the latter is extracted from ENVISAT data and used to discriminate the specular waveforms from the diffuse. This is used to estimate sea ice thickness. The data used in this analysis spans a whole year: from 15th March 2004 until 4th April 2005. Four repeated tracks (sampling period 35 days) are analyzed over the eastern Greenland sea in order to point out changes in the data originating from the sea ice changes over the seasons, e.g. accumulation of snow, and meltwater.