The Study Of Ice Sheet Height Change In Antarctic By Using ICESat Laser Altimeter Data

The melting of polar ice sheet is one of the main dynamic factors which affect on the global climate, contribute to global sea-level rise, and directly threats the survival environment of the mankind. The ICESat saltellite launched on January 13, 2003 by NASA provides valuable measurements for studying the ice sheet topography and the ice sheet height changes in Antarctica.The methods for estimating height change of polar ice sheet by using ICESat laser altimeter data are described in this paper, and the result from ICESat is compared to that from GRACE.1. The GLAS waveform processing is studied by simulating single and multiple peaks.The waveforms can be recovered. The processing of waveforms is also verified by simulating waveforms with noise.2. The elevations on land laser altimeter from ICESat are compared with that from static GPS observations and RTK GPS observations. A minimum height difference of 0.103m was found between GPS and ICESAT in a mountainous area.3. The DEM over the Antarctic ice sheet is derived from ICESat laser altimeter data from 2002.02 to 2008.02 and compared with the existing DEMs.4. The height changes in Antarctic ice sheet are obtained using crossover analysis. From the result, one can see clearly that the heights decrease in west antarctice, while the obvious mass deficit is also shown from the earth's gravity field models derived by GRACE.5. A linear trend and a periodic signal are determined using collinear analysis in four areas in Antarctic. The trend is comparable with that from GRACE, especially in Antarctic Peninsula, west antarctice and east antarctice, etc.