An algorithm for slope estimation from repeat tracks of ICESat/GLAS

A slope estimation model and algorithms were advanced based on the repeat ground track elevation data collected from the Geoscience Laser Altimeter System (GLAS) on board the Ice, Cloud and land Elevation Satellite (ICESat). Innovative algorithm steps show and confirm the reference starting point (RSF) on the reference track (RT) and the corresponding starting point (CSF) on other repeat corresponding track (CT). The slope model and algorithms were validated with the elevation data from ground track 420 collected by ICESat/GLAS when passing over the Beijing area during 2003-2009. The RMS and standard deviation of slope differences between RT and CTs were deduced and discussed. The results show that the RMS and standard deviation (STD) of the slope differences increase with the increase in the STD/RMS of the separation between the CT and RT. The slope drawing on a geographic map were coincidental with the geographical ground truth when compared with an image obtained from Google map. The calculated slope based on ICESat/GLAS data was compared to that based on SRTM DEM data demonstrating the reliability of these results.