ICESAT FULL WAVEFORM ALTIMETRY COMPARED TO AIRBORNE LASER ALTIMETRY OVER THE NETHERLANDS

Since 2003 the spaceborne laser altimetry system on board of NASA’s Ice, Cloud and land Elevation Satellite (ICESat) has acquired a large world-wide database of full waveform data organized in 15 products. In this research three products are evaluated over The Netherlands. For this purpose the raw full waveform product, the derived Gaussian decomposition product and the global land evalua-tion product are compared to laser data from the Dutch national airborne laser altimetry archive AHN. Using the CORINE land cover 2000 database allows us to compare ICESat to AHN elevation profiles with respect to the land cover classes forest, urban, bare land/low vegetation and water. This comparison shows that a large average height difference of 5.7 m occurs over forest, while much smaller differences of 1.24 m over urban areas, of 0.43 m over bare land/low vegetation and of 0.07 m over water are found. The reason for this large difference over forests is that the standard processing of NASA does not take the position of the last Gaussian mode of the waveform into account. Incorporating results from a full waveform processing procedure allows us to determine improved ICESat profiles. Comparing the improved profiles shows that the average difference with the AHN profiles over forest is reduced to-0.38 m, while the average differences for the other land cover classes do not exceed-0.75 m. Encountered limitations are discussed in the conclusions.