ASTER GDEM validation using LiDAR data over coastal regions of Greenland

Abstract

Elevation data from airborne Light Detection and Ranging (LiDAR) campaigns are used in an attempt to evaluate the accuracy of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) global digital elevation model (GDEM) in Greenland. The LiDAR elevation data set is characterized by a high spatial resolution of about 1 m and elevation accuracy of 20–30 cm root mean square error (RMSE). The LiDAR data sets used were acquired during ice-monitoring campaigns carried out from 2003 to 2008. The study areas include ice-free regions, local ice caps and the ice sheet margin. A linear error of 15–65 m was derived, which is far greater than the 20-m product specification. This estimation is biased by both the seasonal and the climatic changes in local ice caps because the ASTER GDEM was computed from imagery acquired in the period 2000–2009. High sloping areas along the coastal regions of Greenland and the effect of the number of scenes used to generate the ASTER GDEM as well as relief are associated with the GDEM accuracy.