Effect of the SRTM global DEM on the determination of a high-resolution geoid model: a case study in Iran
Speaker: Jen-Ru Liau
Abstract
Digital elevation models (DEMs) are used to get gravity anomalies and geoid models from observed gravity. So errors will be introduced in them by DEMs errors. The effects of DEMs errors are assessed by the evaluation of the absolute accuracy of nine DEMs in Iran area. The root mean square (rms) of those data is using to find the best–possible. The high resolution Shuttle Radar Topography Mission (SRTM) DEM with the minimum error is used in gravity anomalies and geoid models. The absolute vertical accuracy of the SRTM in Iran is 6.5 meter. The accuracy of the SRTM DEM is comparable with the high-precision photogrammetry-based DEM of Iran. Very large differences between the GLOBE and SRTM DEMs are the range of -750 m to 550 m. For surface gravity anomaly, it will make an error on the range of -140 mGal to 140 mGal. In addition, it will make an error on the range of -60 mGal to 60 mGal, for simple planar Bouguer anomaly correction terms. In geoid heights, they are also different in the range of -1.1 m to 1 m.
Reference
Kiamehr, R., & Sjoberg, L. E. (2001). Effect of the SRTM global DEM on the determination of a high-resolution geoid model: a case study in Iran, J. Geodesy, 79(9), 540-551.
Li, X., & Gotzez, H.-J. (2001). Tutorial: Ellipsoid, geoid, gravity, geodesy, and geophysics, Geophysics, 66(6), 1660-1668.
Merry, C. L. (2003). DEM-induced errors in developing a quasi-geoid model for Africa, J. Geodesy, 77(9), 537-542.