STUDY ON ACCURACY ASSESSMENT OF DEM IN THE MARSH USING WITH INTERFEROMETRIC PALSAR, SENTINEL-1A AND TERRASAR-X IMAGES

To conserve and manage wetland resources, it is important to monitor hydro-geomorphic condition. In this paper, the interferometric SAR images of L-band ALOS-1 PALSAR, C-band Sentinel-1A and X-band TerraSAR were selected to produce DEM of wetland area in the Honghe National Nature Reserve using the InSAR technique. 111 testing points randomly selected from the 1:10000 topographic map were utilized to evaluate accuracy of remote-sensing based DEM. Finally, the interference coherence difference of wetland vegetation among three different wavelengths was compared and analyzed. The results showed that The DEM of wetland area produced by L-band ALOS-1 PALSAR interferometric images was in good agreement with the 1:10,000 topographic map data. The elevation value with the difference less than 3 meters account for over 76% of all testing points. The coherence coefficient of wetland calculated from PALSAR images was higher than Sentinel-1A and TerraSAR images. The coherence coefficient among wetland vegetation types was significantly different. The distribution area of forest and shrub-grass vegetation had a larger coherence coefficient than shallow-water marsh vegetation area and deep-water marsh vegetation area.