THE APPLICABILITY OF DUAL POLARIZED SENTINEL-1 SAR DATA FOR DETECTION OF FLOODED AREAS IN POL-E DOKHTAR, LORESTAN, IRAN
- Department of Surveying engineering, Faculty of civil engineering, Shahid Rajaee Teachers Training University, Tehran, Iran
Keywords: flood detection, dual polarized, sentinel-1, Pol-e-Dokhtar, incidence angles
Abstract. The main source for acquiring enough information about the areas of flood for the purpose of quick mapping is Microwave remote sensing because of its capability of imaging even in serious conditions of weather. Sentinel-1 with HV polarization is way more practical than VV polarization for detecting the flooded area due to its sensivity to short ripples over the surface of the flood. Despite this privilege, at low incidence angles, the same difficulty is observed in HV polarization. In this research, the main focus is on extracting the flood inundation with dual polarized sentinel-1 data in high and low incidence angles. The extraction of backscatter values for flood surface in VV and also HV polarizations had been done. The backscatter from floodwater is high at low incidence angles and sometimes low at high incidence angles as is illustrated by Sentinel-1 HV polarized data. However, the alteration is marginal at those high and low incidence angles with using Sentinel-1 VV polarized data. A measurement between Sentinel-1 VV & HV datasets and Optical Sentinel-2 had been done. The extension of flood is higher when we use Sentinel-2 as opposed to VV & HV and also the flood extent from VV at low incidence angles is way lesser. Another observation is that even at diverse incidence angles, the combination of flood mapping from VV & HV have the ability to compare with optical data much better.