Deriving exclusion maps from C-band SAR time-series in support of floodwater mapping

REMOTE SENSING OF ENVIRONMENT

卷:265

Article

Zhao, Jie^1,2,3  Pelich, Ramona¹  Hostache, Renaud¹  Matgen, Patrick¹  Cao, Senmao⁴  Wagner, Wolfgang²  Chini, Marco¹ 

[1] Luxembourg Inst Sci & Technol, Dept Environm Res & Innovat, 5 Ave Hauts Fourneaux, L-4362 Esch Sur Alzette, Luxembourg

[2] Vienna Univ Technol, Dept Geodesy & Geoinformat, Res Grp Remote Sensing, A-1040 Vienna, Austria

[3] Vienna Univ Technol, Ctr Water Resource Syst, A-1040 Vienna, Austria

[4] EODC Earth Observat Data Ctr, A-1030 Vienna, Austria

关键词: Sentinel-1;    Flood risk management;    Time series analysis;    SAR;    EX-map (exclusion map);   

DOI  :  10.1016/j.rse.2021.112668

来源: Elsevier

【 摘 要 】

Synthetic Aperture Radar (SAR) intensity is used as an input to many flood-mapping algorithms. The appearance of floodwater tends to cause a substantial decrease of backscatter intensity over scarcely vegetated terrain. However, limitations exist in areas where the SAR backscatter is not sufficiently sensitive to surface changes, e.g. shadow areas due to topography or obstacles on the ground, densely forested areas, sand, etc. Thus, we argue that it is of paramount importance to complement any SAR-based flood extent map with an exclusion map (EXmap) indicating all areas where the presence of water cannot be derived from SAR intensity observations. In this study, we introduce a methodology for generating an EX-map based on the analysis of time-series of SAR backscatter data. In particular, the identification of the EX-map is based on the combined use of three temporal indicators based on backscatter statistics, i.e. temporal median, minimum and standard deviation. As a test case, EX-maps were derived from Sentinel-1 data acquired during the 2014-2019 time period from six representative study sites. Reference maps were generated using a global land cover map, Digital Elevation Model (DEM)derived shadow/layover masks, global urban footprint (GUF) data and a Sand Exclusion Layer (SEL). The crosscomparison revealed that the EX-map was consistent with reference maps obtained from other data sources.

【 授权许可】

Free