Assessing Coastal Inundation due to a Transboundary Cyclone Using Sentinel 1 SAR Imagery

Cyclone Amphan made landfall on the Indian state of West Bengal on May 20, 2020, during the initial phase of the COVID-19 pandemic. It passed through the western edge of the Sundarbans mangrove forest following a north-north-eastern track affecting neighboring Bangladesh as well. The overlapping of this cyclone during the pandemic made emergency response especially challenging for two of the most densely populated countries in the world. Nevertheless, remote sensing has been extremely useful in such scenarios where accessibility and in situ data-sharing are compromised. The application of multispectral satellite imagery is especially common in large-scale impact assessment following natural events, but the presence of clouds during cyclones makes these images often less effective. Sentinel 1 synthetic-aperture radar (SAR) imagery thus can be very useful due to its cloud penetration capability. This study shows that this freely available global data can provide back-of-the-envelope damage assessment using minimal computational facilities. Therefore, the objective is to perform an inundation assessment in coastal districts (level-2 administrative area) of India and Bangladesh due to Cyclone Amphan using Sentinel 1 SAR imagery. © ASCE.