Assessment of Tropical Cyclone Remal Induced Inundation in Patuakhali and Barguna Districts of Bangladesh Using Sentinel Satellite Images

Abstract

Tropical cyclones are common natural phenomena that affect both natural and human environment. They often cause significant flood inundation in coastal regions.  Tropical Cyclone Remal, which struck the southern coast of Bangladesh in May 2024, caused significant flooding and damage across multiple districts of the country. This study aims to assess the inundation caused by Tropical Cyclone Remal in the central coastal districts of Patuakhali and Barguna of Bangladesh using both Sentinel-1 SAR and Sentinel-2 data. Additionally, it identifies the land use and land cover (LULC) classes affected by the inundation.  To find the extend of inundation, Sentinel-1 SAR data was processed using binarization techniques on images taken pre- and post-cyclone. On the other hand, Sentinel-2 optical imagery was used to map the different LULC classes in the study area. By overlaying the LULC and inundation maps, the study calculated the LULC classes affected by the inundation. Sentinel data were useful in the whole process especially sentinel-1 for its capacity of penetration though cloud. The results of this study highlight the significant impact of Cyclone Remal on the central coastal districts of Patuakhali and Barguna in Bangladesh. Patuakhali is the most affected district in terms of total area (835 sq. km) inundated whereas in terms of severity of inundation, Barguna affected severely. Most of these inundated areas were agricultural lands. The cyclone hit during the harvesting time of kharif-1 crops and the crops were damaged by prolonged inundation of the agricultural lands. This study will be helpful to the policy makers in case of informing about the severity of tropical cyclones in coastal districts of Bangladesh especially Patuakhali and Barguna district.

The Dhaka University Journal of Earth and Environmental Sciences, Vol. 14(1), 2025, P 1-17