Geo-ecological, shoreline dynamic, and flooding impacts of Cyclonic Storm Mocha: A geospatial analysis

Manoranjan Mishra; Rajkumar Guria; Suman Paul; Biswaranjan Baraj; Celso Augusto Guimarães Santos; Carlos Antonio Costa Dos Santos; Richarde Marques da Silva

doi:10.1016/j.scitotenv.2024.170230

Geo-ecological, shoreline dynamic, and flooding impacts of Cyclonic Storm Mocha: A geospatial analysis

Sci Total Environ. 2024 Mar 20:917:170230. doi: 10.1016/j.scitotenv.2024.170230. Epub 2024 Jan 24.

Authors

Manoranjan Mishra¹, Rajkumar Guria², Suman Paul², Biswaranjan Baraj², Celso Augusto Guimarães Santos³, Carlos Antonio Costa Dos Santos⁴, Richarde Marques da Silva⁵

Affiliations

¹ Department of Geography, Fakir Mohan University, Vyasa Vihar, Nuapadhi, Balasore 756089, Odisha, India. Electronic address: geo.manu05@gmail.com.
² Department of Geography, Fakir Mohan University, Vyasa Vihar, Nuapadhi, Balasore 756089, Odisha, India.
³ Department of Civil and Environmental Engineering, Federal University of Paraíba, João Pessoa 58051-900, Paraíba, Brazil. Electronic address: celso@ct.ufpb.br.
⁴ Academic Unity of Atmospheric Sciences, Federal University of Campina Grande, Campina Grande 58109-970, Paraíba, Brazil.
⁵ Department of Geosciences, Federal University of Paraíba, João Pessoa 58051-900, Paraíba, Brazil.

PMID: 38278234
DOI: 10.1016/j.scitotenv.2024.170230

Abstract

This research comprehensively assesses the aftermath of Cyclonic Storm Mocha, focusing on the coastal zones of Rakhine State and the Chittagong Division, spanning Myanmar and Bangladesh. The investigation emphasizes the impacts on coastal ecology, shoreline dynamics, flooding patterns, and meteorological variations. Employed were multiple vegetation indices-Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Modified Vegetation Condition Index (mVCI), Disaster Vegetation Damage Index (DVDI), and Fractional Vegetation Cover (FVC)-to evaluate ecological consequences. The Digital Shoreline Assessment System (DSAS) aided in determining shoreline alterations pre- and post-cyclone. Soil exposure and flood extents were scrutinized using the Bare Soil Index (BSI) and Modified Normalized Difference Water Index (MNDWI), respectively. Additionally, the study encompassed an analysis of microclimatic variables, comparing meteorological data across pre- and post-cyclone periods. Findings indicate significant ecological impacts: an estimated 8985.46 km² of dense vegetation (NDVI >0.6) was adversely affected. Post-cyclone, there was a discernible reduction in EVI values. The mean mVCI shifted negatively from -0.18 to -0.33, and the mean FVC decreased from 0.39 to 0.33. The DVDI underscored considerable vegetation damage in various areas, underscoring the cyclone's extensive impact. Meteorological analysis revealed a 245 % increase in rainfall (20.22 mm on May 14, 2023 compared to the May average of 5.86 mm), and significant increases in relative humidity (14 %) and wind speed (205 %). Erosion was observed along 74.60 % of the studied shoreline. These insights are pivotal for developing comprehensive strategies aimed at the rehabilitation and conservation of critical coastal ecosystems. They provide vital data for emergency response initiatives and offer resources for entities engaged in enhancing coastal resilience and protecting local community livelihoods.

Keywords: Climatic extremities; Coastline alterations; Natural hazards; Net Shoreline Movement; Tropical cyclone; Vegetation damage.