Impact Assessment of Tropical Cyclones Amphan and Nisarga in 2020 in the Northern Indian Ocean

Abstract

The Northern Indian Ocean (NIO) is one of the most vulnerable coasts to tropical cyclones (TCs) and is frequently threatened by global climate change. In the year 2020, two severe cyclones formed in the NIO and devastated the Indian subcontinent. Super cyclone Amphan, which formed in the Bay of Bengal (BOB) on 15 May 2020, made landfall along the West Bengal coast with a wind speed of above 85 knots (155 km/h). The severe cyclone Nisarga formed in the Arabian Sea (ARS) on 1 June 2020 and made landfall along the Maharashtra coast with a wind speed above 60 knots (115 km/h). The present study has characterized both TCs by employing past cyclonic events (1982–2020), satellite-derived sea surface temperature (SST), wind speed and direction, rainfall dataset, and regional elevation. Long-term cyclonic occurrences revealed that the Bay of Bengal encountered a higher number of cyclones each year than the ARS. Both cyclones had different intensities when making landfall; however, the regional elevation played a significant role in controlling the cyclonic wind and associated hazards. The mountain topography on the east coast weakened the wind, while the deltas on the west coast had no control over the wind. Nisarga weakened to 30 knots (56 km/h) within 6 h from making landfall, while Amphan took 24 h to weaken to 30 knots (56 km/h). We analyzed precipitation patterns during the cyclones and concluded that Amphan had much more (1563 mm) precipitation than Nisarga (684 mm). Furthermore, the impact on land use land cover (LULC) was examined in relation to the wind field. The Amphan wind field damaged 363,837 km2 of land, whereas the Nisarga wind field affected 167,230 km2 of land. This research can aid in the development of effective preparedness strategies for disaster risk reduction during cyclone impacts along the coast of India.

Multi-Criterion Analysis of Cyclone Risk along the Coast of Tamil Nadu, India—A Geospatial Approach

“…The Bay of Bengal is more prone to cyclones and depressions than the Arabian Sea and is frequently affected. Gujarat is the most vulnerable state to tropical cyclones originating in the Arabian Sea [90]. Deadly cyclones like Severe Cyclonic Storms mainly originate in the Bay of Bengal due to warm air.…”

Characterization of the Coastal Vulnerability in Different Geological Settings: A Comparative Study on Kerala and Tamil Nadu Coasts Using FuzzyAHP

“…The erosion of coasts, rise in mean sea level, and increased storminess of the ocean waters enhance coastal processes that lead to ecological changes along the coasts [12]. These enhanced coastal processes produce a list of coastal changes, including shore erosion, strong storm surges, an increase in significant wave height, an increase in sea level rise, and cyclonic activity, impacting the coast both geographically and economically [3,13,14]. Coastal systems are increasingly threatened by the potential impacts of climate change, according to a series of assessments by the Intergovernmental Panel on Climate Change (IPCC).…”