Spatiotemporal Analysis of Tropical Cyclone Landfalls in Northern Bay of Bengal, India and Bangladesh

Abstract

In the Northern Bay of Bengal (NBoB), cyclonic storms (wind speed: ≥34 knots) inflict considerable losses in coastal Bangladesh and India. By building a georeferenced panel database of storm landfalls for this region, one can obtain spatial information on period-wise strike intensities. In this study, 168 cyclone strike locations along a 1259-km impact zone were analyzed for seven historical periods between 1877 and 2016. Cyclone landfall trends for this region denote a gradual reduction in storm frequencies since peaking in 1961–1980, which is generally in line with already established trends for the Northern Indian Ocean and Bay of Bengal basins. One notable exception for the NBoB in this is the unimodal seasonality of storm landfalls during 1877–1960, but that also conformed to the bimodal regional trends in the later periods. Over time, the median location of storm strikes in the NBoB has shifted eastward into westernmost Bangladesh, with a particularly marked variability in location after 1960. Northern Odisha and West Bengal, India, experienced more cyclone strikes over the past 140 years; but the highest mean wind speeds occurred along Bangladesh’s eastern coast. Also, storm impacts have varied considerably within and across zones; northern Odisha and the Sundarban region of West Bengal have withstood the greatest impacts. The pronounced spatial and temporal variations in cyclone impacts evinced in this study can provide valuable information for relief prioritization and community adaptation to cyclones in the region. The general method developed for this analysis can be applied to other coastal locations for management of storm impacts.