Interannual and Interdecadal Variations in Tropical Cyclone Activity over the Arabian Sea and the Impacts over Pakistan

Abstract

This study is to investigate the tropical cyclone (TC) activity over the Arabian Sea (AS). The idea of the topic rose from the work done by Chan (2005) on interannual and interdecadal variations of TC activity over the western North Pacific (WNP). In his study, Chan (2005) reviewed the Interannual and Interdecadal variations in tropical cyclone (TC) activity over the WNP and emphasized that the Interannual variations could largely be explained by changes in the planetary-scale flow patterns. Sea-surface temperatures (SSTs) in the WNP, however, did not contribute to such variations. Rather, SSTs in the central and eastern equatorial Pacific were significantly correlated with TC activity over the WNP. Changes in the SST in the equatorial Pacific were found to be in relation with the El Nino-Southern Oscillation (ENSO) phenomenon, and modifications of the planetary-scale flow associated with ENSO altered the conditions over the WNP and hence TC activity there.