North Indian Ocean tropical cyclone activities inf

Authors: JunPeng Yuan Jie Cao

Publish Date: 2012/12/11

Volume: 56, Issue: 5, Pages: 855-865

PDF Link

Abstract

Using Joint Typhoon Warning Center tropical cyclone TC track data over the North Indian Ocean NIO National Centers for Environmental Prediction monthly reanalysis wind and outgoing longwave radiation data and National Oceanic and Atmospheric Administration sea surface temperature data from 1981 to 2010 spatiotemporal distributions of NIO TC activity and relationships with local sea surface temperature SST were studied with statistical diagnosis methods Results of empirical orthogonal function EOF analysis of NIO TC occurrence frequency show that the EOF1 mode which accounts for 16 of total variance consistently represents variations of TC occurrence frequency over the whole NIO basin However spatial distributions of EOF1 mode are not uniform mainly indicating variations of westwardmoving TCs in the Bay of Bengal The prevailing TC activity variation mode oscillates significantly on a quasi5 year interannual time scale NIO TC activity is notably influenced by the Indian Ocean dipole IOD mode When the Indian Ocean is in a positive negative phase of the IOD NIO SST anomalies are warm in the west east and cold in the east west which can weaken strengthen convection over the Bay of Bengal and eastern Arabian Sea and cause anticyclonic cyclonic atmospheric circulation anomalies at low levels This results in less more TC genesis and reduced increased opportunities for TC occurrence in the NIO In addition positive negative IOD events may strengthen weaken westerly steering flow over the Bay of Bengal which further leads to fewer more westwardmoving TCs which appear in regions west of 90°E in that bay

Keywords: