Non-Stationary Variation of Tropical Cyclones Activities in the Northwest Pacific

(整期优先)网络出版时间:2010-04-14
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Basedontheanalysisoftropicalcyclone(TC)databaseintheNorthwestPacific(NWP)from1945to2008,wenotonlyextractthetemporalvariationofTCintensityandfrequency,butalsogivetheirspatialdistributionbothintheNWPandintheSouthChinaSea(SCS).TheresultsshowthatthereisanobservationalincreaseofTCactivities,whichmanifestsastheenhancementofthepowerdissipationindex(PDI)andthegrowthofTCfrequency,especiallyfortyphoonsandstrongtyphoons.TheinhomogeneousspatialdistributionsofTCfrequencyandintensityarealsoprovidedbothintheNWPandintheSCS.Forexample,theregionofZhongshaIslandsandDongshaIslandsintheSCS(15°~22°N,115°~120°E),westtothePhilippineIslandsistheplacewithfrequentoccurrenceofstrongtyphoons,amongwhichthewindspeedof7TCsin64yearsexceeds60m/s.