UtilizingtheJointTyphoonWarningCenter(JTWC)andTokyo-TyphoonCenteroftheJapanMeteorologicalAgency(JMARSMCTOKYO)best-tracktropicalcyclone(TC)datafortheperiod1951-2014,variationsinspatialandtemporalcharacteristicsofNorthwestPacificTCactivityforaglobalwarmingscenarioarediscussed.Theresultssuggestthatsincetheearly1960s,therehasbeenanoveralldecreasingtrendinthefrequencyofoccurrence,intensity,peakintensity,lengthofmovement,andlifetimeofTCs.However,globalwanninghasledtoalinearlyincreasingtrendinTCactivityineasternAsia,whichindicatesthatNorthwestPacificTCactivitydecreases,butthefrequencyoflandfallsandintensityarelikelystrengthened.Therefore,thethreatofTCstowardseasternAsiaisenhanced.TheincreaseinTCactivityineasternAsiaislikelytheresultofastrengthenedWalkercirculationduetoanincreasingtemperaturegradientbetweenthenorthwestPacificOceanandthecentralandeasternPacificOcean.ThestrengtheningWalkercirculationcouldincreasethemagnitudeoftheverticalwindshear,relativevorticity,andmeridionalwindshearoflow-leveleasterliesneartheequatorinthetropicalNorthwestPacific,whichaffectsthespatialandtemporalvariationsofTCactivityintheNorthwestPacific.
