Contrasting two spring SST predictors for the number of western North Pacific tropical cyclones

Abstract

AbstractRecent studies have revealed that two boreal spring sea surface temperature (SST) indices have potential to predict the number of western North Pacific (WNP) tropical cyclones (TCs) in the following peak typhoon season (June–October): the northern tropical Atlantic (NTA) SST, and the SST gradient (SSTG) between the southwestern Pacific and western Pacific warm pool. The interannual and interdecadal variations of NTA SST and SSTG and their relationships to the number of WNP TCs during 1950–2013 were compared. On the interdecadal timescale, SSTG showed better correlation with the number of WNP TCs than NTA SST. The interdecadal variation of NTA SST was closely associated with the Atlantic Multidecadal Oscillation, while that of SSTG was anti-correlated with the Central Pacific (CP) El Nino index at the interdecadal timescale. On the interannual timescale, both NTA SST and SSTG were modulated by two types of El Nino. The NTA SST revealed significant correlations with the number of WNP TCs beginning f...