Western North Pacific Tropical Cyclone Model Tracks in Present and Future Climates

Abstract

Western North Pacific tropical cyclone (TC) model tracks are analyzed in two large multimodelensembles, spanning a large variety of models and multiple future climate scenarios. Two methodologiesare used to synthesize the properties of TC tracks in this large data set: cluster analysis and mass momentellipses. First, the models’ TC tracks are compared to observed TC tracks’ characteristics, and a subset ofthe models is chosen for analysis, based on the tracks’ similarity to observations and sample size. Potentialchanges in track types in a warming climate are identified by comparing the kernel smoothed probabilitydistributions of various track variables in historical and future scenarios using a Kolmogorov-Smirnovsignificance test. Two track changes are identified. The first is a statistically significant increase in thenorth-south expansion, which can also be viewed as a poleward shift, as TC tracks are prevented fromexpanding equatorward due to the weak Coriolis force near the equator. The second change is an eastwardshift in the storm tracks that occur near the central Pacific in one of the multimodel ensembles, indicatinga possible increase in the occurrence of storms near Hawaii in a warming climate. The dependence of theresults on which model and future scenario are considered emphasizes the necessity of including multiplemodels and scenarios when considering future changes in TC characteristics.