Downscaled Tropical Cyclones in Simulations of the Last Glacial Maximum

Abstract

A prominent area of current study is how tropical cyclone (TC) behavior will respond to future changes in global climate. One way to complement this research is by analyzing TC characteristics in simulations of past climates. In this project, we analyze the properties of TCs statistically downscaled from several climate simulations using the Coupled Hurricane Intensity Prediction System (CHIPS). This is done utilizing climate simulations of the Last Glacial Maximum (LGM) and 20th Century from three members of the Paleoclimate Modelling Intercomparision Project Phase III (PMIP3). We compare changes in large-scale tropical cyclone genesis factors to that of atmospheric circulations to better understand underlying sources of inter-model variability. Results from all three models depict a higher proportion of TCs reaching high (Category 4 and 5) intensities in the 20th Century climate compared to the colder LGM climate. Changes in TC annual frequency are more variable, with two models producing increased annual frequency with LGM to 20th Century warming and one model producing the opposite. This analysis provides insight on how tropical cyclones may have behaved during the LGM and can be compared to future projections of TC response to anthropogenic climate change.