Downscaled Tropical Cyclones in Paleoclimate Simulations: Intermodel Variability

A prominent area of current study is how trends in tropical cyclone tracks, intensity, longevity, and annual cycle will respond to changes in global climate. One way to complement studies of the response of tropical cyclones to anthropogenic climate change is to study their behavior in simulations of past climates, which include substantially larger departures from modern conditions. Here we analyze storms downscaled from simulations of the Last Glacial Maximum (LGM), and Mid-Holocene (MH). The Coupled Hurricane Intensity Prediction System (CHIPS) is used to simulate tropical cyclones utilizing data from four members of the Paleoclimate Modelling Intercomparision Project Phase III (PMIP3). Output from simulations depict a lower number of tropical cyclones in most models’ representation of both the LGM and Mid-Holocene compared to the preindustrial and 20^th century controls, but individual members produce more. This variability in downscaled tropical cyclones is analyzed across climate states and compared to large-scale environmental factors. Various spatial and statistical methods are used to quantify the impact of static and changing environmental factors on patterns in downscaled storm characteristics. Spatial distributions of downscaled tropical cyclones are also compared to commonly used tropical cyclone proxies. This analysis provides insight on how tropical cyclones may have behaved during the LGM and Mid-Holocene. These results and methods, in conjunction with other studies, can be applied to projections of the response of tropical cyclones to anthropogenic climate change.