AGS-PRF: Examining the Response of Tropical Cyclone Precipitation Structure to Climate Change Using Idealized and Realistic Models

Stansfield, Alyssa M, Stony Brook NY

Investigators

Abstract

Tropical cyclones (TCs) are weather systems made up of rotating thunderstorms that usually form in the tropics and that can cause injuries, fatalities, and expensive property damage when they move over land. While coastal residents are often most concerned about flooding from TC landfalls, TC precipitation and associated flooding can extend hundreds of miles inland. Although it is well-established that TC precipitation rates are expected to increase in the future due to climate change, the scientific community is less certain about how the patterns of TC precipitation may change, which has implications for issuing the most accurate flood warnings and evacuation mandates ahead of TC landfalls. This project will explore how TC precipitation structure will be impacted by climate change since structural changes may shift the distribution of precipitation within TCs, which could impact flooding patterns. TC precipitation comes from both the inner core, commonly known as the eye wall, and outer rainbands. A more complete understanding of how TC precipitation in the inner core and outer rainband regions is related and how precipitation may change in these two regions because of climate change can aid TC forecast modelers in adapting their models to the changing climate, which will in turn help emergency managers and decision makers save lives in areas prone to TC landfalls. Previous modeling studies on TC precipitation and climate change have used coarse-resolution models that cannot resolve TC precipitation structures. Recent observational studies using about 20 years of satellite data found a decreasing trend in TC inner core precipitation and an increasing trend in TC outer rainband precipitation, while models using grid spacings of tens of kilometers or coarser have projected conflicting changes in inner core versus outer rainband precipitation increases due to climate change. This research will use an idealized high-resolution model with explicitly-resolved convection to increase the understanding of how three-dimensional precipitation structures within TCs are impacted by atmospheric and sea surface temperature warming. Results will provide insight into discrepancies between observed trends and climate model predictions of changes in TC precipitation structure. Physical mechanisms behind any notable changes in precipitation structure will be explored. Beyond the idealized simulations, an analysis of pseudo-global warming simulations run at the same resolution as the idealized simulations will show if the results discovered with the idealized simulations apply to TCs in more Earth-like environments and how precipitation during TC landfalls may change in the future. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.