Tropical Cyclone - Ocean Interactions | Christina M Patricola-DiRosario

Tropical Cyclone - Ocean Coupling in Global Climate Models

SST cold wake produced by Hurricane Irma, as shown by observed SST (ºC) from Sep 10, 2017 minus Sep 5, 2017.

This study aims to quantify the impacts of atmosphere–ocean coupling on simulated and projected tropical cyclone (TC) precipitation globally. We used global climate model (GCM) simulations over 1950–2050 from the High Resolution Model Intercomparison Project (HighResMIP) and compared its fully coupled atmosphere–ocean GCMs (AOGCMs) with atmosphere-only GCMs (AGCMs). We find that ocean coupling generally leads to decreased TC precipitation over ocean and land. Large-scale sea surface temperature (SST) biases are critical drivers of the precipitation difference, with secondary contributions from local TC–ocean feedbacks via SST cold wakes. The AOGCMs and AGCMs consistently project TC precipitation increases in 2015–2050 relative to 1950–2014 over ocean for all basins, and for landfalling TCs in the North Atlantic and western North Pacific.

Huang, H., Patricola, C. M., & Collins, W. D. (2021). The Influence of Ocean Coupling on Simulated and Projected Tropical Cyclone Precipitation in the HighResMIP-PRIMAVERA Simulations, Geophysical Research Letters, 48(20), e2021GL094801.

_{This research was supported by the U.S. Department of Energy Office of Science (BER RGMA program) under Early Career Research Program Award Number DESC0021109 and under DE-AC02-05CH11231. High-performance computing resources provided by the National Energy Research Scientific Computing Center (NERSC).}

Air-sea Coupling Influence on Projected Changes in Tropical Cyclone Events

Tropical cyclone (TC) projections with atmosphere-only models are associated with uncertainties due to their inability to represent TC-ocean interactions. However, global coupled models, which represent TC-ocean interactions, can produce basin-scale sea surface temperature biases in seasonal to centennial simulations that lead to challenges in representing TC activity. Therefore, focusing on recent individual major hurricane events, we investigated the influence of TC-ocean coupling on the response of TCs to anthropogenic change using atmosphere-only and coupled atmosphere-ocean regional model simulations. Under an extremely warm scenario, coupling does not influence the signs of projected TC rainfall and intensity responses. Coupling, however, does influence the magnitude of projected intensity and especially rainfall. Within a 500 km radius region of the TCs, the projected rainfall increases in coupled simulations are 3–59 % less than in the atmosphere-only simulations, driven by enhanced TC-induced sea surface temperature cooling in the former.

Danso, D. K., Patricola, C. M., Kurian, J., Chang, P., Klotzbach, P., & Lin, I-I. (2024). Air-sea Coupling Influence on Projected Changes in Tropical Cyclone Events. Weather and Climate Extremes, 43, 100649.

_{updated 3/13/2024}