Tropical Cyclone Response to Vertical Wind Shear in High-Resolution Climate Model Ensembles, 9/11/25 скачать в хорошем качестве

Tropical Cyclone Response to Vertical Wind Shear in High-Resolution Climate Model Ensembles, 9/11/25

Tropical Cyclone Response to Vertical WindShear in High-Resolution Climate Model Ensembles Dr. Jacob Carstens University of North Dakota ABSTRACT: Mean tropical cyclone (TC) intensity is generally projected to increase as oceans warm, along with the proportion of TCs that become particularly intense. However, most TCs fail to reach their maximum potential intensity due to various environmental factors. In particular, vertical wind shear (VWS) has long been considered an important negative influence on TC development via vortex tilt, asymmetries in kinematic and thermodynamic structure, and ventilation of cooler, drier environmental air into the circulation. Recent work has shown that uncertain projections of future VWS are a leading-order cause of spread in projected TC activity among climate models. Process-level understanding of this relationship is limited, however. For example, parameters derived from the large-scale state (e.g., genesis potential indices) may not accurately project TC behavior in the future climate. Additionally, TC-environment interactions are typically estimated using monthly mean quantities (e.g., VWS, large-scale absolute vorticity) that may not represent the synoptic- and mesoscale environments that TCs and their precursor seeds encounter in reality. Our group is developing the first comprehensive assessment of how TCs respond to their unique environmental VWS in climate models. We first analyze the TC-VWS interaction in 14 simulations from the HighResMIP ensemble within CMIP6, forced by observed historical sea surface temperatures. We evaluate the global climatology of the VWS imparted on TCs, the relationship between VWS magnitude and subsequent intensity change, and the structural response of the TCs when encountering VWS, compared to a 17-year compilation of TCs in observations and reanalysis. In particular, HighResMIP helps us isolate the role of model resolution in capturing the TC-VWS relationship, as the 14 simulations we analyze come from 6 modeling centers, each of which run multiple simulations with similar physics, but on different grids. I conclude by introducing emerging projects, including analyzing TCs in the MESACLIP climate model ensemble, using dropsonde and satellite observations to diagnose radiation feedbacks on TCs, and evaluating tornadic convective environments in TC rainbands prior to landfall.