Improving Simulations of Daily Mean Dynamic Sea Level Extremes in the Gulf of Mexico with High-Resolution Community Earth System Model

Extreme sea-level events, such as those caused by tropical cyclones (TCs), pose significant risks to coastal areas. However, the current generation of climate models struggles to simulate these events due to coarse resolution. By comparing high-resolution (HR) and low-resolution (LR) Community Earth System Model (CESM) simulations with tide gauge and altimeter data along the U.S. Gulf of Mexico (GoM) coast, we find that HR better represents both mean dynamic sea level (DSL) and daily mean extreme DSL (EDSL) statistics. In contrast, LR significantly underestimates the strength of EDSL mainly due to its deficiency in simulating strong TCs. Both observations and HR show larger daily mean EDSL on the western Gulf coast than on the eastern side, highlighting the need for HR climate simulations to improve coastal resilience planning.