Modeled sensitivity of the Northwestern Pacific upper-ocean response to tropical cyclones in a fully coupled climate model with varying ocean grid resolution

Abstract

Tropical cyclones (TCs) actively contribute to Earth's climate, but TC-climate interactions are largely unexplored in fully coupled models. Here we analyze the upper-ocean response to TCs using a high-resolution Earth system model, in which a 0.5° atmosphere is coupled to an ocean with two different horizontal resolutions: 1°and 0.1°. Both versions of the model produce realistic TC climatologies for the Northwestern Pacific region, as well as the transient surface ocean response. We examined the potential sensitivity of the coupled modeled responses to ocean grid resolution by analyzing TC-induced sea surface cooling, latent heat exchange, and basin-scale ocean heat convergence. We find that sea surface cooling and basin-scale aggregated ocean heat convergence are relatively insensitive to the horizontal ocean grid resolutions considered here, but we find key differences in the poststorm restratification processes related to mesoscale ocean eddies. We estimate the annual basin-scale TC-induced latent heat fluxes are 1.70 ± 0.16 × 1021 J and 1.43 ± 0.16 × 1021 J for the high-resolution and low-resolution model configurations, respectively, which account for roughly 45% of the total TC-induced ocean heat loss from the upper ocean. Results suggest that coupled modeling approaches capable of capturing ocean-atmosphere feedbacks are important for developing a complete understanding of the relationship between TCs and climate.