Intensified Tropical Cyclones in Global Climate Simulations Employing a High-Wind Drag Relation over Sea Surface

Abstract Accurate parameterization of momentum fluxes at high winds across the air–sea interface is crucial for realistically simulating the surface wind fields of tropical cyclones (TCs). Climate models often struggle to reproduce observed TC intensities, particularly surface wind speeds. This study evaluates the performance of a revised surface drag scheme with a capping drag coefficient at high wind speeds in global climate models (GCMs). Our results indicate that the revised surface drag scheme significantly improves the representation of TCs in a statistical sense: (i) Not only the mature intensity but also the maximum 10-m wind speeds throughout the TC life cycle are largely enhanced; (ii) biases in the pressure–wind relationship are notably alleviated, exhibiting reasonable agreement with observations; and (iii) other TC statistical features, such as TC number, central sea level pressure, individual lifetime, and intensification rate, show relatively minor sensitivity to the surface drag schemes. The main reason for the superiority of the revised high-wind drag relation is that the lower drag coefficient in high-wind conditions significantly increases the maximum potential intensity (MPI), indicating a higher theoretical limit for TC intensities. These findings are consistent across different model versions and resolutions, highlighting the robustness of the high-wind surface drag parameterization in controlling the simulated surface wind speeds of TCs in GCMs. Significance Statement Tropical cyclones (TCs) stand out as one of the highly destructive weather phenomena, exerting a significant impact on life and property. Accurate simulations and forecasts of TC activity on a global scale are imperative to mitigate potential losses. However, realistically representing TC intensity in global climate models remains a challenge. This study addresses this issue by employing a revised high-wind surface drag scheme to assess the impact of air–sea momentum fluxes on simulated TC activity. Notably, the revised surface drag scheme yields a significant improvement by enhancing the maximum surface wind speed near the TC centers.