The response of convectively generated gravity waves to sea surface temperature variations revealed by Aquaplanet simulations

Abstract Deep convection is a major source of stratospheric gravity waves (GWs) in the tropics, with their intensity and frequency significantly influenced by sea surface temperature (SST). This study investigates the response of lower‐stratospheric convectively generated gravity waves (CGGWs) to varying SSTs using idealized simulations from the Radiative‐Convective Equilibrium Model Intercomparison Project. The analysis focuses on convective sources, thermal and mechanical forcings, and background atmospheric conditions. The results show that the intensity of lower‐stratospheric CGGWs generally increases with rising SST, primarily due to enhanced thermal forcing, with the upward shift of the tropopause also contributing to this intensification. Multimodel analyses, both with and without convective aggregation, consistently show that thermal forcing strengthens with rising SST, suggesting that stronger latent heating is not primarily driven by increased aggregation. The response of mechanical forcing, however, is model‐dependent, exhibiting varied responses across simulations, ranging from enhancement to invariance, which introduces uncertainty in the CGGW response. These findings highlight the critical role of thermal forcing in CGGW intensification, while also emphasizing the importance of mechanical forcing, which is more model‐dependent and may even dominate under certain conditions. Furthermore, despite the use of simplified idealized configurations, considerable intermodel differences remain in mean states such as precipitation rate, convection organization, and vertical velocity, which also introduce uncertainty in the impacts on GWs. This highlights the model dependence of simulated CGGWs and their response to SST, adding uncertainty to simulations of middle atmospheric circulation under future warming scenarios.