Effects of a dry air‐mass conserving dynamical core on simulating tropical cyclone‐induced gravity waves: A case study of typhoon Ragasa (2025)

This study quantifies the impact of a dry air‐mass conserving (DMC) dynamical core on simulated gravity waves (GWs) induced by typhoon Ragasa (2025) using the Yin–He Global Spectral Model. Both the total air‐mass conserving (TMC) and DMC cores reproduce the observed track, but both lag behind the observed intensity evolution, more remarkable in TMC. DMC produces a stronger typhoon, with enhanced convective updrafts and heavier precipitation, indicating stronger latent heating. Consequently, DMC generates stronger typhoon‐induced GWs, with the largest enhancement during storm development. Relative to DMC, TMC underestimates the 50‐hPa GW intensity proxies (variance of vertical velocity perturbations and absolute vertical momentum flux) by more than 10% during intensification. Stratospheric GW momentum flux and zonal GW forcing diagnostics show that the TMC low bias is concentrated in the mid–lower stratosphere, yet the forcing differences only weakly affect the zonal‐mean zonal wind. Overall, DMC strengthens typhoon convection and GW forcing but modestly impacts large‐scale stratospheric dynamics.