Gravity waves significantly influence the atmospheric circulation in the tropics; however, they are still not well represented in weather and climate models. The generation and propagation of gravity waves over mountains in the tropics are complex because several mechanisms can be involved, for example, the roles of mountains and deep convection. In this study, we use the Western Ghats Mountains in India as a case to compare orographic and convective driven gravity waves using high-resolution cloud resolving simulations. Satellite observations and global reanalyses are used to validate the control simulation. In addition to the control simulation, sensitivity simulations are conducted to explore the role of each physical forcing. A no-mountain simulation, with all terrain removed, is used to identify the role of topography in shaping gravity waves. A no-latent-heating simulation, in which the latent heating of convection is disabled, is used to understand the impacts of latent heating on gravity waves. We apply quantitative diagnostics of gravity waves to all the simulations to compare the gravity wave features and understand the physical processes associated with the gravity waves. The momentum flux, energy flux, and other gravity wave quantities identified in the diagnostics allow an objective comparison between the simulations. This study will also initiate a broader inter-comparison of gravity waves across other tropical mountain regions, e.g., West Africa, East Africa, and Myanmar. These comparisons will improve our understanding of gravity waves over the tropical mountains from a global perspective.

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*email: gang.zhang@yale.edu
*Preference: Oral