资源环境科技发展态势分析平台

This study explores the impact of a nonhydrostatic dynamical core in high-resolution regional climate simulations using an aquaplanet framework. The Weather Research and Forecasting (WRF) model is used to conduct simulations with both hydrostatic (H) and nonhydrostatic (NH) solvers at horizontal grid spacings (x) of 36, 12, and 4km. The differences between the H and NH simulated precipitation (P) are notable even at x=12km in the intertropical convergence zone and the transition region to the drier subtropics. At gray zone grid spacing (12km and 4km) over the tropics, P is sensitive to whether a cumulus parameterization scheme is used or not. With an idealized Witch of Agnesi land mountain, differences in the precipitation and circulation (vertical velocity) between the H and NH simulations are significant even at x=36km in the tropics due largely to the strong feedbacks related to moist processes. The differences increase as the model grid spacing and mountain half width (a) are reduced, accompanied by a shift toward a more nonhydrostatic flow regime at a=24km. Latent heat release drastically enhances the differences between the NH and H simulations and extends the effect of nonhydrostatic dynamics to a broader region over the mountain and downstream over the tropics. Overall, differences exist between H and NH simulations even at resolutions between 12 and 36km, but the differences are sensitive to the representations of moist physics and other features such as horizontal diffusion used in the WRF model.