Improving Sandstorm Simulations by Parameterizing Form Drag From Subgrid Sand Dunes Using 30‐m‐Resolution Terrain Data

Abstract Surface and near‐surface wind speeds, critical factors for dust emission, are often overestimated in desert regions by models, leading to exaggerated predictions of sandstorm extent and dust concentration. This study implements a new turbulent orographic form drag (TOFD) parameterization scheme using 30‐m‐resolution terrain data in the WRF‐Chem model. Over a 1‐month simulation, this scheme reduced the overestimated surface wind speed by 45%. Compared with observations from 41 meteorological stations and one radio‐sounding station in the Taklimakan Desert, it also decreased the root mean square errors for surface and near‐surface winds by about 20% and 5%, respectively. Furthermore, the 30‐day simulation showed a 31% reduction in PM 10 RMSE and a better‐matched aerosol optical depth distribution. The results demonstrate that the novel TOFD scheme, which utilizes high‐resolution terrain data, effectively resolves dunes and accurately accounts for the drag of small dunes on the near‐surface atmosphere in deserts.