Modeling Atmospheric Dust and Its Radiative Forcing with a Global Variable-resolution Model: Impacts of Mesh Spacing and Size Distribution

Abstract:

Desert dust has been suggested as the main contributor to the global aerosol burden, and plays an important role in regional and global climate system. There have been increasing efforts to improve the dust modeling in the last decades. Previous studies found that dust modeling results may be sensitive to the model resolution and dust size distributions. In this study, a novel modeling framework of atmospheric dust based on the Model for Prediction Across Scales (MPAS) is first introduced and evaluated in this study. The dust in the atmosphere is simulated simultaneously with the meteorological fields, and the climatic impacts of dust are considered in the model. The developed modeling framework is used to investigate the impacts of size resolution of atmospheric dust on its transport, deposition, and radiative forcing at global scale. In addition, the experiments are conducted at multiple horizontal resolutions, including global quasi-uniform resolutions of 120 km and 30 km and global variable resolution of 128-32km with the refinement region over East Asia. These experiments with different resolutions are analyzed to understand the impacts of mesh spacing on global emission and transport of dust, and also the regional transport of East Asian dust to the Tibetan Plateau.