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The representation of cloud microphysical processes in a global climate model has large impacts on the simulated Earth’s radiative budget and hydrological cycle. Previous work has shown that: a) the artificial treatment of the ice-to-snow conversion process has a large impact on the net radiative balance at the top-of-the-atmosphere; b) the riming process is very important for simulating the convective system, but riming particles are not treated in most global climate models. To address these problems and improve the atmosphere component of E3SM, we have implemented the single-ice-category Predicted Particle Properties (P3) scheme in the model. The scheme has been revised for use at coarser resolutions and to better represent the interaction between processes. We performed single column simulations and global nudged simulations using both P3 and MG2 (the original microphysics scheme) in E3SM and evaluated the simulated cloud and precipitation properties as well as the radiative effects. Results show that E3SM-P3 performs well in simulating macrophysical and microphysical properties of ice clouds. We find large differences between P3 and MG2 in simulating the microphysical process rates and associated latent condensational and radiative heating, which affect the simulated frequency distribution of precipitation and the ratio between convective and stratiform precipitation. The scheme will be further tested and improved in the E3SM next-generation-development project.
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