Warm Aerosol-Cloud-Precipitation Interactions in Complex Terrain

A 3D LES model with detailed cloud and precipitation microphysics is used to investigate the impact of aerosol-cloud-precipitation interactions (ACPI) in the diurnal cycle of clouds, including low level clouds and fog, and precipitation across scales with a focus on impacts on the surface energy budget and the climate near the ground. The model is built upon CM1 (G. H. Bryan and J. M. Fritsch 2002) by replacing bulk parameterization with detailed bin microphysics (Duan et al. 2019; Prat and Barros 2007) and introducing a land-surface model. Here we present first results of the simulation of low level orographic cumulus clouds in the inner southern Appalachian Mountains with evaluation against observations during the Integrated Precipitation and Hydrology Experiment in 2014 (IPHEx) (Barros et al. 2014). Also, we present sensitivity analysis of model inputs of both aerosol, environmental conditions, and land surface properties and examine the spatial relationships between ACPI and forest diversity. The parameter-associated uncertainty in the representation of clouds and rainfall processes is also discussed in the context of capturing the observed dynamic evolution of clouds and precipitation.

Barros, A. P., and Coauthors, 2014: NASA GPM-Ground Validation: Integrated Precipitation and Hydrology Experiment 2014 Science Plan. Duke University, Durham, NC, https://doi.org/10.7924/G8CC0XMR.

Duan, Y., M. D. Petters, and A. P. Barros, 2019: Understanding aerosol–cloud interactions through modeling the development of orographic cumulus congestus during IPHEx. Atmospheric Chemistry and Physics, 19, 1413–1437, https://doi.org/10.5194/acp-19-1413-2019.

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Prat, O. P., and A. P. Barros, 2007: A Robust Numerical Solution of the Stochastic Collection–Breakup Equation for Warm Rain. Journal of Applied Meteorology and Climatology, 46, 1480–1497, https://doi.org/10.1175/JAM2544.1.