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How do dust and marine aerosols impact snow precipitation over the western US mountainous region?

Presentation Date
Tuesday, December 13, 2022 at 9:30am - Tuesday, December 13, 2022 at 9:40am
Location
McCormick Place - E253cd
Authors

Author

Abstract

Understanding the factors contributing to snow precipitation over the mountains has important implications for predicting the hydrology and local climate. Aerosol is one of the environmental factors that affect clouds and precipitation. In the western US, our understanding of how different types of aerosols would affect snow precipitation in the mountainous region is still limited. We conducted model simulations at 1 km grid spacings with a detailed bin microphysics scheme to investigate the aerosol impacts on orographic mixed-phase clouds and precipitation, focusing on ice-nucleating particles (INP) from dust and marine aerosols, with the case studies from a series of CalWater field campaigns and the ACAPEX field campaign. We found that increasing dust INPs enhance snow precipitation through enhanced deposition and riming. It also dramatically reduces supercooled water content and increases the cloud glaciation temperature. The marine INPs enhance the formation of ice and snow, leading to less shallow warm clouds but more mixed-phase and deep clouds, increased ice water path (over 5 times), and snow precipitation. The responses of cloud and precipitation to marine INPs vary with the stages of the atmospheric river (AR) with more significant effects at the early stages, mainly because the moisture and temperature conditions change with the AR evolution. Those studies improve our understanding of aerosol impacts on orographic clouds and precipitation in the western US.

Funding Program Area(s)
Additional Resources:
NERSC