ESRL/PSD Seminar Series

Abstract

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The western U.S. receives precipitation predominantly during the cold season when storms approach from the Pacific Ocean. The snowpack that accumulates during winter storms provide more than 70% of water supply for the region. Recent studies have documented the role of aerosols to influence clouds and precipitation, with the potential to redistribute and alter the characteristics of precipitation in the mountainous region. These studies have motivated several field experiments to investigate the role of aerosols in cloud microphysical processes and precipitation formation associated with winter storms. Analyses of field measurement data have yielded significant insights and provided the basis to formulate and test different hypotheses about aerosol effects on precipitation. Using data collected from the SUPRECIP2 and CalWater field campaigns, several cases have been selected for modeling aerosol effects under different synoptic environments ranging from postfrontal shallow clouds to deep convective clouds associated with atmospheric rivers in central California. Results from modeling using an explicit bin microphysics scheme will be discussed, with the goal to combine data and modeling to improve our understanding of the linkages between aerosols and precipitation in the topographically diverse region. Additionally, case studies comparing bulk and bin microphysical parameterizations and their influence on precipitation forecasts and assessment of aerosol effects in different cloud systems will be discussed.

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