Mountain precipitation is an important product of orographic flow. It is crucial for farmers whose livelihood depends on the water and for hydroelectric uses in mountainous regions. Thus, the Seeded and Natural Orographic Wintertime Clouds: The Idaho Experiment (SNOWIE) campaign was conducted to ... Show moreMountain precipitation is an important product of orographic flow. It is crucial for farmers whose livelihood depends on the water and for hydroelectric uses in mountainous regions. Thus, the Seeded and Natural Orographic Wintertime Clouds: The Idaho Experiment (SNOWIE) campaign was conducted to understand orographic precipitation and associated microphysical processes such as cloud top generating cells. Cloud top generating cells are small convective elements on the top of the orographic clouds. They exert a large impact on the temporal and spatial distribution of orographic precipitation by producing locally enhanced ice or drizzle. This research aimed to examine whether generating cells observed in the SNOWIE campaign could be simulated using the Weather Research and Forecasting (WRF) model. The simulation was run using three nested domains with a horizontal resolution of 900, 300, and 100 m. The environment was initialized in the 900 m run using two European Center for Medium-Range Weather Forecasts reanalysis datasets (ERA), ERA5 and ERAInterim. To resolve the small-scale generating cells, 300 and 100 m WRF Large Eddy Simulations (LES) were also run. Signals in microphysical and dynamical fields such as cloud mixing ratio, precipitation amount, and vertical motion were analyzed to identify features associated with generating cells. Examining the pattern of these signals in the 100 m run qualitatively indicated cloud-top generating cells. Future work includes modifying the initial and boundary conditions and microphysical backgrounds for the 300 and 100 m resolution domains to test the sensitivity of the cloud top generating cells to environments and aerosols. Show less
