Sensitivity of Orographic Precipitation to Ice Microphysics Parameter Perturbation

Orographic precipitation plays a vital role in providing water resources to mountain communities, as well as having adverse impacts such as flooding. Complex interactions between the dynamics, thermodynamics, and cloud microphysics can control precipitation type, amount, and its location over a mountain. Orographic precipitation is known to be sensitive to the upwind sounding and microphysics, but disentangling these factors is a challenge. This study aims to further explore the microphysical controls on surface precipitation, cloud development, and dynamics by performing idealized simulations of moist neutral flow over two-dimensional topography. CM1 model simulations are performed using an idealized upwind sounding derived from the November 13, 2015 OLYMPEX extreme precipitation event. Changes to parameters in the Morrison microphysics scheme are used to assess the impact that a variety of settings associated with frozen hydrometeors have on surface precipitation and orographic flow and cloud development.