Impact of Cloud Microphysics Parameterizations on Convective and Stratiform Properties for an MC3E Squall Line Case

A cloud microphysics intercomparison study of a mid-latitude mesoscale squall line is performed using the Weather Research & Forecasting (WRF) model at 1-km horizontal grid spacing with eight cloud microphysics schemes to understand specific processes that lead to the large spread of simulated cloud and precipitation at cloud-resolving scales. For the convective core properties, we find that updraft velocity and precipitation have a significant spread across the eight schemes. The spread in simulated updraft velocity correlates well with spreads in both cold pool intensity and latent heating. Updraft velocity variability between schemes is mainly controlled by differences in ice-related parameterizations. For the stratiform, there is a large spread in stratiform area and rain rate distribution. We connect the large differences in the stratifrom rain properties with differences in (a) microphysical parameterizations such as assumed size distribution parameters and (b) updraft properties in the convective region.