Cloud-resolving model intercomparison of an MC3E squall line case: Part II. Stratiform precipitation properties

Most of the microphysics schemes underestimate total stratiform precipitation, mainly due to underestimation of stratiform precipitation area. All schemes underestimate the frequency of moderate stratiform rain rates (2-6mm/hr), which may result from low-biased ice number and mass concentrations for 0.2-2-mm diameter particles in the stratiform ice region.

Most simulations overestimate ice water content (IWC) at altitudes above 7km for temperatures colder than -20 degrees C but produce a decrease of IWC approaching the melting level, which is opposite to the trend shown by in situ observations. This leads to general underestimations of stratiform IWC below 5-km altitude and rainwater content above 1-km altitude for a given rain rate. Stratiform precipitation area positively correlates with the convective condensate detrainment flux but is modulated by hydrometeor type, size, and fall speed.