Retrieval of thermal and microphysical variables in observed convective storms. Part II: sensitivity of cloud processes to variation of the microphysical parameterization

Abstract

The largest differeneces in maximum retrieved graupel/hail content and radar reflectivity associate with the parameterizations which fix the graupel/hail distribution intercept parameter or accomplish the riming of supercooled cloud droplets by graupel/hail of a fixed high density. A reduction of the collection efficiency of cloud droplets by snow crystals, while significantly weakening the Bergeron precipitation process, has negligible impact on either the content or riming growth of graupel/hail. The sensitivity of precipitation content to variation of model parameters such as CCN concentration and dispersion of the cloud droplet distribution is relatively weak because the balance among predominant precipitation processes is not significantly altered. Exclusion of the ice phase results in a cooling of up to 2°C in the main updraft region. The major impact on cloud dynamical forcing by presence of the ice phase is a reduction of negative buoyancy in the upper half of the main updraft region. -from Author