Effects of Microphysical Processes on the Precipitation Spectrum in a
Strongly Forced Environment
Abstract
This study investigates the effects of microphysical processes on the
precipitation spectrum in a strongly forced environment using a vector
vorticity cloud-resolving model (VVM). Experiments are performed under
imposed advective cooling and moistening with two microphysics
parameterizations: predicted particle properties scheme (P3) and Lin
scheme (VVM-Lin). Even though the domain-averaged precipitation is
similar in two experiments, P3 exhibits stronger extreme precipitation
in the spectrum compared with VVM-Lin. Changes in convective structures
are responsible for such a difference. Using the isentropic analyses, we
identify that in P3, stronger convective updrafts take place in the high
frozen equivalent potential temperature regime where air parcels rarely
reach. This is caused by the reduced melting of rimed ice particles for
energic parcels. Through defining convective core clouds, the relation
between the convective structure on the isentropic diagram and the
extreme precipitation can be identified. The shifts toward extreme
intensity in the precipitation spectrum suggest that the microphysical
processes have significant impacts on the extreme precipitation by the
convective core clouds. The treatment of microphysics has significant
impacts on the convective structures and then alter the probability of
extreme events under the strongly forced environment.