Effects of Microphysical Processes on the Precipitation Spectrum in a Strongly Forced Environment

摘要

This study investigates the effects of microphysical processes on the precipitation spectrum in a strongly forced environment using the vector vorticity cloud‐resolving model (VVM). Experiments are performed under imposed advective cooling and moistening with two microphysics parameterizations: the predicted particle properties scheme (P3) and Lin scheme (VVM‐Lin). Even though the domain‐averaged precipitation is similar in the 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 θei 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. Plain Language Summary The microphysical parameterization typically represents cloud microphysical processes in the numerical models. In this study, the authors implemented a new parameterization (P3) in the model. The results show that extreme precipitation is more likely to occur when the environment is warm and moist compared with the original microphysics scheme. The change of the extreme precipitation is associated with the reduced melting effect in an ascending parcel. The melting of ice particles weakens the upward velocity of the parcel and then reduce the extreme precipitation. P3 can reduce the melting effect by its ability to represent fast‐falling hail particles, which can leave the parcel rapidly.