A simulating study on resolvable-scale microphysical parameterization in amesoscale model

The Penn State/NCAR Mesoscale Model (MM5) is used to; simulate the-precipit ation event that occurred during 1-2 May 1994 to the south of the Yangtze R iver. In five experiments the Kain-Fritsch scheme is made use of for the su bgrid-scale convective precipitation, but five different resolvable-scale m icrophysical parameterization schemes are employed. They are the simple sup er-saturation removal scheme, the warm rain scheme of Hsie et al. (1984), t he simple ice scheme of Dudhia (1989), the complex mixed-phase scheme devel oped by Reisner et al. (1993), and the GSFC microphysical scheme with graup el. Our interest is how the various resolvable-scale schemes affect the dom ain-averaged precipitation, the precipitation distribution, the sea level p ressure, the cloud water and the cloud ice. Through a series of experiments about a warm sector rainfall case, results show that although the different resolvable-scale scheme is used, the diffe rences of the precipitation characteristics among all five runs are not ver y obvious. However, the precipitation is over-predicted and the strong meso scale low is produced by the simple super-saturation removal Scheme. The wa rm rain-scheme with the inclusion of condensation and evaporation under-pre dicts the precipitation and allows the cloud water to reach the 300 hPa lev el. The scheme of the addition of graupel increases the resolvable-scale pr ecipitation by about 20%-30%. The inclusion of supercooled liquid water-in the grid-scale scheme does not affect significantly the results.