Preliminary Results from Numerical Experiments of a Heavy Rain Process with PENN STATE / NCAR MM5

PENN STATE/ NCAR MM5 is used to simulate precipitation of the heavy rain process during 12-13 July 1994. The effects of different PBL parameterizations, resolvable scale moisture schemes and cumulus parameterization on the process rainfall simulation are investigated. By comparing the results of hydrostatic and nonhydrostatic experiments, the nonhydrostatic impact upon precipitation is also examined. It is found in this study that PENN STATE / NCAR MM5 has advantage not only in theory but also in simulating results with real data. In MM5, however, the selection of physical processes, especially water-cycle process, is very important and crucial to precipitation forecast of the case. It is concluded that the model with Grell (1993) scheme for convection and conden?sation method for resolvable scale precipitation captured the rainstorm during 12-13 July 1994 in Beijing area more successfully.