Influence of Different Precipitation Parameterization Schemes on a Simulated "03.7" Heavy Rainfall Case

Observational and numerical modeling studies have consistently shown that the latent heat release plays an important role in maintenance and development of Meiyu front and frontal precipitation.However,a systematic evaluation of precipitation parameterization schemes(including subgrid-scale convective parameterization schemes and resolvable-scale cloud microphysics schemes) in the simulation of a Meiyu front has been rare in the literature.In order to enhance our understanding of the precipitation process,4 sets of numerical experiments is constructed to evaluate the performance of implicit/explicit schemes which simulates the Meiyu frontal heavy rainfall on 45 July 2003 at grid resolution of 36 km and 12 km with MM5 model.Based on careful research on precipitation region and rainfall,some significative results have been got,which are good for further understanding and predicting mesoscale weather system using mesoscale numerical model.Principal findings are summarized as: The horizontal extent and intensity of precipitation,the partition of explicit precipitation and implicit precipitation are very sensitive to the choice of cumulus parameterization,but it is nearly the same on both the 36-km and 12-km grids for a given cumulus parameterization(except the Betts-Miller scheme);variations in the cumulus parameterization schemes have a much larger impact on the distribution and amount of Meiyu frontal precipitation than that in the explicit scheme at mesoscale grid resolutions of 10 km50 km.