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A series of 3D predictions,dealing with the development of a heavy storm observed during the OSCAR experiment,were carried out by utilizing the PERIDOT model,and introducing alternatively the cumulus parameterization schemeof Bougeault (1985) and the prognostic one (Chen,1989;Chen and Bougeault,1993),with three different grid sizes:160 km,80 km,40 km.The feasibility of the new prognostic scheme and its improvement on the problem of dependencyof the predicted rainfall upon the grid size of the numerical model were verified by comparison of the rainfall observedand those predicted.The results demonstrate that,in general,the predicted rainfall increases when the grid size decreases for bothdiagnostic and prognostic schemes.However,with the new prognostic scheme,the numerical model is capable,on theone hand,for the larger grid sizes,to increase the rainfall,which is under-estimated with the scheme of Bougeault(1985);on the another hand,for the smaller grid sizes,to reduce the rainfall,which is usually over-estimated.In otherword,there is an obvious improvement on the problem under study.
A series of 3D predictions, dealing with the development of a heavy storm observed during the OSCAR experiment, were carried out by utilizing the PERIDOT model, and introducing alternatively the cumulus parameterization scheme of Bougeault (1985) and the prognosticone (Chen, 1989; Chen and Bougeault, 1993) with three different grid sizes: 160 km, 80 km, 40 km. The feasibility of the new prognostic scheme and its improvement on the problem of dependencyof the predicted rainfall upon the grid size of the numerical model were verified by comparison of the rainfall observedand those predicted that results demonstrate that, in general, the predicted rainfall increases when the grid decrease decrease for both diagnostic and prognostic schemes. With the new prognostic scheme, the numerical model is capable, on theone hand, for the larger grid sizes, to increase the rainfall, which is under-estimated with the scheme of Bougeault (1985); on the another hand, for the smaller grid sizes, to reduce the rainfall, whic h is usually over-estimated.In otherword, there is an obvious improvement on the problem under study.