| Based on WRF3.4 version, two strong convective weather occurred in Yangtze-Huaihe Region during the Meiyu period is simulated and analyzed, both of two cases use MY two-moment microphysical scheme. WRFV3.4 model shows a good simulation ability for two strong convective precipitation processes with different intensities. We study the influence and mechanism on different deep convective weather macro micro characteristics of the changing spectral shape parameters of raindrop and graupel by a serious of sensitivity experiments of the main particles(raindrop,graupel) spectral shape parameters in convective clouds.It is found that the variation of raindrop and graupel spectral shape parameters has a significant effect on the cumulative rainfall in strong rainfall(Case 1),but a little impact on the cumulative rainfall in hail weather(Case 2),and a great impact on the cumulative hail(Case 2). The analysis of spatial and temporal distribution characteristics of water content in the two cases of sensitivity tests,the distribution of raindrops and graupel in Example 1 is greatly affected by spectral shape parameters of raindrop and graupel. When the spectral shape parameter of raindrops increases, the ratio of graupel and rainwater increases firstly and then decreases, but number concentration decreases. When the spectral shape parameter of graupel increases, the ratio of rain water decreases, and the number concentration of raindrops and graupel decreases slightly. The radius of the raindrop increases with the increasing of the spectral shape parameter of raindrops, while the spectral shape parameter of graupel increases, more graupel is distributed at lower layer. The change of spectral shape parameter of raindrops and graupel in 2 cases has a great influence on the distribution of graupel and hail. When spectral shape parameter of raindrops increase, the ration of hail decreases firstly then increases, and the ration of hail slightly decreases. When the spectral shape parameter of graupel increases,the ration of graupel increases,but the number of concentrations decreases, the radius increase. By analyzing the microphysical transformation term in the cloud, we can further find out the reason that the spectral parameters affect the simulation results. The change of the spectral shape parameter of raindrops and graupel in case 1 affects the micro-physical processes associated with rainwater and graupe. The main source of rainwater is the melting of the graupel,which decreases with the increase of the spectral shape parameter of graupel increases, is in accordance with the change of cumulative rainfall. The main sink of rainwater is the evaporation,when the spectral shape parameter of raindrop increase, raindrop evaporation increases firstly and then decreases. The growth of the gravel is mainly due to the increase of the parabolic parameters. Graupel comes mainly from the collision of the graupel and the cloud, which decreases with the increase of the spectral shape parameter of graupel increases.In case 2, there was a great influence on the source and sink of the graupel and hail. The melting of the graupel decreases with the increasing of the spectral shape parameter of raindrops. With the increasing of the spectral shape parameter of graupel, the melting of the graupel is distributed at the lower level. The main source of hail is collision of hail and rain and conversion of hail by graupel. Both of them increase firstly and then decrease with the spectral shape parameter of raindrops changing. It is also in accordance with the change of cumulative hail.In summary, the spectral shape parameter of raindrops and graupel have influence on the simulation results of heavy convective rainfall and hail weather in some degree, and the variation of the spectral shape parameter of the two particles will affect the spatial and temporal distribution of the particles in the cloud and microphysical process, thus it lead to the difference of precipitation and hail distribution and magnitude. |
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