首页 | 官方网站   微博 | 高级检索  
     


A Simulation Study on the Characteristics of Cloud Microphysics of Heavy Rainfall in the Meiyu Front
Authors:JU Yongmao
Affiliation:Meteorological Center of 61741 Troop PLA, Beijing 100081;Key Laboratory of Regional Climate-Environment Research for Temperate East Asia, Chinese Academy of Sciences, Beijing 100029;Institute of Meteorology, PLA University of Science and Technology, Nanjing 211101;Key Laboratory of Regional Climate-Environment Research for Temperate East Asia, Chinese Academy of Sciences, Beijing 100029
Abstract:A heavy rainfall in the Meiyu front during 4--5 July 2003 is simulated by use of the non-hydrostatic mesoscale model MM5 (V3--6) with different explicit cloud microphysical parameterization schemes. The characteristics of microphysical process of convective cloud are studied by the model outputs. The simulation study reveals that: (1) The mesoscale model MM5 with explicit cloud microphysical process is capable of simulating the instant heavy rainfall in the Meiyu front, the rainfall simulation could be improved significantly as the model resolution is increased, and the Goddard scheme is better than the Reisner or Schultz scheme. (2) The convective cloud in the Meiyu front has a comprehensive structure composed of solid, liquid and vapor phases of water, the mass density of water vapor is the largest one in the cloud; the next one is graupel, while those of ice, snow, rain water and the cloud water are almost same. The height at which mass density peaks for different hydrometeors is almost unchangeable during the heavy rainfall period. The mass density variation of rain water, ice, and graupel are consistent with that of ground precipitation, while that of water vapor in the low levels is 1--2 h earlier than the precipitation. (3) The main contribution to the water vapor budget in the atmosphere is the convergence of vapor flux through advection and convection, which provides the main vapor source of the rainfall. Besides the basic process of the auto-conversion of cloud water to rain water, there is an additional cloud microphysical process that is essential to the formation of instant heavy rainfall, the ice-phase crystals are transformed into graupels first and then the increased graupels mix with cloud water and accelerates the conversion of cloud water to rain water. The positive feedback mechanism between latent heat release and convection is the main cause to maintain and develop the heavy precipitation.
Keywords:MM5  Meiyu front  torrential rain  Goddard cloud microphysical process  TRMM
点击此处可从《Acta Meteorologica Sinica》浏览原始摘要信息
点击此处可从《Acta Meteorologica Sinica》下载全文
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号