A modeling study of surface rainfall processes associated with a torrential rainfall event over Hubei, China, during July 2007.

The surface rainfall processes associated with the torrential rainfall event over Hubei, China, during July 2007 were investigated using a two-dimensional cloud-resolving model. The model integrated the large-scale vertical velocity and zonal wind data from National Centers for Environmental Prediction (NCEP)/Global Data Assimilation System (GDAS) for 5 days. The time and model domain mean surface rain rate was used to identify the onset, mature, and decay periods of rainfall. During the onset period, the descending motion data imposed in the lower troposphere led to a large contribution of stratiform rainfall to the model domain mean surface rainfall. The local atmospheric drying and transport of rain from convective regions mainly contributes to the stratiform rainfall. During the mature periods, the ascending motion data integrated into the model was so strong that water vapor convergence was the dominant process for both convective and stratiform rainfall. Both convective and stratiform rainfalls made important contributions to the model domain mean surface rainfall. During the decay period, descending motion data input into the model prevailed, making stratiform rainfall dominant. Stratiform rainfall was mainly caused by the water vapor convergence over raining stratiform regions. [ABSTRACT FROM AUTHOR]