1.Institute of Atmospheric Physics,Chinese Academy of Sciences;2.Beijing Weather Modification Office
To characterize the microphysical characteristics and transformation process of stratiform cloud with embedded convections, a case study was performed using WRFV3 model based on two aircraft measurements on May 1st, 2009. The aircraft observation results showed that the shapes and formation process of ice particles existed significant difference between the regions of stratiform cloud and embedded convection . Compared to the embedded convection region, the shapes of ice crystals in the stratiform cloud was more complicated, including the needle column, capped column and dendrite type. However, the dendrite type ice crystals dominated in the embedded convection region and their growth was controlled by aggregation and riming processes. Overall, the results indicated that the basic characteristics of this stratiform cloud with embedded convections simulated by the WRF model were in good agreement with the aircraft observations, including cloud distribution, LWC and numerical concentration on the flight route, etc. The simulated results showed that in the stratiform cloud, with higher cloud water content and bigger W, could develop into embedded convection because of strong riming process. The hydrometeors of snow, graupel and rain water in the clouds account for 51.9%, 31.0%, 16.0%, respectively, cloud ice and cloud water accounts for very little. In higher level, snow and graupel grew through deposition process. In lower level, they grew through riming process and melted into rain. Stratiform cloud with lower cloud water content and smaller W, would stay to be stratiform cloud. The hydrometeors of snow, rain water and cloud ice account for 90.4%, 6.1% and 3.5%. The ice and snow grew through depositon process, and melted into rain in lower level.