Study on the Stratiform Cloud Numerical Model and Actual Observation
层状云数值模式与实际观测研究

With the help of the improved one-dimensional stratiform cloud raindrop category model,in this thesis,we have simulated the three different precipitations in Changchun,Jilin Province,on June 21,2005 and made a comparison between the results and the data obtained through actual observation,taking advantage of the stratiform cloud raindrop category model in calculating the raindrop spectrum and the natural development of the precipitation intensity.The results show that the improved model tends to be much more stable in calculating and it can simulate the raindrop spectrum closest to the actual precipitation spectrum.Succeeding in solving the problem that it is difficult to directly measure the updraft velocity of the strtiform cloud,we fit the data calculated in various schemes of updraft velocity with the actual radar echo profile below the zero-temperature level,and therefore achieve the aim of measuring the quantitative precipitation via comparison of the radar echo with the model.The comparison between the data simulated and those actually observed reveals that due to the updraft velocity the contribution that the collision process in warm area has made to this precipitation is about 10%.