层状云数值模式与实际观测研究

改进了一维层状云雨滴分档模式,利用雨滴分档模式在计算雨滴粒子谱型及数浓度自然演变方面中的优势,对吉林省长春市6月21日3个不同时刻的降雨进行了模拟,并与实测资料进行了比较。结果表明,改进后的模式计算稳定,可以模拟出与实际降水谱型相接近的雨滴谱;对于层状云中上升气流速度难以直接测量的问题,通过选用不同的上升气流速度方案,并将计算所得的雷达回波反射率廓线与实际地面雷达观测值相拟和的方法,从而为实现通过雷达回波与模式计算相比较来测量定量降水提供一个新的思路;与实际观测结果比较可知,暖区碰并过程对本次降水的贡献在10%左右,与上升气流的速度有关。

Study on the Stratiform Cloud Numerical Model and Actual Observation

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%.