Research On The Evolution Characteristics Of Hydrometeors In Thunderstorm Cell With Dual-polarimetric Radar

In order to understand the distribution and evolution of hydrometeors in thunderstorm cell, a fuzzy logic algorithm is described to analyze the evolution characteristics of hydrometeors in typical thunderstorm cells over Beijing by utilizing the 714XDP-A dual-polarization radar parameters and environmental temperature.Furthermore,the phase folding, wavelet de-noising and self-consistent method with constraints (SCWC) are combined in the data's pre-process. The results are as follows.(1) The continuity of differential propagation phase shift(?DP) is been significantly improved for the follow-up work by using the method of checking the differential propagation phase shift's continuity and folding phase back. In the filtering method, the wavelet filter is better than the 13-point moving average filter and the 13-point median filter,which can remove more noise and retain the effective information more completely. In addition, the difference between the reflectivity factor and the S-band radar is reduced by using the self-consistent method with constraints for attenuation correction. After the above study, a complete quality control method based on the folding back, wavelet denoising and self-consistent method with constraints is established.(2) Based on the fuzzy logic algorithm, four kinds of polarized parameters after quality control method and environment temperature are used to identify the 10 types of hydrometeors in the thunderstorm cell, which are drizzle rain(DR),rain(RA), dry snow(DS), dry crystal(DC), wet snow(WS), dry graupel(DG), wet graupel(WG), small hail(SH), large hail(LH), rain and hail(RH). After analysis,the distribution of hydrometeors is quite reasonable. Besides, the results are improved by using environment temperature.(3) According to the macroscopic characteristics of thunderstorm cell, the process is divided into three stages which are development, maturation and dissipation. In the mature stage, the height, the reflectivity factor and the percentages of graupel are obviously higher than those in the development and dissipation stage.(4) The main microphysical processes and evolution characteristics of thunderstorm cell at development, maturation and dissipation stages ars as followed. In the development stage, the main microphysical process below the 0? layer is warm-cloud process. A small amount of liquid hydrometeors rises to the layer above 0? reacting with dry crystal and generates a little graupel which indicates a weak cold cloud process. During the mature stage, there is an enhanced warm-cloud process with DR decreased and RA increased. More liquid hydrometeors can rise to the layer above 0? and there's an enhanced cold cloud process with more graupel. What's more, the graupel in stronger thunderstorm cell can rise above 8km. At last stage,the liquid hydrometeors below 0? layer can't rise to the layer above 0? which lead to the weaker warm and cold cloud process with less graupel above 0? layer.(5) Based on the above results and dynamic characteristic,a microphysical model of the thunderstorm cell's evolution process is established.This study is important for understanding the structure and microphysical processes of thunderstorm cell as well as improving the forecasting of thunderstorm weather.