Application Research With A New X-band Multi-parameter Meteorological Radar To Recognize Lightning In Severe Storm

Forming and developing processes of lightning are the results of the interactions between the dynamic processes and cloud microphysical processes, and cloud microphysical processes should not be overlooked. Because lightning occurred in a flash, it is the urgent problem to observe the cloud microphysical processes in a very short period of time for scientists. However the influence of microphysical processes on lightning is significant for better understanding the essence of formation and development of lightning. In this paper, choose the lightning process in Jilin Province of northeast area on May 15, 2007 as a research case. Use multi-parameter radar data, lightning location network monitoring data and automatic weather station precipitation data to analyze the synoptic background, the precipitation process and evolution of cloud infrared images in lightning happening process of the mesoscale convective systems. On this basis, the cloud microphysical changes before and after lightning in the process are analyzed in detail, while further analysis of the influence to the physical processes of precipitation.The results show that the large-scale rainfall and partial strong convective weather due to the course of the mesoscale convective clouds moving from southwest to northeast over Jilin Province. In the process of clouds moving, the front of the cloud gives birth to a strong small-scale convective cloud. By analysis of the change of the various parameters of the multi-parameter radar in the Lightning occurred, we find the polarization parameters of K_DP,φ_dp and Z_DR which closely relate to the occurrence of the lightning. The specific differential phase shift K_DP, differential reflectivity factor Z_DR and differential phase shiftφ_dp change with the orientation of evolved ice particles in the top of the convective cloud before and after occurring of lightning. This could retrieve the changing distribution and structure of the electric field in the cloud. Using this clear discernable direction information of ice particles at the time of lightning has been the better method to forecast the occurrence of lightning. Meanwhile, combined with the strength map we can better analyze the macroscopical changes before and after the lightning. At the same time, use the data of time, location, strength and polarity of the flash occurrence which are provided by lightning positioning network to check the accuracy of the time, location of the lightning forecasted by radar data, this has proved the possibility in using this multi-parameter meteorology radar technology to forecast and monitor lightning earlier. And by analyzing the changes of the data of polarization parameters before and after the lightning in the convection system, we can find the most obvious changes in their respective regions. The changes are fully in line with the theory, but in a parameter-based observation of the other two, are not entirely consistent with the theory, there are some differences. Through the analysis of these differences, we can determine the lightning region.At the same time, further analysis of the relationship between cloud to ground lightning and precipitation in the convective weather systems, we found some strong electrical activity and heavy rainfall which also have a good corresponding relationship in the thunderstorms, and have a poor correlation with general rainfall. The lightning information in mesoscale convective systems can be used to determine the convection process and its development trends and strength. And lightning information can be used to forecast the occurrence and development of convective activity. The total number of lightning doesn't have the clear relationship to the strength of disastrous weather, while the relationship between negative lightning and strength of the thunderstorm weather also doesn't clear. There is only a certain relationship with precipitation. The higher frequency of negative lightning, the stronger precipitation, the reverse is also. Through the analysis of the statistical flash frequency in May 15, 2007, we found the positive lightning with the total flash ratio is not high frequency, but the strong and violent weather phenomenon has obvious. Positive lightning in a high proportion is corresponding with the intense weather phenomena.Furthermore, in order to satisfy the needs of practical figure use, we make software developments for these dual-polarization radar data products. The computer development language is used in Visual C++, introduced interpolation methods for the PPI graphics and RHI graphics and some other key Technology in the development process.