What is incorrect in hail recognition of dual-polarization radar is that

What is incorrect in hail recognition of dual-polarization radar is that KDP is close to zero.

The size of hail directly affects the degree of weather disasters, especially the large hail with a diameter of more than 2 cm does great harm to crops, which is the focus of hail early warning and forecasting. The country is upgrading its dual-polarization radar. At present, the hail probability detection and size estimation of dual-polarization radar still come from the hail algorithm hda of single-polarization radar.

Hda algorithm estimates the probability of hail of any size, the probability of strong hail and the maximum expected hail size produced by detected storm cells, which has the problem that the predicted hail size is obviously too large. Differential reflectivity factor of dual-polarization radar.

technical background

Polarization parameters such as correlation coefficient cc show great advantages in hail identification, and operational radar can identify hail or mixed phase state of hail and precipitation by using water vapor condensation classification algorithm hca. At present, the research on hail based on dual-polarization radar mainly focuses on the evolution of hail cases and dynamic microphysical characteristics of hail clouds, and there is no algorithm to identify hail size categories based on dual-polarization radar.

Ortega et al. used more than 3000 hail data to verify and analyze the validity of hsda, which is going to replace the hail identified in the particle phase classification algorithm hca currently used by S-band radar of weather radar network.

Technical realization elements

The technical problem to be solved by the invention is to provide a method for identifying hail size classification by using dual-polarization radar, so as to realize the identification conforming to the domestic hail size classification and improve the accuracy of the identification result. In order to solve the above technical problems, the technical scheme adopted by the invention is a method for identifying hail size by using dual-polarization radar.

Subdivide the height layer into 7 layers; Screening hail events, by analyzing the box diagram and scatter diagram, the distribution characteristics of dual polarization parameters of three types of hail at different heights are counted, and the threshold of localization membership function is determined. Three kinds of hail refer to small hail, big hail and extra-large hail.