Combined Application Of Various Types Of Weather Radar In Monitoring Of High-Impact Weather In The West Coast Of Taiwan Strait

As one of the regions with frequent high impact weather,the southeast coast of China has different nowcasting difficulties from other regions.The hilly landform in the east of the Wuyi Mountains is the main underlying surface feature,and the topographic impact of the central mountain range of Taiwan Island makes it difficult to predict the development and evolution of disastrous weather systems such as severe convection and typhoon on the west side of the Strait.To better strengthen the nowcasting capability of high impact weather,multiple types of weather radars are gradually built and applied for operational.The technology of dual-polarization and phased array can provide more observation information for operators.However,many problems also follow:what are the differences between radar products of different bands and scanning modes,what role they play in the monitoring and early warning process,and how to apply them to the characteristics of the high impact weather system in the west coast of the Taiwan Strait.In this paper,the fusion application method is studied around the main disastrous weather in the west coast of the Taiwan Strait using the observation data of the Taiwan Strait regional multi weather radar network.The main research methods and conclusions are as follows,（1）Based on the use of S-band dual polarization radar and X-band phased array radar,the comparative analysis of observation data of two types of weather radar is carried out.The results show that S-band dual polarization radar,as the main operational radar for weather monitoring,has stable performance.X-band radar has the advantage of high time-space resolution,but there is a serious problem of attenuation.Therefore,the role of X-band radar networking is high time-space resolution monitoring,And supplementary observation of the blind area of S-band operational radar.（2）According to the existing radar network on the west coast of the Taiwan Strait,the application methods of 3D wind field inversion technology in different scale weather systems and the advantages of X-band phased array radar network inversion are analyzed,and the combined application analysis of multiple radars in the convection system is carried out.The results show that the combined application effect of 3D wind field inversion technology of multiple band radars is good.（3）Analyze the morphological characteristics of the spatial distribution of the dual polarization parameter Z_DR in the severe convection,confirm that the Z_DR column can be used as a reference for the change trend of the updraft intensity and the spatial position,and propose a localization algorithm for automatic identification and echo propagation direction extraction,which has been applied in the prediction and early warning operations.（4）On the basis of multi radar wind field retrieve technology and Z_DR column identification algorithm,the dynamic structure evolution characteristics of a convective system merging process are analyzed.Through the combined application of dual polarization parameters and three-dimensional wind field retrieve technology,a conceptual model of local gale formation is proposed,which deepens the understanding of the convection merging mechanism by operators.（5）The combined application analysis of typhoon"Meranti"（2016）is carried out by using weather radars on both sides of the Taiwan Straits.The retrieval area of the coastal radar for the typhoon core structure is expanded through the GBVTD（Ground-Based Velocity Track Display）technology,revealing the characteristics of the asymmetric structure change of typhoon in the Taiwan Straits area.At the same time,the applicability of the GBVTD technology in the Taiwan Straits area is demonstrated,and the channel networking scheme of Doppler weather radar is proposed,it provides reference for joint prevention of disastrous weather across the Straits.