Doppler Radar Data In Weather Forecasting

Use intensity field, velocity field, and spectral width information provided by the quantitative measurement techniques of Doppler weather radar, deeply study Doppler weather radar detective information data can provide useful help for artificial weather modification operations, precipitation estimation, analysis of various weather phenomenon, and warning of regional rainfall, etc. In order to fully exert the effect of Doppler weather radar on nowcasting, enhance monitor and early warning power of the strong convective weather systems, and satisfy the need of nowcasting on the development of our society, we must research and develop nowcasting system based on Doppler weather radar fitting for weather characteristic of our country, this is an emergent task.In this thesis, through the study of Hong Kong Doppler weather radar images, combined with mesoscale automatic weather station data and the geographical administrative division map of Guangdong Province and the geographic information of Shanwei City, carries out accurate location to radar echoes, uses numerical analysis to judge the direction, speed and strengthening (weakening) trend of radar echoes, estimates rainfall beginning and end time over the warning area. When radar echo reaches the warning area, sends out warning signal to forecasters to monitor it and start the related emergency response mechanism."Doppler Radar Data Nowcasting System", established by Visual Basic 6.0 programme, used several kinds of common controls to carry out the fouctions of the system, through mouse event techniques to realize the Human-Computer interaction analysis and process of Doppler weather radar images, with friendly interface, easily operation, and steadily operationes. Combined with the needs and methods of weather forecast, the system provides the collection and analysis function of Hong Kong Doppler compound radar images, offers four applied functions to weather forcasters, they functions are:"Precipitation Time Estimation","Precipitation Intensity Calculation","Precipitation Warning Issue", and"System Settings".The system automatically fetches Hong Kong Doppler radar images from the sever computer every six minutes. The program has already implemented the decoding, reducing, decolorizing, and reparing functions of Hong Kong compound radar images from the GIF encode and decode theory, better than calling image processing fuctions of VB iteself. Put forword a method of Doppler weather radar images analysis, the radar echo speed formula based on the graphics theory, the time formula how long the radar echo will reach the warning area, and the automatically warning feasibility conditions of the warning area precipitation. We have already proved the price of the system through the error analysis and the practical application of results in our work.