Echo Recognition And Information Retrieval Of Doppler Radar Data

Doppler weather radar has a significant effect on surveilling the mesoscale and mico-scale disastrous weather systems due to its high spatial and temporal resolution as well as its accurate capability in remote sensing. Aiming at the problems in echo recognition and information retrieval of Doppler weather radar, this article make study on recognition and elimination of ground clutter, correlation analysis of clear-air echo with severe convective weather and 3D visualization of radar data.(1) Non-meteorological radar echo has a serious impact on the quantitative application of Doppler radar data, imperative quality control methods such as ground clutter elimination, range folding elimination, velocity dealiasing must be adopted before using radar data. On the basis of existed automatic algorithm for ground clutter detection, this paper compare the SVM (Support Vector Machine) based method to BPANNs(Back Propagation Artificial Neural Networks) based method in precisely identifying the ground clutter echo and precipitous echo, and identifiable recognition accuracy of ground clutter and precipitous echo. The results shows that SVM based method does better in the radar echo identification, especially in the identification of ground clutter echo. On the condition of small sample, SVM based method gets a much better results.(2) The spectrum width data of Doppler weather radar can be utilized to retrieve the turbulent energy dissipation rate of clear-air echo, thus obtaining the turbulent information of environment field. The study shows that:There are always clear-air echo in low levels before convective weather, turbulent motion in low layers intensify drastically.2 or 3 hours before the convective weather, the time measured turbulent energy dissipation rate curve appears a turning point. With the appearance of tendency and the maximum level of turbulent energy dissipation rate reaching 3000cm2·s-3, can the convective weather process be regarded appearing in the soon future.(3) Doppler weather radar can be used to detect the 3D structure of mesoscale weather systems,but the existed product mainly focus on the information of 2D plane, products retrieval the 3D structure is lesser relatively. This paper utilize MATLAB software program platform to realize the reading and displaying function. Choose interpolation algorithm of EPI and Cressman realize the 3D Visualization of Doppler weather radar reflection data. The combination of EPI and Cressman interpolation concludes:the Cressman interpolation has advantages in 3D structure of radar echo, while the EPI shows better in detail section.