Mesocyclone Recognition And Three-dimensional Reconstruction

The paper is a part of"the research on the recognition of hailstone based on the characteristics of cell and evolution law", which is sponsored by scientific fund for City meteorological study.Hailstone is a type of natural disaster which not only causes inconvenience to people's daily life but also result in serious damage to industry and agriculture. If we can forecast where and when it will happen, we can prevent hailstone for the sake of the least damage. With the increasing application of Doppler radar as an effective tool of detecting severe convective weather, domestic and overseas researchers found that the mesocyclone has a close relationship with catastrophic weather, such as storm, strong wind, hail, and so on. Therefore, the information of mesocyclone which is provided by Doppler radar has an obvious advantage in pre-alarming of the severe weather and tornado accurately and in time.The paper discussed the characteristics of mesocyclone, especially the features of radial velocity distribution and velocity image in different wind backgrounds. Then with expert's experience, mesocyclone was recognized and reconstructed in three-dimension (3D) based on theories of image processing and pattern recognition.The paper mainly includes two parts:(1) The recognition of mesocyclone. The region of interest (ROI) in the reflection image was obtained, and then mesocyclone was recognized in ROI in terms of shape characteristics and shear. The algorithm of area growth was applied to remove small fragments. However, the algorithm needs too much time; the paper optimized the algorithm with OpenCV. which can enhance the calculation speed and ensure recognition veracity.(2) The three-dimension reconstruction of mesocyclone. According to the theory of three dimension reconstruction, the part extracted contours of cloud from mutli-elevation radar image to reconstruct the cloud. The research on the aspect is helpful for further research.The experiments which showed the methods of the paper can recognize mesocyclone accurately, and can acquire the high calculation speed. The image which was reconstructed in 3D showed three-dimensional structure of mesocyclone. which established solid foundation for the development of whole system in the future.