Research On 3D Visualization Method Of Weather Radar Base Data

Because of the high temporal-spatial resolution,the doppler radar has become an important tool for monitoring small scale convective weather system in the field of meteorological business.The weather radar can be used to detect the three-dimensional structure of atmospheric environment field.But most of weather radar products in China are still concentrated on displaying data in two dimensional plane at present,and products of three dimensional reconstruction of radar data are very few.Therefore,it is urgently needed to extract three dimensional information from radar echo data and do three dimensional reconstruction in the field of scientific research and business.In the paper,the weather radar data are spatially interpolated,and volume rendering algorithm and surface rendering algorithm of the computer graphics are used to do the research on 3D Visualization of voluminal scan data of radar.1.Due to the characteristics of weather radar data,the distribution of sampling sites of data is not very uniform in horizontal and vertical directions.And it's difficult to do three dimensional reconstruction and data assimilation on the basis of regular grids.Thus,the radar data need to be interpolated into regular grids by using the method of three dimensional interpolation.According to several classical algorithms proposed by predecessors,they are all implemented in this paper.Through comparison,it is found that Barnes is the most suitable for 3D interpolation and finishing the preprocessing of radar data.2.The algorithm of Marching Cubes(MC for short)in the surface rendering algorithm is used to do three dimensional reconstruction of radar echo data.During using traditional algorithm of MC,it is found that there is a waste of storage space and high data redundancy in the process of constructing isosurface.By combining the method of MC with the method of MT,an improved algorithm of MC is proposed.Compared with the two different algorithms,the improved algorithm of MC can save about 90 percent of storage space and reduce operation time by an average of more than 80 percent.Among rendering effects of voluminal scan data of radar,the improved algorithm of MC is much better than the traditional algorithm of MC in drawing the isosurface of a wide range of cloud.And when drawing small cloud,the improved algorithm of MC is of good drawing ability.3.The ray casting algorithm in volume rendering algorithm is used in this paper.The rendering effect of the ray casting algorithm is good,but it has high complexity and low efficiency which is disadvantageous to interactive processing.Therefore,the speed of algorithm needs to be accelerated.An improved ray casting algorithm is proposed to process radar data in this paper,and the space leaping technique is used to accelerate the speed of this algorithm.With GPU acceleration technology and compared with the original algorithm,rendering effect and the efficiency of the improved algorithm is better.At last,the interactive operations like zoom,rotation and slicing are also realized,and the observed effect of 3-dimensional body is enhanced.