Perform Improved Techniques Of The EVAD And Picture Identify Method To Calculate Average Divergence

In this paper, a new improved EVAD technique arithmetic -MGS method which can pick up the value of divergence from Doppler radar basic data is raised, and an operationalized radar product is designed according to this arithmetic. In addition, a picture identify method which utilizes data simulation to pick up divergence quantitatively is raised as well, when the area of radar echo is too little to pick up the divergence according to EVAD technique. Three aspects are introduced mainly:(l)The EVAD technique which is raised by Srivastava is often unsolvable because of usually sick matrix during practice, Thomas and Yue Tao, Dazhang Tang utilize weighted function method to solve the problem separately, in this paper, a modified Gram-Schmidt arithmetic(MGS) is introduced to solve the same problem, according to three improved EVAD methods, basing on two examples to calculate horizontal average divergences and perform alternative solution to adjust the divergences, moreover, performing equation of continuity to calculate vertical air velocities separately, all the results are contrasted and analyzed. The result indicates that MGS method which is raised in this paper is advantage on arithmetic and easier to operate contrasting with Thomas weighted function method and Yue Tao, Dazhang Tang weighted function method, which has a better stability during divergence picking up.(2)It has been proved by lots of actual detected data that thermal or cold advection often overlap with large scale of convergence or divergence, these radial velocity characters of combined wind field are analyzed performing numerical simulation method in the paper, in addition, the influence to these characters by raindrop dripping down velocity is analyzed. The value of convergence or divergence can be gotten quantitatively from identifying radar PPIpictures according to these figures portrayed by numerical simulation.(3)In order to operationalize the research result that is raised in the paper picking-up divergence and vertical air velocity according MGS method, a software which can pick up divergence and vertical air velocity from Doppler radar basic data is designed, how to operate the software is introduced in this paper, and an applicational instance is demonstrated by an actual example.