Technical Methods Study Of Convective Clouds Seeding Effects In Jiangxi Province By Rockets

On the basic of reading and summarizing relevant literatures about the effect of artificial precipitation tests at home and abroad, the effects of clouds seeding which are commonly used in evaluation of inspection methods are summarized in this paper. Researching methods that statistical and physical test combination to use to evaluate the rocket precipitation enhancement process is this topic’s idea and goal.By comparing the advantages and disadvantages of the methods that commonly used in statistical evaluation, the historical regression analysis method which has relatively high effectiveness, is decided to use as statistical test solving the rainfall enhancement process in this paper. Try using hour rainfall and daily rainfall each as statistical variable, the test results of statistical evaluation are analyzed with comparison in this paper. Through learning a variety of physical test methods and studying these methods’ s feasibility, the time series comparison and analysis for cloud units which are based on radar data is decided to be used as physical evaluation in this paper. During the physical evaluation, these five echo parameters which are maximum reflectivity, precipitation flux, echo top, echo volume, vertical integral liquid water content are choosed to use. The seeded cloud units and the unseeded cloud units’ development characteristics are analyzed to get the physics evidence of rainfall enhancement. The comparison unit which is selected are the most similar unit like the seeded unit before the operation.The effects of two rockets precipitation enhancement cases are evaluated using the method of historical regression analysis and time series comparison and analysis for cloud units which are based on regional rainfall data and radar data respectively on Jiangxi Province in June 16, 2014 and July 14, 2013. The results of case in June 16, 2014 showed that: using the historical regression method, the absolute rainfall effect based on hourly rainfall data was 3.14 mm and the relative rainfall effect was 163.58%; the absolute rainfall effect based on daily rainfall data was 67.4mm and the relative effect was 159.1%. Both precipitation effects met the significant level. The results of case in July 14, 2013 showed that: using the historical regression method, the absolute rainfall effect based on hourly rainfall data was 2.25 mm and the relative rainfall effect was 256.58%; the absolute rainfall effect based on daily rainfall data was 10.64 mm and the relative effect was 38.74%. Both precipitation effects met the significant level. The reason of the precipitation enhancement effects’ differences between the daily precipitation data and hour rainfall data may be that the gap of the two kinds of data from time distribution and space distribution is larger and the selected operation period of the two kinds of rainfall data are not uniform length. Using the method of time series comparison and analysis for cloud units which are based on radar data, comparing these five echo parameters’ statistics characteristics before and after the operations between the seeded cloud units and the unseeded cloud units which are most similar to those seeded units’ detected characteristic before operations showed that, obvious positive deviations can be found thus the physical evidence of precipitation enhancement was provided.The effects of a convective rocket rainfall operation are got combining the method of historical regression analysis and the method of time series comparison and analysis for cloud units which are based on regional rainfall data and radar data respectively in this paper. The consequences about statistical effects of the two cases all are positive deviations. Obvious positive deviations were found. The seeding units’ convection has an obvious development after the catalytic impact. The physical evaluation results are consistent with the statistical evaluation results both in these two cases. A convective artificial precipitation process always needs to be evaluated in operations. There is a guide and a reference value that using the test methods described herein for evaluation of a convective process about precipitation enhancement operational by rockets.