Improvement And Application Research On Statistical Evaluation Method Of Artificial Precipitation Enhancement Effect Of Cold Clouds

Water is not only the important component and object of earth system science, but also the important resources that the mankind rely on existence. To encounter the stem situation that there is a shortage of water resources in China, artificial precipitation enhancement is an important approach. Howere, since the macro or micro process of cloud and precipitation has not been mastered and simulated accurately yet, it is still a problem to determine some scientific method for the evaluation of artificial precipitation enhancement. So, the evaluation of artificial precipitation enhancement is both an important operational content and research content in meteorology. Considering the remaining difficulty in non-randomized artificial precipitation enhancement, and the difference conditions between China and other countries, we cannot replicate their method directly, and it is necessary to conduct a further research on the evaluation method and its application.In this article, the improvement and application on statistical evaluation method of cold-cloud artificial precipitation enhancement was studied with the data including rail-gauge, weather radar and the operation information of artificial precipitation enhancement from several provinces, which based on the cold-cloud seeding mechanism especially by AgI. For the operation that the stratiform cold-cloud was seeded by aircraft in large-scale, the approach to determine the affected zone and the effect on statistic model caused by rainfall grid interpolation was studied, and then a software based on above was developed. For the convective cloud seeded by ground instruments, the statistical evaluation method based on radar data along with physical evaluation and numerical simulation were used to research the statistical feature respond to seeding.Firstly, for the purpose of getting a more sensible affected area to count in practice, a three-dimension stratiform cold-cloud seeding numerical model was built under ideal condition. And the positive correlation between the wind speed in seeding level and the range of rainfall enhancement area was preliminary demonstrated by a series of seeding numerical experiments as well was the nature cloud simulation. And then a VB+MO method was introduced to determine the range of affected area,helping to calculate the area and judging the inner or outer side of an irregular zone, which promoted the convenience and soundness of affected area determination.Secondly, by comparing the result conducted from raw rainfall station data and two sets of grid interpolation data in different spatial resolution, it was found that there will be more clusters in higher spatial resolution interpolation, and more variables passed the step-regression. The pertinence, rationality and reliability in statistical model were all improved, which made the evaluation a step further in quantitative than in qualitative. And the calculate result was testified preliminarily by physical evaluation method based on weather radar data.Moreover, a software for statistical evaluation on the effect of aircraft precipitation enhancement was developed, which was based on the research above coupled with CA-FCM(Cluster Analysis-Floating Control Area) method. And its utility and replication was proofed by its application in Shandong and Qinghai province.Meanwhile, a propagating storm process was studied by statistical method, along with the hydrometeor classification analysis based on dual-polarization radar and numerical simulation. The decay rate of Zmax in the decay phase of a storm was found to be a statistical feature respond to cold-cloud overseeding, which was argued preliminary for the mechanism that ice-phase particle increased due to seeding caused the decreasing of rain.