许昌市春季干旱发生频率及人工增雨需求分析

Analysis on the Occurrence Frequency of Drought and the Demand of Artificial Precipitation in Spring in Xuchang City

[目的]分析许昌市春季干旱发生频率、不同降水量级雨日概率分布和人工增雨可作业几率。[方法]选用许昌观测站1953～2010年3—5月降水资料，采用数理统计分析，分析近58年来许昌市春季干旱发生频率和不同降水量级雨日概率分布，并结合人工增雨原理和催化作业技术，分析了该地区人工增雨可作业几率。[结果]许昌春季降水距平百分率变化范围为-83．03％～168．58％，在极端年份会出现严重春旱和春涝；春季干旱发生频率为36．2％，平均每2．8年出现一次；春季降水距平百分率Pa≤-50％的年份有10年，且近年来Pa≤-50％的年份明显增加；春季出现1．0～2．9和5．0～9．9mm降水量级雨日的概率较大，分别为36．4％和26．3％；春李降水距平百分率Pa为正距平年份有22年。许昌春季3mm以上降水量级的作业机会平均有8次，5mm以上和10mm以上降水量级的作业机会平均分别为6和3次。[结论]该研究为该地区抗灾减灾、合理开发利用空中云水资源提供科学依据。

[ Objective] The research aimed to analyze the occurrence frequency of drought, the probability distribution of the different grade precipitation days and the operation risk of artificial precipitation in spring. [ Method ] Using the 3 - 5 month precipitation data of the Xuchang observation station from 1953 to 2010 ,the occurrence frequency of drought and the probability distribution of the different grade precipitation rain days were analyzed by the mathematical statistic analysis, and combined with the principle of artificial precipitation and the catalytic activi- ty technology, the operating probability of artificial precipitation was analyzed in Xuehang. [ Result] The precipitation anomaly percentage range was 83.03% - 168.58% in spring in Xuehang,and in extreme year there will be a severe drought and spring floods. The spring drought fre- quency was 36.2%, the average once every 2.8 years. The precipitation anomaly percentage less than or equal to 50% of the year has 10 years, and in recent years, the year of Pa less than or equal to 50% was obviously increase in spring. The probability of the 1.0 - 2.9 and 5.0- 9.9 mm rainfall level rain days were larger,36.4% and 26.3% respectively. The positive anomaly of precipitation anomaly percentage was 22 years. The average operating probability of more than 3 mm rainfall level was eight times,that of more than 5 mm and 10 mm rainfall level was six and three respectively in spring in Xuchang. [ Conclusion] The study provides the scientific basis for the disaster mitigation and the the reasonable development and utilization of the cloud water resource in the air.