近45a郑州夏季大气可降水量及其降水转化率分析

根据郑州站1964—2008年月平均探空资料及地面降水资料，分析了近45a郑州夏季大气可降水量和地面降水量的演变特征，并在此基础上讨论了与该站夏季降水转化率的关系。结果表明：（1）郑州站夏季可降水量和降水量存在明显的年际变化，可降水量存在准2a的振荡，而降水量主要表现出准4～6a的振荡周期；（2）在长期线性趋势上，可降水量呈微弱的下降趋势，而降水量呈线性上升趋势，两者都在1990年代末发生突变；（3）郑州站夏季降水转化率与降水量存在相同的年际振荡周期和线性增加趋势，其降水转化率在21世纪初发生突变。

Precipitable Water and the Precipitation Conversion Efficiency in Summer During the Recent 45 Years in Zhengzhou

By using the monthly mean data of radiosonde observations and precipitation at the weather station of Zhengzhou from 1964 to 2008, the evolution characteristics of precipitable water and precipitation in summer were analyzed. On the basis of that, the relation- ship between them and the conversion efficiency of precipitation in summer was discussed. The results show that there were obviously annual variations for the precipitable water and precipitation in summer in Zhengzhou, and the quasi - periodic oscillation of the sum- mer precipitable water was 2 years, which was 4 to 6 years for the summer precipitation. The precipitable water presented a weak de- cline trend in the past 45 years, while the precipitation had an insignificant increase trend, but both of them occurred mutation in the late of the 1990s. The precipitation conversion efficiency had similar inter -annual oscillation and linear increasing trend, but the mu- tation occurred in the early 21 st century.