中国北方水汽与云和降水的关系

Relationship between water vapor with cloud and precipitation in the north China

利用中国35°N以北地区1961年1月1日-2001年12月31日58个探空站逐日高空观测资料以及地面观测的逐日总云量、低云量、降水量资料,分析了42a来中国北方各区水汽质量分数的变化特征,水汽质量分数与总云量、低云量以及降水量的年际变化特征,逐区讨论了水汽质量分数与总云量、低云量和降水量的相关关系.结果表明:中国北方地区42a水汽质量分数有微弱的增加;水汽质量分数与云量、降水量呈明显的正相关.水汽质量分数与云量、降水量的相关中,平均水汽质量分数与低云量、降水量的正相关最显著;云量与降水量的相关中,低云量与降水量的相关最显著.这三种相关的季节变化特征均为春季最显著,秋、夏季次之,冬季最弱.沙区的各相关系数均低于非沙区的,说明荒漠化对空中水资源也有一定的影响,尤其是在沙尘暴多发的春季,这一影响就更显著了.

Based on the data of radiosonde report and surface meteorological observation of 58 stations of Jan. 1, 1961-Dec. 31, 2001 of the north China （north of 35°N） for 42 years, the tendency of the water vapor content, cloud cover and precipitation and the relation between them were studied. The result shows that the water vapor content of this area seems to be somewhat increasing during the 42 years; the character of correlation among the water vapor, cloud cover and precipitation shows that, in each region, the correlation coefficients between average water vapor content with low cloud cover and precipitation are the biggest among the correlation coefficients between water vapor content with cloud cover and precipitation; the correlation coefficients between low cloud cover and precipitation are the biggest among the correlation coefficients between cloud cover and precipitation. The seasonal feature of all the three coefficients is that the largest is in the spring, the smallest is in the winter, and the autumn is bigger than summer; the correlation coefficients of desert areas are much lower than the non-desert areas. It reflects that desertifieation has also relatively obvious influence on the air water resources, and the effect tend to be conspicuous especially in spring when the dust storms often occur.