中文摘要：

根据1961-2008年全国210个台站的地面气象要素资料，发现地面水汽压与降水量之间的经验关系，建立了由降水量估算地面水汽压的经验表达式，由此进一步求得天文选址所需考察的大气水汽含量．研究结果表明，不同季节的地面水汽压同降水量之间存在着稳定的函数对应关系，利用各地区的降水量计算出的水汽压，符合当地水汽压的实际测量，所求得的各地区大气水汽含量也均能较好地反映当地长年平均情况．

英文摘要：

Based on the database of the 210 ground meteorological stations over China from 1961 to 2008, the empirical relation between ground water vapor pressure and precipitation is discovered. Then the equations used for estimating ground water vapor pressure based on precipitation are developed. The precipitable water vapor is one of the important parameters for astronomical site survey. With this study, we can develop a new method to obtain the precipitable water vapor of specific area or over China with the only available precipitation. The results show that the relation is quite stable in different seasons. The calculated water vapor pressure is well consistent with the practical measurements, and the calculated precipitable water vapor corresponds well with the local long-term average.