基于温度与湿度的大气降水同位素特征影响因素分析

Research on the Precipitation Isotope Effect Factor Based on Temperature and Humidity

以西安地区为例研究了近八年的大气降水的氢氧同位素组成,提出了大气降水线的方程,并与全球大气降水线对比,揭示了当地大气降水线的特征,分析了温度、降水量对大气降水同位素的影响。研究表明:西安地区不同季节降水的影响因子的侧重点不同,大气降水的几种效应的影响程度也有差别,对于西安地区以及所在关中平原地区夏季主要来自太平洋的东南季风以及来自印度洋的西南季风的水汽,从大陆效应因素来看,夏季季风所带的水汽经过多次降水到达关中平原,水汽同位素比值已经十分亏损。

This paper studies the hydrogen and oxygen isotope compositions in precipitation in Xi＇an for eight years, and the meteoric water line is given, which shows that some characteristics in the meteoric water line. The impact on precipitation isotope for the tem- perature and precipitation amount is analyzed. The result shows that the impact factors of precipitation isotope is variational in differ- ent seasons, and the degree of influence for several isotope effects is also various. In summer, the water vapor in Xi＇an and Guanzhong Plains come mainly from the southeast monsoon in the Pacific Ocean and from the southwest monsoon in the India Ocean. The mainland effect shows that the water vapor isotopic ratios has been in loss after the vapor arrives at the Guanzhong Plains through multiple rainfall.