哈尼梯田麻栗寨河流域雨季大气降水氢氧同位素特征及影响因素

Hydrogen and oxygen isotopic of precipitation during the rainy season of the Malizhai River basin in Hani terraces:characteristics and impact factors

以红河哈尼梯田文化景观遗产核心区麻栗寨河流域的雨季大气降水为研究对象,对2014年雨季典型月7月的氢氧同位素组成进行了分析,拟合出大气瞬时降水线方程,并与邻近地区及全国、全球降水线方程进行对比,分析温度、湿度、降水量等气象参数和海拔对氢氧稳定同位素的影响,并初步判断该区的水汽来源.结果表明:(1)研究区雨季大气降水δ18O值变化范围大,与邻近的昆明、贵阳、成都地区相比,贫化明显;(2)大气降水线方程为δD=7.59δ18O+3.31,其斜率和截距较小,说明研究区雨季降水量大且蒸发强烈、降水的水汽来源非单一化,除受印度洋、孟加拉湾的变热性热带海洋气团的影响,还受研究区地表水体的二次蒸发影响;(3)研究区降水稳定同位素特征显示不但存在明显的降水量效应,也存在温度效应和海拔效应,但各因素是综合作用的,主导因素不明显.

Precipitation during the rainy season over the Malizhai River basin at the cultural landscape heritage core area of the Honghe Hani rice terraces was taken as the object to analyze its hydrogen and oxygen isotopic compositions and then to put forward an atmospheric precipitation equation to describe its characteristics through comparison with those in neighbor areas, in China as a whole and in the globe. The effects of meteorological parameters including temperature, humidity, precipitation and elevation also analyzed to judge the vapor sources. The results indicate： （1） δ18O in precipitation in rainy season has a large changing range and an obvious isotopic depletion. （2） The local meteoric water line is δD=7.59δ18O＋3.31, with less slope and intercept, showing large amount of precipitation and a strong evaporation, with multi-vapor sources not only from the hot tropical marine air mass of India Ocean and Bengal Bay, but also from the second evaporation of surface water at the local scale. （3） There are obvious isotopic effects of precipitation, temperature and altitude in the study area, characterized by comprehensive impact without obvious leading factor.