By dint of Isotope data of the atmospheric precipitation in Global Network of Isotopes of Zhangye STATION, the changes characteristics of precipitation in Zhangye were analyzed. The analysis of the relationship between δ18O with precipitation and temperature respectively implied that the weighted average of δ180 took on a good “temperature effect”. At the same time, it showed a positive correlation between the weighted average of δ18O and precipitation, which was related to the arid and semi-arid climate of Zhangye. The slope and intercept of local metoorological water line (LMWL) of Zhangye were lower than that of Global meteorological water line (GMWL) and Chinese precipitation line. It was found that the slope of local meteorological water line in autumn and winter was lower than that in spring and summer. The main reason was that local evaporation of water vapor took up a large proportion in spring and summer and the maritime vapor had a major influence in this period of time. Combined environmental isotope data of precipitation with Backwards Trajectory, it showed:1 )Zhangye was dominated by westerly continental vapor throughout the year, and also was influenced by the maritime vapor in spring and summer. 2)Owing to the high temperature, Zhangye was remarkably effected by local evaporation of water vapor in spring and summer.%利用全球同位素监测网(GNIP)张掖站的大气降水环境同位素数据,分析了张掖大气降水中δ18O的变化规律,通过分析其与气温和降水之间的关系,发现δ18O月加权平均值表现出很好的温度效应,且其与降水成正相关关系,这与张掖干旱半干旱气候有关.对张掖大气降水线的研究发现,当地大气降水线(LMWL)比全球降水线(GMWL)及中国降水线的斜率和截距都低.冬秋季降水线的斜率低于春夏季,原因是局地蒸发的水汽在春夏季占有较大的比重,并且受海洋性水汽影响较大.利用降水同位素资料结合后向轨迹法(Backwards Trajectory)对张掖水汽来源进行推断,结果表明,张掖全年以西风带大陆性水汽为主,春夏季还会受到海洋性水汽的影响,同时由于较高的温度,春夏季受局地蒸发性水汽的影响相当明显.
展开▼
