| 干旱内陆河流域降水稳定同位素的时空特征及环境意义 |
| 摘要点击 2282 全文点击 718 投稿时间：2018-10-10 修订日期：2018-12-07 |
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| 中文关键词 干旱区 内陆河流域 大气降水 稳定同位素 环境意义 |
| 英文关键词 arid region inland river basins precipitation stable isotope environmental significance |
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| 中文摘要 |
| 依据石羊河流域武威站（海拔1531 m）、民勤站（海拔1389 m）和西大河（海拔2897 m）于2013年7月至2014年7月一个完整水文年的降水样品和气象数据，分析该流域降水稳定同位素的时空变化和局地大气降水线，讨论降水过程中温度、湿度、降水量、平均水汽压以及相对湿度等环境因素对降水稳定同位素演化的影响.结果表明：①研究时段内降水稳定同位素呈现出显著的季节性变化，冬季和春季较低，夏季和秋季较高；②武威站D-excess月均值低于西大河，除可能具有不同的水汽来源外，也反映了高海拔山地地区更多的受到局地再循环水汽的影响，低海拔平原地区云下二次蒸发更强烈；③流域降水稳定同位素表现出显著的温度效应，在天气尺度上体现出降水量效应，可能是受到淋洗作用或季风环流的影响；④δ18O值与平均相对湿度呈负相关关系，可能是随着降水量与湿度的增加使云下二次蒸发作用减弱. |
| 英文摘要 |
| This study was based on one complete hydrological year sampling of precipitation and meteorological data of the Shiyang River Basin in the Wuwei Station (1531 m a.s.l.), Minqin Station (1389 m a.s.l.), and Xidahe Station(2897 m a.s.l.) from July 2013 to July 2014. This paper aims to analyze temporal and spatial variation of stable isotopes in local precipitation, and discuss the impact of environmental factors during precipitation. The stable isotope evolution correlation with temperature, humidity, precipitation, vapor pressure, and average relative humidity is analyzed. The results show that:①During the study period, the stable isotope of precipitation showed significant seasonal changes, lower in the winter and spring, higher in the summer and autumn;②The monthly average D-excess of Wuwei Station is lower than that of Xidahe Station. In addition to the possibility of different water vapor sources, the high-altitude mountain areas are more affected by local recirculating water vapor, and the secondary evaporation under the clouds in low-altitude plain areas is stronger;③The stable isotope of precipitation in the basin shows a significant temperature effect, and the precipitation effect is reflected on the weather scale, which may be affected by leaching or monsoon circulation;④The δ18O value of precipitation is negatively correlated with the average relative humidity. It may be that the secondary evaporation under the cloud is weakened by the increase of precipitation and humidity. |
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