关键环境因子及水汽来源对雾水氢氧稳定同位素组成特征的影响

Impacts of Key Environmental Factors and Water Vapor Sources on the Composition Characteristics of Stable Oxygen and Hydrogen Isotopes in Fog Water

雾降水对山区森林生态系统和农业生态系统具有十分重要的生态意义,稳定同位素法是示踪雾水生态水文过程的有效方法。由于雾水采集与测定困难,环境因子对雾水稳定同位素影响的研究较少。为加强雾水稳定同位素变化及其影响因素的认识,通过对2016年1~4月在哈尼梯田区采集的40个雾水样品的稳定同位素组成及环境因子进行分析,得出以下结论:(1)雾水稳定同位素值的时空变化主要受雾水水汽来源和局地环境条件两个因素影响。(2)雾水存在外来和局地两种不同的水汽来源。(3)温度、露点温度和相对湿度三个环境因子与雾水稳定同位素值存在显著的相关性,是影响雾水稳定同位素变化的关键因子。(4)在全球范围内,还缺乏雾水水汽来源及其对雾水稳定同位素值影响的系统性研究,但现有雾水研究可总结出两个特点:同一水汽来来源雾水稳定同位素值范围相对接近,内陆地区雾水稳定同位素值要比海岸地区偏正。

Fog precipitation is of great ecological significance to the mountain forest ecosystem and agroecosystem,and the stable isotope method is efficient in tracing the eco-hydrological process of fog water.Due to the difficulties in collecting and measuring fog water,there are few studies on the influence of environmental factors on the stable isotopes in fog water.In order to strengthen the understanding of the stable isotope changes in fog water and its influencing factors,this paper analyzed the stable isotope composition and environmental factors of 40 samples collected in Hani rice terrace during January-April in 2016.The results show that:(1)The temporal and spatial variation of stable isotope values of fog water are mainly affected by the water vapor sources and local environmental conditions.(2)There are two different sources of water vapor,including external and local ones.(3)The three environmental factors of temperature,dew point temperature and relative humidity have significant correlations with the stable isotope values of fog water,and also are the key factors affecting the stable isotope variation of fog water.(4)Globally,it is still lack of systematic research on the moisture sources of fog water and its effects on the stable isotope values of fog water.However,the existing fog water studies could be summarized in two characteristics:the range of stable isotope values of fog water from the same moisture source is relatively close;and the stable isotope values of fog water in inland areas are more positive than that in coastal areas.