Abstract Moisture sources affect the temporal variations of the elevation effects on the stable isotopes in monsoon precipitation. However, whether it will lead to spatial variations and form a specific spatial-temporal heterogeneity pattern remains to be explored. Based on the monthly precipitation samples collected in Ailao Mountains of East Asian monsoon region, we computed and identified five moisture source regions to facilitate its comparison to the monthly oxygen isotope composition (δ18O) of precipitation with HYSPLIT model. We analysed the influence mechanisms of the moisture sources on the temporal and spatial heterogeneity of the elevation effect on the hydrogen and oxygen stable isotopes during dry and rainy seasons. We found that the temporal heterogeneity of the elevation effects on the precipitation 18O depends on the proportion of the moisture sources in the dominant direction, and as the proportion increases, the elevation effect becomes more significant. The spatial heterogeneity depends on the combination complexity of the moisture sources, the simpler the combinations, the more significant the elevation effects. The results demonstrate that for precipitation δ18O in Ailao Mountains, the dominant of monsoon moisture sources (the ratio higher than 50%) can result in significant elevation effects, while the mixtures of multiple moisture sources and the dominant of local moisture sources will lead to no elevation effects. Future studies should pay more attention to the influence mechanism of the spatial and temporal heterogeneity of the elevation effects on a relatively larger or global scale.

中文翻译：

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水分来源对季风降水同位素海拔效应时空异质性的影响

摘要 水分来源影响季风降水稳定同位素海拔效应的时间变化。然而，它是否会导致空间变化并形成特定的时空异质性模式仍有待探索。基于东亚季风区哀牢山月降水样本，我们计算并确定了五个水分源区，以方便其与HYSPLIT模型的降水月氧同位素组成（δ18O）进行比较。我们分析了水分来源对旱季和雨季氢氧稳定同位素海拔效应时空异质性的影响机制。我们发现高程对降水 18O 影响的时间非均质性取决于主导方向水分来源的比例，随着比例的增加，高程效应变得更加显着。空间异质性取决于水分源组合的复杂程度，组合越简单，高程效应越显着。结果表明，哀牢山降水δ18O中，季风湿源占优势（比例高于50%）可导致显着的海拔效应，而多种湿源混合和局地湿源占优势将导致无海拔效应。