Locally recycled moisture from transpiration and surface evaporation is of great importance in the terrestrial hydrological cycle, especially in the widely distributed oases across arid central Asia. Quantitative assessment of the proportional contribution of recycled moisture to local precipitation, i.e., the recycling ratio, is useful to understand the land-air interaction as well as the anthropogenic impact on the regional water cycle. Here we analyzed the stable hydrogen and oxygen isotopes in precipitation samples collected at six stations across the Kaxgar-Yarkant Oasis in the western Tarim Basin of central Asia from April 2018 to June 2020. Using this data, the moisture recycling ratio in this typical oasis was assessed using a Bayesian three-component isotopic mixing model. For the plain stations, the annual weighted mean δ¹⁸O value in precipitation ranged from −5.94 ‰ to −1.46 ‰, and the mountain station has a lower annual mean precipitation isotopic ratio. The average recycling ratio during the summer months ranged between 17.0 % and 63.9 % for each sampling station in the Kaxgar-Yarkant Oasis, and the proportional contribution from transpiration ranged from 15.1 % to 61.3 %. The contribution of plant transpiration to local precipitation is much larger than that of surface evaporation. The recycled portion in total precipitation amount may increase the local precipitation under an oasis expansion background but is insufficient to change the arid background. In addition, the Bayesian isotopic mixing model is promising to determine the recycling ratio in an arid setting, and provides more spatial details than the climate reanalysis-based calculation.

来自蒸腾和地表蒸发的局部循环水分在陆地水文循环中非常重要，特别是在干旱中亚广泛分布的绿洲中。定量评估再循环水分对局部降水的比例贡献，即再循环比，有助于了解陆气相互作用以及人为对区域水循环的影响。在这里，我们分析了 2018 年 4 月至 2020 年 6 月在中亚塔里木盆地西部 Kaxgar-Yarkant 绿洲的六个站点采集的降水样本中的稳定氢和氧同位素。利用这些数据，这个典型绿洲的水分循环比为使用贝叶斯三组分同位素混合模型进行评估。对于平原站，年加权平均δ ¹⁸降水中O值介于-5.94‰～-1.46‰之间，山区站年平均降水同位素比值较低。Kaxgar-Yarkant 绿洲每个采样站的夏季平均回收率在 17.0% 到 63.9% 之间，蒸腾作用的比例贡献在 15.1% 到 61.3% 之间。植物蒸腾对局部降水的贡献远大于地表蒸发。总降水量中的循环部分在绿洲扩张背景下可能会增加局部降水，但不足以改变干旱背景。此外，贝叶斯同位素混合模型有望确定干旱环境中的再循环率，并提供比基于气候再分析的计算更多的空间细节。