天山地区水汽再循环量化研究

利用传统气候学的Brubaker二元模型和降水同位素平衡模型定量研究了新疆天山地区水汽再循环特征。结果表明:(1)气候学角度,天山地区水汽再循环率为9.32%。当地蒸发的水汽形成的降水量为41.8 mm,外来水汽输送到山区形成的降水量为407.2 mm;(2)同位素水汽氘盈余为精细化的分析水汽再循环提供了新的思路,进一步证实天山地区水汽主要来自于西风带的水汽输送,而乌鲁木齐站平均再循环水汽仅占到8%。随着海拔的增加,水汽再循环率逐渐下降,在海拔2000 m以上的水汽再循环可以忽略不计。在西风带关键水汽输送路径建立降水同位素观测断面,使两种方法相结合,共同研究水汽的来源和路径问题,是下一步需要关注的问题。

Quantifying recycled moisture fraction in precipitation of Tianshan Mountain

Terrestrial moisture recycling by evapotranspiration has recently been recognised as an important source of precipitation that can be characterised by its isotopic composition and water mass balance equation. This study calculated the inter-annual variations in the precipitation recycling ratio on the Tianshan Mountain, Central Asia. In arid and semi-arid regions, the contribution of transpiration by plants to local moisture recycling can be small, so that evaporation by bare soil and surface water bodies dominates. The monthly precipitation recycling ratio reached 8~9.32% using the different methods, respectively. The article includes a discussion of these findings in the context of water cycling in the studied region.