Elevation-dependent changes in the trend of reference evapotranspiration in the Tibetan Plateau during 1960–2017
Elevation-dependent changes in the trend of reference evapotranspiration in the Tibetan Plateau during 1960–2017
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1960-2017年青藏高原参考蒸散发趋势随海拔的变化
DOI：
10.1002/joc.7964
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Shiqiang Zhang
中科院分区：
文献类型：
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作者：
Yaping Chang;Yongjian Ding;Qiudong Zhao;Jia Qin;Shiqiang Zhang
海拔高度对山区气候变量的时空分布起着重要的调节作用，影响着山区的水分和能量平衡，其中参考蒸散量（ET 0）是一个重要的水文指标。然而，ET 0对气候变化的响应仍然知之甚少，特别是在海拔变化超过4,000 m的青藏高原（TP）。使用TP上82个站的长期（1960-2017年）气象观测数据研究了ET 0随海拔的时空变化。结果表明，年平均ET 0呈不显著的增加趋势。ET 0与海拔高度呈显著负相关（p <0.01）。ET 0的正趋势随海拔升高而降低，而ET 0的负趋势随海拔升高而显著增加（p <0.05）。ET 0的趋势幅度在海拔较高的站点变得较小。敏感性分析表明，ET 0对短波辐射（Rs）最为敏感。此外，温度（T）和风速（U）的敏感性显着降低，而Rs和水汽压亏损（VPD）的敏感性略有增加，海拔。贡献和通径分析表明，VPD的增加是ET 0增加的主要贡献者。海拔高度对ET 0变化的影响主要取决于U和VPD贡献的权衡。U是2，500 m以下ET 0变化的最大贡献因素，而VPD是2，500 m以上ET 0增加的主要贡献因素。该研究揭示了ET 0随海拔高度变化对TP的响应，对高海拔地区水文气象过程具有重要意义。
Elevation plays a crucial role in modulating the spatiotemporal distributions of climatic variables in mountainous regions, which affects water and energy balances, among which reference evapotranspiration (ET0) is a key hydrological indicator. However, the response of ET0 to climate change with elevation continues to be poorly understood, especially in the Tibetan Plateau (TP) which has elevation variations of more than 4,000 m. The spatiotemporal variations of ET0 with elevation were investigated using long‐term (1960–2017) meteorological observations from 82 stations on the TP. The results suggest that the average annual ET0 showed an insignificant increasing trend. A significant negative correlation between ET0 and elevation was found (p < .01). The positive trends of ET0 decreased with elevation, whereas the negative trends of ET0 increased significantly with elevation (p < .05). The magnitude of trends of ET0 becomes smaller at higher‐elevation stations. Sensitivity analysis indicated that ET0 was most sensitive to shortwave radiation (Rs). Moreover, the sensitivities of temperature (T) and wind speed (U) significantly decreased with elevation, whereas those of Rs and vapour pressure deficit (VPD) increased slightly with elevation. The contribution and path analyse indicated that increasing VPD was the dominant contributor to the increase in ET0. The effect of elevation on ET0 variation mainly depended on the tradeoff between the contributions of U and VPD. U was the largest contributing factor for the change in ET0 below 2,500 m, whereas VPD was the primary contributor to the increase in ET0 above 2,500 m. This study provides insights into the response of ET0 to climate change with elevation on the TP, which is of great significance to hydrometeorological processes in high‐altitude regions.