| 摘要: |
| 【目的】准确量化生态系统的干旱敏感性程度，为生态干旱早期预警和减少生态损失提供参考。【方法】以中国西北地区为例，基于生态缺水量构建标准化生态干旱指数（standardized ecological water deficit index,SEWDI），结合植被水分利用效率（water use efficiency,WUE）定义生态干旱敏感性；采用Copula方法探讨生态干旱加剧条件下WUE升高的概率，以此分析生态干旱的敏感性。【结果】塔里木盆地、昆仑山脉、吐鲁番盆地以及柴达木盆地、河西走廊等地植被生态缺水量较高，逐月均值最高达75 mm。在研究区大部分区域SEWDI与WUE相关性较强，其中显著正相关区域占全区的24.2%，主要分布于新疆大部、青海西部、陕西南部等地；显著负相关区域占全区的36.8%，主要分布于黄土高原等地；随着生态干旱的加剧，WUE对生态干旱的敏感性在不同地区并非单调增加。植被生长期内生态干旱的敏感性随着干旱胁迫程度加剧而升高，且草地的生态干旱敏感性高于林地和耕地。5-6月WUE升高概率上升的速率最快，轻旱-中旱、中旱-重旱、重旱-特旱3个干旱变化情况下，WUE升高概率的月平均速率分别为0.09，0.07和0.06。【结论】水分利用效率（WUE）可以很好地反映植被在生长期遭受干旱胁迫时的生态干旱敏感性，可用作表征生态干旱敏感性的因子。 |
| 关键词: 生态干旱 干旱敏感性 水分利用效率 条件概率 西北地区 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金项目(52079111) |
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| Assessment of ecological drought sensitivity based on water use efficiency |
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LIU Xuan,SU Xiaoling,JIANG Tianliang,et al
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| Abstract: |
| 【Objective】This study accurately quantified the degree of drought sensitivity of ecosystems to provide reference for early warning of ecological drought and reduction of ecological losses.【Method】The standardized ecological water deficit index (SEWDI) was constructed based on the ecological water deficit in Northwest China,and the ecological drought sensitivity was defined by combining water use efficiency (WUE) of vegetation.The Copula method was used to analyze the sensitivity of ecological drought by exploring the probability of WUE increase under the condition of increasing ecological drought.【Result】The ecological water deficit of vegetation in the Tarim Basin,Kunlun Mountains,Turpan Basin,Qaidam Basin and Hexi Corridor was high,with the highest monthly mean value of 75 mm.SEWDI was strongly correlated with WUE in most regions and areas with significantly positive correlation accounted for 24.2% of the total region,mainly in Xinjiang,western Qinghai and southern Shaanxi.The areas with significantly negative correlation accounted for 36.8% of the total region,mainly in the Loess Plateau.With the intensification of ecological drought,the sensitivity of WUE to ecological drought was not monotonically increased in different regions.The sensitivity of WUE to ecological drought increased with the increase of drought stress during the vegetation growth period,and the sensitivity of ecological drought in grassland was higher than that in forest land and cropland.The rate of increase in WUE probability from May to June was the fastest,and the monthly average rates of increase in WUE probability in the conditions of light drought moderate drought,moderate droughtsevere drought and severe drought extreme drought were 0.09,0.07,and 0.06,respectively.【Conclusion】WUE can well reflect the ecological drought sensitivity of vegetation under drought stress during the growing period and can be used as a factor to characterize ecological drought sensitivity. |
| Key words: ecological drought drought sensitivity water use efficiency conditional probability Northwest region |
