多尺度视角下的青藏高原水资源短缺估算及空间格局

青藏高原水资源总量丰富,但由于水资源量与用水量在空间上分布不均衡,部分人口、城镇密集地区水资源短缺严重。本研究在多源数据的基础上,通过空间分析、降尺度处理等,建立了青藏高原省区、市域、县域空间尺度的水资源与用水量数据集。通过比较5、10、20、30年重现期多空间尺度的水资源短缺程度,分析水资源短缺在青藏高原的尺度效应,揭示青藏高原水资源短缺格局与特征,识别面临水资源短缺的人口与面积。结果表明,青藏高原在省区尺度无水资源短缺;在15个市域单元中,有3个市域出现水资源短缺;在115个县域单元中,有29个县域呈现出不同程度的水资源短缺,水资源短缺县域主要集中在青海省的河湟谷地、柴达木盆地与西藏自治区的一江两河流域等人口、城镇密集区域。总体而言,由于较大空间尺度地理单元内部各县域用水强度差异,在县域尺度面临水资源短缺的人口与面积大于市域与省区尺度面临水资源短缺的人口与面积。以县域为基本单元,发现青海省与西藏自治区30年重现期面临水资源短缺的人口占总人口的56.4%,出现水资源短缺的面积占总面积的10.4%。县域之间水资源短缺指数秩相关系数计算结果显示,省区内部各县域同时出现水资源短缺的可能性较大,而省区之间各县域同时出现水资源短缺的可能性相对随机。研究结果为制定青藏高原水资源短缺管理对策、促进区域城镇化与资源环境协调发展提供科学依据。

A Multi-scale Perspective on Water Scarcity Assessment in the Tibetan Plateau

The total water resource in the Tibetan plateau is abundant. However, some areas within the plateau are faced with severe water scarcity due to the spatial mismatch between available water resources and demands of population and industries. In this study, multiple sources of data were used to evaluate water supply and demand relationships in Qinghai and Tibet. Water scarcity degrees were assessed at the county, prefecture, and province levels in the Tibetan Plateau for 5 year, 10 year, 20 year and 30 year return periods. The effect of spatial scales on water scarcity assessment was analyzed by comparing water scarcity levels based on analyses on different spatial scales. The spatial pattern of water scarcity in the Tibetan Plateau was characterized, and the population and areas that suffered from water scarcity were identified. At the provincial level, no water scarcity occurred in the Tibetan plateau. Three out of 15 prefectures in the Tibetan Plateau were faced with water scarcity. Twenty nine out of 115 counties had water scarcity problems. Water scarce counties were mostly located in relatively highly populated and urbanized areas including River Huang Valley, Qaidam Basin and the basins of Yarlung Zangbo River, Lhasa River and Nianchu River. Overall, the population and areas faced with water scarcity at the county level were larger than at the prefecture and provincial levels. This can be explained by the spatial difference of water uses between counties. At the county level, 56.4% population and 10.4% areas were faced with water scarcity based on 30 years return period. The rank correlation coefficients of water scarcity degrees in different years in water-scarce counties indicate that counties in the same province are likely to experience water scarcity in same periods, while the chance of counties in different provinces experiencing water scarcity in the same year is rather random. Our findings provide useful information for sustainable water resource exploitation toward coordinated urbanization and resources and environmental management in the Tibet Plateau.