近20年京津冀陆地水储量变化特征及其影响因子分析

Change Characteristics and Influencing Factors of Terrestrial Water Storage in the Beijing-Tianjin-Hebei Region in the Past 20 Years

水资源严重短缺是京津冀地区面临的重要生态环境问题之一,制约着区域协同发展战略的实施。陆地水储量变化深刻影响着水资源的分布和供给,因此,深入认识陆地水储量及其组分的变化特征和原因可以为完善区域水资源管理、实现水资源优化配置提供科学依据,对区域水资源可持续利用具有重要意义。目前,京津冀地区水储量和其组分的变化,以及自然和人为因素的影响特征尚不清楚。本文采用GRACE(Gravity Recovery and Climate Experiment)卫星重力观测数据和全球陆面数据同化系统GLDAS(Global Land Data Assimilation System)数据分析了近20年(2002~2021年)年陆地水储量及其组分的时空变化特征,并结合降水、蒸散发、径流和人类活动用水数据从水循环角度分析了水储量变化的影响因素。结果表明:(1)2002~2021年,北京、天津、河北的陆地水储量(趋势系数分别为-0.71、-0.84、-1.26 cm/a)和地下水储量(趋势系数分别为-1.12、-1.01、-1.55 cm/a)都呈显著减少趋势,而土壤水储量呈现显著增加趋势。(2)北京、天津和河北地下水储量的变化与各自陆地水储量的变化高度一致,相关系数均高达0.8及以上,加之其它分量增加的相反变化趋势,表明地下水储量显著下降是京津冀地区陆地水储量减少的主要原因。(3)3个省/市降水增加对陆地水储量产生正向贡献,蒸散发和径流增加对陆地水储量产生负向贡献。气候/水文因子的综合作用使北京和天津的陆地水储量增加,却造成河北的陆地水储量减少。北京、天津、河北气候变化的贡献率分别为23.60%、33.95%和26.99%,人类活动的贡献率分别为76.40%、66.05%和73.01%,陆地水储量减少主要是人类活动的影响。(4)地下水储量的显著减少是人为活动大量开采地下水的直接结果,表明加强人为用水的管理是京津冀地区水资源可持续利用的关键环节。本文研究结果可为科学掌握京津冀的水储量时空变化规律及影响机制提供数据支撑,为该区域水资源有效管理提供理论依据。

The severe shortage of water resources is a critical ecological and environmental challenge faced by the Beijing–Tianjin–Hebei region,impeding the implementation of regional coordinated development strategies.Terrestrial water storage(TWS)changes profoundly affect the distribution and supply of water resources.Therefore,comprehensively understanding the characteristics and drivers behind TWS and its components is crucial for improving regional water resource management and achieving the optimal allocation of these resources,ultimately supporting sustainable utilization of regional water resources.At present,the changes in water storage and its components and the impact of natural and human factors within the Beijing–Tianjin–Hebei region are insufficiently understood.This paper leverages data from the GRACE(Gravity Recovery and Climate Experiment)and the GLDAS(Global Land Data Assimilation System)to analyze the temporal and spatial change characteristics of TWS and its components over the past 20 years(2002–2021).Additionally,it analyzes the factors influencing water storage changes from a water cycle perspective,incorporating data on precipitation,evapotranspiration,runoff,and human water consumption.The results reveal the following:(1)TWS and groundwater storage in Beijing,Tianjin,and Hebei have exhibited significantly declining trends,with trend coefficients of-0.71,-0.84,and-1.26 cm/a for TWS and-1.12,-1.01,and-1.55 cm/a for groundwater storage,respectively from 2002 to 2021.By contrast,soil water storage presented a notable increasing trend.(2)Groundwater storage changes in Beijing,Tianjin,and Hebei closely align with those of their respective TWS,demonstrating correlation coefficients of 0.8 or higher.In addition,the trends of other components are increasing,which is opposite to the trend of TWS.This indicates that the significant decrease in groundwater storage is the main cause of TWS reduction in the Beijing–Tianjin–Hebei region.(3)Increased precipitation has positively influenced TWS across the three provinces/cities,while the increase in evapotranspiration and runoff levels negatively contributes to TWS.The interplay of climate/hydrological factors has led to TWS gains in Beijing and Tianjin but declines in Hebei.The contribution rates of climate change to TWS changes are 23.60%,33.95%,and 26.99%for Beijing,Tianjin,and Hebei,respectively,while human activities account for 76.40%,66.05%,and 73.01%,respectively.This indicates that TWS declines are mainly influenced by human activities.(4)The significant reduction in groundwater storage directly stems from the massive exploitation of groundwater caused by human activities,highlighting the importance of stringent water use management for sustainable water resource utilization in the Beijing–Tianjin–Hebei region.This research offers valuable data support for scientifically grasping the spatiotemporal changes and impact mechanisms of water reserves in the Beijing–Tianjin–Hebei region,offering a theoretical basis for the effective management of water resources in the region.