基于GRACE数据的中国地下水储量时空变化研究

Spatio-temporal Variation of Groundwater Reserves in China Based on GRACE Data

研究中国长时间序列地下水储量变化,识别地下水储量下降区域及该区域人口暴露情况,为水资源可持续利用提供重要的科学参考。利用GRACE(重力恢复和气候实验)卫星数据和GLDAS(全球陆地数据同化系统)数据,根据水量平衡原理分析了2003-2020年中国地下水时空变化特征。结果表明:(1)中国地下水的丰水区主要分布在长江流域以南和青藏高原区,缺水区主要分布在华北地区与西北地区;中国地下水稳定性存在显著的空间差异,华北地区、西北地区和青藏高原区的稳定级别为差;(2)中国地下水等效水高在2003-2020年呈下降趋势,贡献区域主要集中在北方区域;多年平均等效水高为-10.91 mm/a,整体以减少为主;地下水等效水高由2003年的-0.83 mm下降至2020年-39.55 mm,18年间共下降38.72 mm,下降率为2.15 mm/a;(3)人水矛盾突出区域主要集中在华北平原,空间上南方区域比北方更安全。2020年中国市域地下水下降暴露人口平均>500人/km^(2)的区域集中分布在华北平原及周边区域,暴露总量最高的3个行政区为北京、天津、保定。

Studying the long-term changes in groundwater storage and identifying the regions where groundwater storage has declined,as well as the population exposure density in these regions,can provide important scientific references for the sustainable utilization of water resources.Based on the Gravity Re-covery and Climate Experiment(GRACE)satellite data,LandScan remote sensing images and Global Land Data Assimilation System(GLDAS)data,we explored the temporal and spatial variation of ground-water in China during the period 2003-2020 based on the principle of water balance.Results show:(1)The areas with abundant groundwater in China are mainly located in the south Yangtze River basin and the Qinghai-Tibet Plateau,while groundwater-deficient areas are mainly in North and Northwest China.There are significant spatial differences in groundwater stability in China,and the stability in North Chi-na,Northwest China and the Qinghai-Tibet Plateau are poor.(2)The average equivalent water height from 2003 to 2020 was-10.91 mm/a,and the equivalent water height of groundwater in China de-creased from 2003 to 2020,mainly in northern China.The equivalent groundwater level decreased from-0.83 in 2003 to-39.55 mm in 2020,a total decrease of 38.72 mm in 18 years,with an average annual decrease of 2.15 mm/a.(3)The contradiction between human need and water supply was most prominent in the North China Plain,and groundwater in the southern region was more secure.In 2020,the areas with an average population>500 people/km^(2) exposed to groundwater decline was primarily in the North China Plain and surrounding areas,and the three most serious administrative regions were Beijing,Tianjin and Baoding Cities.