Abstract:

Serious shortage of water resources has become a bottleneck that restricts the coordinated development of Beijing-Tianjin-Hebei. Clarifying the temporal and spatial variations of long-term surface water and their influencing factors are of great significance for the rational allocation of water resources and the construction of coordinated ecological security pattern in this region. Based on the Google Earth Engine (GEE) cloud platform, this study comprehensively utilized multi-index water body detection rules, linear slope, multiple linear regression and partial differential decomposition methods to construct a continuous change map of surface water with high spatial and temporal resolution in the Beijing-Tianjin-Hebei region. The spatial and temporal variations of surface water in the study area and four typical areas, i.e., Angulinao, Miyun Reservoir, Baiyangdian and Beidagang Wetlands, were revealed, and the impacts of precipitation, temperature, potential evapotranspiration, and water area in the previous year, human production and living water, and residual factors (e.g., water diversion measures) on surface water changes were determined. The results show that (1) from 1985 to 2021, the water area in the Beijing-Tianjin-Hebei region showed a trend of increasing first and then decreasing. The net increment of permanent water area was 122.85 km², and the net increment of temporary water area was 1788.95 km². The water area of Angulinao and Baiyangdian showed a decreasing trend, while the water area of Miyun Reservoir and Beidagang Wetland showed an increasing trend. (2) The spatial distribution characteristics of surface water in the Beijing-Tianjin-Hebei region as a whole showed that the surface water resources in the eastern coastal and central regions were rich, while the northern and southern regions were relatively scarce. The four typical areas had large water conversion and strong spatial heterogeneity. (3) Precipitation, water area in the previous year and water diversion (residual factors) had positive effects on surface water changes in the Beijing-Tianjin-Hebei region, while temperature, potential evapotranspiration, agricultural water, industrial water, and domestic water all showed negative effects. The influence of non-meteorological factors was greater than meteorological factors. The reduction of water area in Angulinao and Baiyangdian was mainly affected by agricultural water and water conservancy project constructions (residual factors).

Key words: Google Earth Engine, surface water changes, temporary water, permanent water, influencing factors, Beijing-Tianjin-Hebei region

摘要：

京津冀地区水资源严重短缺，已成为制约京津冀协同发展的瓶颈。明晰长时序地表水体时空变化特征及其影响因素，对该区域的水资源合理配置及构建协同发展生态安全格局具有重要意义。基于Google Earth Engine（GEE）云平台，综合利用多指数水体检测规则、线性斜率、多元线性回归和偏微分分解等方法，构建了京津冀地表水体高时空分辨率连续变化图谱，揭示了研究区及安固里淖、密云水库、白洋淀和北大港湿地4个典型区的地表水体时空分异规律，厘定了降水量、气温、潜在蒸散发、前一年水体面积、人类生产生活用水和和引水调水等因素对地表水体变化的影响量。结果表明，（1）1985-2021年京津冀地区水体面积整体呈先增加后减少趋势，永久性水体面积净增122.85 km²，季节性水体面积净增1788.95 km²。其中安固里淖和白洋淀水体面积呈减少趋势，密云水库和北大港湿地水体面积呈增加趋势。（2）京津冀地表水体空间分布特征整体表现为东部沿海和中部地区地表水资源较丰富，北部和南部地区相对匮乏，4个典型区水体转换幅度大，具有较强的空间异质性。（3）降水量、前一年水体面积、引水调水（其他因素）对京津冀地表水体变化起正向影响，气温、潜在蒸散发、农业用水、工业用水和生活用水均起负向影响作用，且非气象因素的影响作用整体大于气象因素，其中安固里淖和白洋淀水体面积减少主要受农业用水和水利工程建设等因素的负向影响。

关键词: 谷歌地球引擎, 地表水体变化, 季节性水体, 永久性水体, 影响因素, 京津冀地区