Huang Liangke, Wang Zhuohao, Zhang Tengxu, Yao Chaolong, Li Haojun, Liu Lilong
College of Geomatics and Geoinformation, Guilin University of Technology, Guilin 541004, China; Guangxi Key Laboratory of Spatial Information and Geomatics, Guilin, China.
College of Geomatics and Geoinformation, Guilin University of Technology, Guilin 541004, China.
Sci Total Environ. 2024 Jul 10;933:173189. doi: 10.1016/j.scitotenv.2024.173189. Epub 2024 May 11.
The variation of solid Earth's hydrologic loading could cause the elastic vertical deformation of the crust, and the Global Navigation Satellite System (GNSS) could effectively monitor the vertical displacement of surface loads. However, the widely used Green's function method does not work well in areas where GNSS sites are sparse. Here, the vertical displacement time series of GNSS stations and the Slepian basis function method have been applied to convert displacement signals into spatial spectrum signals. The elastic mass load theory is used to study the changes in terrestrial water storage on the Northeastern Tibetan Plateau (NETP). The temporal and spatial characteristics of seasonal water changes are well-represented by the GNSS, the Gravity Recovery and Climate Experiment (GRACE), and the Global Land Data Assimilation System (GLDAS). Several data points suggest that the change in water storage shows a gradual increase from the northeast to the southwest. The greatest annual amplitude of water storage retrieved by GNSS is ∼159 mm, which is greater than the ∼47 mm and ∼44 mm obtained by GRACE and GLDAS. These results demonstrate that GNSS is capable of capturing small-scale hydrological changes in this region, whereas GRACE and GLDAS data tend to underestimate seasonal variations in water storage. We also used GNSS to describe the hydrological drought conditions in NETP, showing that GNSS could be used as an independent method to characterize hydrological drought events. The findings suggest it could observe water storage with high spatial and temporal resolution and aid in comprehending regional hydrological trends with a sparse GNSS station network.
固体地球的水文负荷变化会导致地壳的弹性垂直形变，而全球导航卫星系统（GNSS）能够有效监测地表负荷的垂直位移。然而，广泛使用的格林函数法在GNSS站点稀疏的地区效果不佳。在此，已应用GNSS站的垂直位移时间序列和斯莱皮恩基函数法将位移信号转换为空间频谱信号。利用弹性质量负荷理论研究青藏高原东北部（NETP）的陆地水储量变化。GNSS、重力恢复与气候实验（GRACE）以及全球陆地数据同化系统（GLDAS）很好地呈现了季节性水变化的时空特征。几个数据点表明，水储量变化呈现出从东北向西南逐渐增加的趋势。GNSS反演得到的最大年水储量振幅约为159毫米，大于GRACE和GLDAS得到的约47毫米和44毫米。这些结果表明，GNSS能够捕捉该地区的小尺度水文变化，而GRACE和GLDAS数据往往低估了水储量的季节性变化。我们还利用GNSS描述了NETP的水文干旱状况，表明GNSS可作为表征水文干旱事件的独立方法。研究结果表明，它能够以高时空分辨率观测水储量，并有助于通过稀疏的GNSS站网理解区域水文趋势。
