Water Storage Changes in Three Gorges Water Systems Area Inferred from Grace Time‐Variable Gravity Data

Abstract

Twenty‐two monthly water storage changes are predicted for the supply water systems of the Three Gorges reservoir from GRACE time‐variable gravity data. In order to assess the results, the CPC hydrological models are used to establish two benchmarks. It is found that the results are very reasonable in this area. For Gaussian averaging for 1000 km radius, the total water storage changes in the area have a peak‐to‐peak value of 14 cm, and the annual component has an amplitude of 5.8 cm and a phase of –40.8 days. The RMS difference compared with the inversion results with the same averaging radius using the synthetic gravity data from the CPC models is 1.3 cm for the total water storage changes, and the differences are 0.1 cm and 1.0 day for the amplitude and phase of the annual component. However, for checking the ability of GRACE to monitor the true water storage changes within the area, it is also necessary to compare the inversion results from GRACE gravity models with the true average results of CPC models. For this comparison the RMS difference is 2.1 cm for the total water storage changes, and the differences are 1.7 cm and 9.3 days for the amplitude and phase of the annual component. Consequently, it is found that the first comparison has overestimated the effectiveness of GRACE. Nevertheless, the second comparison shows that the monthly water storage changes can be roughly determined from GRACE data in this area.

The potential of GRACE gravimetry to detect the heavy rainfall‐induced impoundment of a small reservoir in the upper Yellow River

“…As the largest hydroelectric power station in the world, with a capacity of 39.3 km 3 , the Three Gorges Reservoir (TGR), located in the middle main stem of the Yangtze River, is the only reservoir that has been studied using GRACE observations to date [ Wang et al ., ]. Here we will investigate the potential of applying GRACE measurements to detect the hydrologic regime of another reservoir with a much smaller size, namely, the Longyangxia Reservoir (LR).…”

Gravity Recovery and Climate Experiment (GRACE) detection of water storage changes in the Three Gorges Reservoir of China and comparison with in situ measurements

“… Boy and Chao [2002] even simulate the gravity changes related to different stages of the TGR water impoundment. Wang et al [2007] use GRACE data to study the water storage changes for the upstream contributing areas of the TGR and compare to a hydrological model simulation. They conclude that the monthly water storage changes in these areas can be roughly determined from GRACE data, but they did not discuss the gravity and water storage changes caused by TGR water impoundment.…”

Effects of the Tibetan Plateau Crustal Structure on the Inversion of Water Trend Rates Using Simulated GRACE/GPS Data

“…, Farrell 1972;Han and Wahr 1995;Wang et al 1996;Guo et al 2001;Van Dam et al 2002) in nearly all the related studies (e.g., Wang et al 2007;Matsuo and Heki 2010;Jacob et al 2012) because it gives a globally averaged elastic structure. However, the crustal elastic structure in the Crust2.0 model (Laske et al 2011) which has a higher depth resolution is markedly different from that given by PREM.…”

“…Since the launch of the twin-satellites of Gravity Recovery and Climate Experiment (GRACE) in 2002, the Earth's time-varying gravity changes can be precisely monitored on a global scale and the data are successfully used to estimate, based on the method outlined by Wahr et al (1998), water storage changes and trends both on land (e.g., Tibetan Plateau, Yangtze River watershed, Ganges River, Amazon basin, Congo Basin, polar areas) and ocean areas at about 300 -400 km resolution (e.g., Tapley et al 2004;Wang et al 2007;Chen et al 2009;Leuliette and Miller 2009;Rodell et al 2009;Matsuo and Heki 2010). In this regard, it is well known that the gravity changes observed by GRACE are not only due to the direct attraction from surface mass changes but also from internal mass redistribution induced by the elastic loading of surface loads.…”