# Groundwater Storage Changes in China from Satellite Gravity: An Overview
## 3 Results
### Song-Liao Basin  
Song-Liao Basin, located in the northeast of China, includes the plain regions of the Songhua River Basin and the Liaohe River Basin (LRB) (Figure 1). In this study, we focus on the GWS changes in the LRB considering the significant GWS depletion and the availability of ground well observations in this region. The LRB is an important grain-production and heavy-industry base in China, covering an area of 260,000 km\({}^{2}\). Due to the rapid development of agriculture, industrialization, and urbanization and consequent severe surface water pollution, groundwater has become a major source of water resources utilization in the LRB [92; 93; 94]. About 60% of water consumption in the LRB is from groundwater in  
Figure 5: (**a**) Time series of GWS changes in the NCP from GRACE, in situ observations, WGHM and PCR-GLOBWB from 2002 to 2014. Shaded areas are estimated uncertainties in GRACE-derived GWS changes. (**b**) Annual precipitation anomalies and PDSI values in the NCP from 2002 to 2014.  
the past decade [66]. Long-term dry conditions and extensive groundwater mining for agricultural, industrial and domestic consumption result in significant groundwater declines in the LRB in the past two decades [94]. Based on GRACE data, [PERSON] et al. [95] found a GWS decline rate of 13.5 \(\pm\) 1.9 mm/yr from 2003 to 2010 and the largest GWS depletion rate of 26 mm/yr for 2005-2009 in Horqin Sandy Land, i.e., the upstream of the Liaohe River including Tongliao City, which is consistent with limited six monitoring well observations they collected from the CIGEM. [PERSON] et al. [46] found a GWS decline rate of 6.8 \(\pm\) 3.6 mm/yr during 2005-2011 in the western LRB using GRACE. In the spatial domain, GRACE detects large-scale GWS depletion over the LRB during 2005-2009 (Figure 6b). WGHM shows significant GWS depletion near Tongliao and Shenyang; while PCR-GLOBWB highlights the mass loss near Tongliao and Chifeng (Figure 6c,d). For temporal variability in GWS, GRACE observes obvious interannual GWS variations during 2002-2014 (Figure 7a). GRACE-derived GWS increased during 2002-2005, followed by a significant GWS decline from 2005 to 2009 at a rate of \(-\)5.0 \(\pm\) 1.2 km\({}^{3}\)/yr (Table 1), and then groundwater recovered again since 2010. GWS results from well observations also show a similar GWS declining rate in 2005-2009 (\(-\)5.1 \(\pm\) 0.5 km\({}^{3}\)/yr, Table 1) and a GWS increase in 2010-2013, consistent with GRACE results. PCR-GLOBWB, however, only indicates a long-term GWS declining rate, similar to its estimates in the NCP. Figure 6: **(a)** Topography of the LRB and its surroundings. The red boundary outlines the basin. The white line shows the boundary of the Song-Liao Basin, same as Figure 1. Locations of three main cities in the LRB, i.e., Shenyang, Chifeng, and Tongliao, are also shown. GWS rates from **(b)** GRACE, **(c)** WGHM and **(d)** PCR-GLOBWB in the LRB and its surroundings during 2005–2009. Different from PCR-GLOBWB, changes in GWS from WGHM show similar interannual fluctuations as results from GRACE and well observations, but with significantly smaller magnitude \begin{table}
\begin{tabular}{c c c} \hline \hline
**GWS Rates** & **2005–2009** & **2002–2014** \\ \hline GRACE & \(-5.0\pm 1.2\) & \(-0.5\pm 0.5\) \\ Well observations & \(-5.1\pm 0.5\) & - \\ PCR-GLOBWB & \(-2.0\pm 0.1\) & \(-1.8\pm 0.1\) \\ WGHM & \(-1.3\pm 0.1\) & \(-0.6\pm 0.1\) \\ Groundwater bulletins & \(-1.1\pm 0.2\) & \(-0.4\pm 0.1\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: GWS rates (km\({}^{3}\)/yr) in the LRB based on GRACE, well observations, HMs and groundwater bulletins for 2005–2009 and 2002–2014. Figure 7: **(a)** Time series of GWS changes in the LRB from GRACE, PCR-GLOBWB and well observations from 2002 to 2014. Shaded areas are estimated uncertainties in GRACE-derived GWS changes; **(b)** Same as **(a)**, but from WGHM and groundwater bulletins; **(c)** Annual precipitation anomalies and PDSI values in the LRB from 2002 to 2014. (Figure 7b).