Introduction
Data and methods
In situ groundwater level observations
GRACE-derived groundwater storage anomalies
Land subsidence
Auxiliary data
Results and discussion
Long-term GWS depletion exacerbated by droughts
GWSA | Period | Annual amplitude (mm) | Semi-annual amplitude (mm) | Annual phase (degree) | Semi-annual phase (degree) | Trend (mm/yr) |
---|---|---|---|---|---|---|
In situ | 2005–2013 | 40.6 | 20.4 | 347.9 | 97.9 | −19.2 ± 1.7 |
GRACE | 2005–2013 | 18.4 | 11.1 | 318.1 | 101.9 | −17.7 ± 1.1 |
Sub-regional land subsidence responding to natural and anthropogenic factors
Sub-region | Sub-period | Mean annual P (mm) | Mean annual GW abstraction (mm) | Mean subsidence rate (mm/yr) | GWSA trend (mm/yr) |
---|---|---|---|---|---|
Beijing | 1971–1980 | 577.2 | 131.2 | 42.4 | −36.9 ± 5.1 |
1981–1998 | 575.4 | 159.8 | 15.2 | 3.9 ± 2.8 | |
1999–2012 | 507.1 | 146.7 | 62.6 | −76.1 ± 6.5 | |
1971–2013 | 552.0 | 148.0 | 38.0 | −34.1 ± 2.4 | |
Tianjin | 1971–1985 | 586.7 | 57.7 | 84.8 | −3.1 ± 1.3 |
1986–1989 | 579.9 | 58.6 | 35.6 | – | |
1990–2004 | 523.3 | 60.1 | 14.8 | – | |
2005–2013 | 560.9 | 52.0 | 27.1 | −20.2 ± 2.0 | |
1971–2013 | 558.5 | 57.4 | 42.8 | −7.0 ± 0.4 | |
Hebei | 1971–1990 | 524.5 | 60.1 | 68.9 | −14.7 ± 1.1 |
1991–2004 | 500.9 | 83.2 | 71.2 | −19.8 ± 2.1 | |
2005–2013 | 506.3 | 82.6 | 28.3 | −20.7 ± 3.4 | |
1971–2013 | 513.0 | 72.3 | 61.1 | −15.2 ± 0.6 |