Time-varying land subsidence detected by radar altimetry: California, Taiwan and north China.
Contemporary applications of radar altimetry include sea-level rise, ocean circulation, marine gravity, and icesheet elevation change. Unlike InSAR and GNSS, which are widely used to map surface deformation, altimetry is neither reliant on highly temporally-correlated ground features nor as limited by the available spatial coverage, and can provide long-term temporal subsidence monitoring capability. Here we use multi-mission radar altimetry with an approximately 23 year data-span to quantify land subsidence in cropland areas. Subsidence rates from TOPEX/POSEIDON, JASON-1, ENVISAT, and JASON-2 during 1992-2015 show time-varying trends with respect to displacement over time in California's San Joaquin Valley and central Taiwan, possibly related to changes in land use, climatic conditions (drought) and regulatory measures affecting groundwater use. Near Hanford, California, subsidence rates reach 18 cm yr(-1) with a cumulative subsidence of 206 cm, which potentially could adversely affect operations of the planned California High-Speed Rail. The maximum subsidence rate in central Taiwan is 8 cm yr(-1). Radar altimetry also reveals time-varying subsidence in the North China Plain consistent with the declines of groundwater storage and existing water infrastructure detected by the Gravity Recovery And Climate Experiment (GRACE) satellites, with rates reaching 20 cm yr(-1) and cumulative subsidence as much as 155 cm.
Department of Civil Engineering, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu, Taiwan.
Cheinway
C
Hwang
Chinese Antarctic Center of Surveying and Mapping, Wuhan University, 129 Luoyu Road, Wuhan 430079, China.
Yuande
Y
Yang
Department of Civil Engineering, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu, Taiwan.
Ricky
R
Kao
Department of Civil Engineering, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu, Taiwan.
Jiancheng
J
Han
State Key Laboratory of Geodesy and Earth Dynamics, Institute of Geodesy &Geophysics, Chinese Academy of Sciences, Wuhan 43077, China.|Division of Geodetic Science, School of Earth Sciences, the Ohio State University, Columbus, OH 43210, USA.
C K
CK
Shum
U.S. Geological Survey, 5957 Lakeside Blvd, Indianapolis, IN 46278, USA.
Devin L
DL
Galloway
U.S. Geological Survey, 6000 J Street, Placer Hall, Sacramento, CA 95819, USA.
Michelle
M
Sneed
Green Environmental Engineering Consultant Co. LTD, Hsinchu, Taiwan.
Wei-Chia
WC
Hung
Department of Civil Engineering, National Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu, Taiwan.
Yung-Sheng
YS
Cheng
Chinese Antarctic Center of Surveying and Mapping, Wuhan University, 129 Luoyu Road, Wuhan 430079, China.
Fei
F
Li