Energy Geosciences Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California, 94720, USA.
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA.
Sci Rep. 2019 Nov 5;9(1):16053. doi: 10.1038/s41598-019-52371-7.
Range change data, obtained from Synthetic Aperture Radar satellites, form the basis for estimates of aquifer volume change in California's Central Valley. The estimation algorithm incorporates a function penalizing changes far from known well locations, linking the aquifer volume changes to agricultural, industrial, and municipal pumping within the Tulare basin. We show that the range changes are compatible with the hypothesis that the source of aquifer volume changes are variations in effective pressure around documented wells. Specifically, inclusion of the well distance penalty does not degrade the fit to the observations, inversions with and without it both give variance reductions of 99.6%. The patterns of aquifer volume change vary significantly from the drought year, between October 2015 and October 2016, to a wet year in 2017, and into 2018, a year with near average rainfall. The 2.3 million acre-feet of estimated volume reduction, a lower bound on the amount of water extracted from the basin between October 2015 and 2016, agrees with independent estimates of 1.8 and 2.3 million acre-feet. The aquifer volume reduction is also compatible with a loss of 3.1 km (2.5 million acre-feet) in groundwater volume derived from Gravity Recovery and Climate Experiment (GRACE) satellite data.
从合成孔径雷达卫星获得的范围变化数据是估算加利福尼亚中央谷地含水层体积变化的基础。该估算算法包含一个惩罚远离已知水井位置变化的函数，将含水层体积变化与图莱里盆地内的农业、工业和市政抽汲联系起来。我们表明，范围变化与含水层体积变化的来源是记录在案的水井周围有效压力变化的假设是一致的。具体来说，包含井距惩罚并不会降低对观测结果的拟合程度，有和没有它的反演都能将方差降低 99.6%。含水层体积变化的模式与干旱年份（2015 年 10 月至 2016 年 10 月）到湿润年份（2017 年）以及 2018 年（降雨量接近平均水平）显著不同。估计的 230 万英亩英尺的体积减少量是 2015 年 10 月至 2016 年期间从盆地中抽取的水量的下限，与独立估计的 180 万英亩英尺和 230 万英亩英尺一致。含水层体积的减少也与源自重力恢复和气候实验（GRACE）卫星数据的 310 立方千米（250 万英亩英尺）地下水体积的损失相符。
