Long-Term Water Storage Changes of Lake Volta from GRACE and Satellite Altimetry and Connections with Regional Climate
Long-Term Water Storage Changes of Lake Volta from GRACE and Satellite Altimetry and Connections with Regional Climate
复制标题
DOI：
10.3390/rs9080842
复制
发表时间：
2017-08
期刊：
影响因子：
--
通讯作者：
Shengnan Ni;Jianli Chen;C. Wilson;Xiaogong Hu
中科院分区：
文献类型：
--
作者：
Shengnan Ni;Jianli Chen;C. Wilson;Xiaogong Hu
重力恢复与气候试验（GRACE）卫星重力数据提供了陆地储水量在不同时空尺度上变化的定量测度。在这项研究中，我们研究了GRACE对Volta湖地区长期水文特征的定量监测能力。采用主成分分析（PCA）研究TWS长期变化的时空变异性。长期伏特湖蓄水量变化是伏特湖流域长期TWS变化的主要信号。由GRACE导出的TWS变化与全球降水气候中心（GPCC）编制的降水变化在时间和空间上都是相关的，但空间泄漏降低了GRACE估计的幅度，特别是在小区域尺度上。利用约束正演模型，我们成功地消除了GRACE估计中的泄漏误差。经过泄漏校正后，grace得出的Volta湖蓄水量变化在年际和更长时间尺度上与卫星测高的独立估计值非常吻合。这证明了GRACE估算在监测和量化湖泊储水量变化方面的价值，特别是在地形复杂的相对较小的区域。
Satellite gravity data from the Gravity Recovery and Climate Experiment (GRACE) provides a quantitative measure of terrestrial water storage (TWS) change at different temporal and spatial scales. In this study, we investigate the ability of GRACE to quantitatively monitor long-term hydrological characteristics over the Lake Volta region. Principal component analysis (PCA) is employed to study temporal and spatial variability of long-term TWS changes. Long-term Lake Volta water storage change appears to be the dominant long-term TWS change signal in the Volta basin. GRACE-derived TWS changes and precipitation variations compiled by the Global Precipitation Climatology Centre (GPCC) are related both temporally and spatially, but spatial leakage attenuates the magnitude of GRACE estimates, especially at small regional scales. Using constrained forward modeling, we successfully remove leakage error in GRACE estimates. After this leakage correction, GRACE-derived Lake Volta water storage changes agree remarkably well with independent estimates from satellite altimetry at interannual and longer time scales. This demonstrates the value of GRACE estimates to monitor and quantify water storage changes in lakes, especially in relatively small regions with complicated topography.