Determination of Weak Terrestrial Water Storage Changes from GRACE in the Interior of the Tibetan Plateau
Determination of Weak Terrestrial Water Storage Changes from GRACE in the Interior of the Tibetan Plateau
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DOI：
10.3390/rs14030544
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发表时间：
2022-01
期刊：
影响因子：
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通讯作者：
L. Xiang;Hansheng Wang;H. Steffen;Baojin Qiao;W. Feng;L. Jia;P. Gao
中科院分区：
文献类型：
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作者：
L. Xiang;Hansheng Wang;H. Steffen;Baojin Qiao;W. Feng;L. Jia;P. Gao
重力恢复和气候实验（GRACE）卫星任务的时间序列已成功用于揭示世界许多地区陆地水储存（TWS）的变化。这在青藏高原内部受到阻碍，因为派生的 TWS 变化对不同可用 GRACE 解决方案的选择非常敏感，并且过滤器可以去除观测中的南北向 (N-S) 条纹特征。这导致了之前研究中 TWS 变化的分布存在争议。在本文中，我们生成了 2003 年至 2009 年青藏高原 TWS 变化的聚合水文信号 (AHS)，并测试了大量 GRACE 解决方案-过滤器组合和 mascon 模型，以确定过滤结果与我们的 AHS 匹配的最佳组合或 mascon 模型。我们发现去条带滤波器的应用对于消除显示为 N-S 条带的相关错误是必不可少的。确定了三种性能最佳的去条带过滤器，并与两种性能最佳的解决方案相结合，它们代表了 GRACE 确定青藏高原内部弱陆地水储存变化的最可靠的解决方案-过滤器组合。反过来，超过 100 个其他经过测试的解决方案-过滤器组合和 mascon 解决方案导致高原内外 TWS 变化的分布非常不同，这在一定程度上与 AHS 不一致。这主要是由于对N-S条纹噪声的抑制效果较差。我们的结果还表明，对于 GRACE 球谐解，最有效的去条纹是在最大次数和 60 阶内执行的。当应用半径为 340 公里的高斯滤波器进行附加平滑时，高原内部的结果显示 TWS 趋势中存在一个异常现象。我们建议使用我们确定的最佳解决方案-滤波器组合来确定2002年至2017年整个GRACE运行期间以及后续GRACE-FO任务期间青藏高原及邻近地区的TWS变化。
Time series of the Gravity Recovery and Climate Experiment (GRACE) satellite mission have been successfully used to reveal changes in terrestrial water storage (TWS) in many parts of the world. This has been hindered in the interior of the Tibetan Plateau since the derived TWS changes there are very sensitive to the selections of different available GRACE solutions, and filters to remove north-south-oriented (N-S) stripe features in the observations. This has resulted in controversial distributions of the TWS changes in previous studies. In this paper, we produce aggregated hydrology signals (AHS) of TWS changes from 2003 to 2009 in the Tibetan Plateau and test a large set of GRACE solution-filter combinations and mascon models to identify the best combination or mascon model whose filtered results match our AHS. We find that the application of a destriping filter is indispensable to remove correlated errors shown as N-S stripes. Three best-performing destriping filters are identified and, combined with two best-performing solutions, they represent the most reliable solution-filter combinations for determination of weak terrestrial water storage changes in the interior of the Tibetan Plateau from GRACE. In turn, more than 100 other tested solution-filter combinations and mascon solutions lead to very different distributions of the TWS changes inside and outside the plateau that partly disagree largely with the AHS. This is mainly attributed to less effective suppression of N-S stripe noises. Our results also show that the most effective destriping is performed within a maximum degree and order of 60 for GRACE spherical harmonic solutions. The results inside the plateau show one single anomaly in the TWS trend when additional smoothing with a 340-km-radius Gaussian filter is applied. We suggest using our identified best solution-filter combinations for the determination of TWS changes in the Tibetan Plateau and adjacent areas during the whole GRACE operation time span from 2002 to 2017 as well as the succeeding GRACE-FO mission.