Asthenospheric anelasticity effects on ocean tide loading around the East China Sea observed with GPS
Asthenospheric anelasticity effects on ocean tide loading around the East China Sea observed with GPS
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DOI：
10.5194/se-11-185-2020
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发表时间：
2020-02
期刊：
影响因子：
3.4
通讯作者：
Junjie Wang;N. Penna;P. Clarke;M. Bos
中科院分区：
文献类型：
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作者：
Junjie Wang;N. Penna;P. Clarke;M. Bos
摘要。与参考地震地球模型的1 s周期相比，在半日潮期，非弹性可使软流层的剪切模量降低8% - 10%。研究表明，这种非弹性效应可能对东海M2潮期的海潮加载位移有显著影响。通过与潮计观测值的比较，我们确定在DTU10、EOT11a、FES2014b、GOT4.10c、HAMTIDE11a、NAO99b、NAO99Jb、OSU12和TPXO9-Atlas等9个海潮模型中，区域模式NAO99Jb在该区域的精度最高，预测M2垂直海潮加载位移的相关误差为0.2 ~ 0.5 mm。相比之下，使用纯弹性径向初步参考地球模型（PREM）预测的海潮载荷位移，在日本琉球群岛的GPS观测结果的不确定性为0.2-0.3 mm，其90百分位误差为1.3 mm。我们表明，使用基于非弹性prem的地球模型将这90个百分位数的差异减少到0.9毫米。使用由横向变化的S362ANI模式的区域平均值组成的非弹性径向地球模式，将第90百分位数降低到0.7 mm，这与由于海潮模式和GPS观测的不确定性而导致的剩余误差之和相同。
Abstract. Anelasticity may decrease the shear modulus of the asthenosphere by 8 %–10 % at semidiurnal tidal periods compared with the reference 1 s period of seismological Earth models. We show that such anelastic effects are likely to be significant for ocean tide loading displacement at the M2 tidal period around the East China Sea. By comparison with tide gauge observations, we establish that from nine selected ocean tide models (DTU10, EOT11a, FES2014b, GOT4.10c, HAMTIDE11a, NAO99b, NAO99Jb, OSU12, and TPXO9-Atlas), the regional model NAO99Jb is the most accurate in this region and that related errors in the predicted M2 vertical ocean tide loading displacements will be 0.2–0.5 mm. In contrast, GPS observations on the Ryukyu Islands (Japan), with an uncertainty of 0.2–0.3 mm, show 90th-percentile discrepancies of 1.3 mm with respect to ocean tide loading displacements predicted using the purely elastic radial Preliminary Reference Earth Model (PREM). We show that the use of an anelastic PREM-based Earth model reduces these 90th-percentile discrepancies to 0.9 mm. Use of an anelastic radial Earth model consisting of a regional average of the laterally varying S362ANI model reduces the 90th-percentile to 0.7 mm, which is of the same order as the sum of the remaining errors due to uncertainties in the ocean tide model and the GPS observations.