Polar motion excitations for an Earth model with frequency-dependent responses: 1. A refined theory with insight into the Earth's rheology and core-mantle coupling
Polar motion excitations for an Earth model with frequency-dependent responses: 1. A refined theory with insight into the Earth's rheology and core-mantle coupling
复制标题
具有频率相关响应的地球模型的极地运动激励：1.深入了解地球流变学和核幔耦合的精炼理论
DOI：
10.1002/jgrb.50314
复制
发表时间：
2013-09-01
影响因子：
3.9
通讯作者：
Shen, WenBin
中科院分区：
文献类型：
--
作者：
Chen, Wei;Ray, Jim;Shen, WenBin
本研究的目的是改进极移理论，通过开发精细的频率依赖的传递函数与最新的海洋潮汐模型，地球流变学和核幔耦合。首先，我们提出了一个幂律地幔滞弹性约束的钱德勒周期T-CW和品质因子Q（CW）和一个经验准流体流变学模型与频率的线性依赖，这是适合于一个长达18.6年的周期。然后采用国际地球自转和参考系服务公约（2010）中的昼夜海洋潮汐、Dickman和Gross（2010）的长周期海洋模型以及Desai（2002）的平衡海洋极潮模型计算Love数的海洋改正。此外，我们提出的讨论的地球物理和观测方面的钱德勒周期TCW和品质因子Q（CW），并提供了优选的值和间隔的T-CW和Q（CW），这使我们能够放置一些约束的地幔滞弹性和核幔耦合比（CW）。虽然（CW）受T-CW和Q（CW）不确定性的影响，但我们发现它的真实的部分应该在2%-3%，而虚部可能只有千分之几。最后，基于上述频变洛夫数模型和核幔耦合模型，确定了频变极移传递函数TL和T-NL。我们的传递函数与T-CW和Q（CW）的值有关，然而，我们的分析表明，我们的传递函数是相当稳定的，对T-CW和Q（CW）的扰动不敏感。
This study aims to improve the polar motion theory by developing refined frequency-dependent transfer functions with the most current models for ocean tides, the Earth's rheology, and core-mantle coupling. First, we present a power law for mantle anelasticity constrained by the Chandler period T-CW and quality factor Q(CW) and an empirical quasi-fluid rheology model with a linear dependence on frequency, which is suitable for a period as long as similar to 18.6 years. Then we adopt the diurnal ocean tides from the International Earth Rotation and Reference Systems Service Conventions (2010), the long-period ocean model of Dickman and Gross (2010), and the equilibrium ocean pole tide model of Desai (2002) to calculate the oceanic corrections to the Love numbers. Further, we present discussions on the geophysical and observational aspects of the Chandler period TCW and quality factor Q(CW), and provide preferred values and intervals for T-CW and Q(CW), which allow us to place some constraints on the mantle anelasticity and core-mantle coupling ratio (CW). Although (CW) is affected by uncertainties in T-CW and Q(CW), we find its real part should be around 2%-3% while its imaginary part might be only a few thousandths. Finally, the frequency-dependent polar motion transfer functions T-L and T-NL are determined based on the models of frequency-dependent Love numbers and core-mantle coupling discussed above. Our transfer functions are related to the values of T-CW and Q(CW), however, our analyses demonstrate that our transfer functions are rather stable and not sensitive to perturbations in T-CW and Q(CW).