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利用超导重力技术约束核幔耦合参数

, PP. 202-210

Keywords: 超导重力仪器观测,地球液核自由章动,核幔边界粘滞系数,电导率,地核动力学椭率

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Abstract:

?地球液核自由章动(FCN)参数(本征周期和品质因子)与核幔边界的粘滞和电磁等耗散耦合密切相关,基于实际观测与理论推导的FCN参数探讨了液核顶部的粘滞系数,地幔底部的电导率以及核幔边界动力学椭率等核幔耦合机制中的关键参数.根据高精度超导重力仪观测序列调和分析标准差和单个台站资料经不同海潮模型改正后拟合的FCN参数质量,对全球地球动力学合作观测网络台站的超导重力观测资料进行筛选,利用多个最新海潮模型计算平均海潮负荷,并用迭积法拟合了FCN参数,结果与最新超导重力和VLBI同类研究结果一致.在此基础上,结合角动量法推导地FCN理论模型研究了核幔边界的粘滞和电磁耦合参数.数值结果表明液核顶部的粘滞系数应该在6.6×102~2.6×103Pas之间,这与根据地球章动,液核自由章动及日长变化等的实际观测得到的粘滞系数结果非常吻合.地幔底部的电导率需要达到2.6×106~1.0×107Sm-1才能符合实际观测的FCN品质因子量级.耗散耦合对FCN本征周期的影响仅为1~2恒星日.

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