An anelastic evolutionary geodynamo simulation driven by compositional and thermal convection
An anelastic evolutionary geodynamo simulation driven by compositional and thermal convection
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DOI：
10.1016/0167-2789(96)00100-5
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发表时间：
1996-10-01
影响因子：
4
通讯作者：
Roberts, PH
中科院分区：
文献类型：
--
作者：
Glatzmaier, GA;Roberts, PH
我们已经延长了我们的地球发电机模拟40000年，使用更现实的热力学和对流表示。滞弹性近似取代了Boussinesq近似;除了热浮力之外，成分浮力还驱动着流体外核的对流。内核边界处的边界条件模拟了重组分在固体内核上的冻结和轻组分在流体外核中的释放。由此产生的模拟磁场有一个强烈的偶极主导的结构以外的核心，类似于地球的领域，到目前为止，没有显示出扭转其偶极极性的趋势。核幔边界的非偶极结构也与地球的结构非常相似，包括其总体向西漂移的速率。在我们最初的模拟中，固体内核通常比地幔快1度/年左右，这与最近对地球的地震研究一致。这种三维自洽解似乎是在模拟地球发电机在反转之间的稳定状态。
We have extended our geodynamo simulation 40000 years using a more realistic representation of the thermodynamics and convection. The anelastic approximation replaces the Boussinesq approximation; and compositional buoyancy, in addition to thermal buoyancy, drives convection in the fluid outer core. Boundary conditions at the inner core boundary model the freezing of the heavy constituent onto the solid inner core and the release of the light constituent into the fluid outer core. The resulting simulated magnetic field has a strongly dipole dominated structure outside the core, similar to the Earth's field, so far displaying no tendency to reverse its dipole polarity. The non-dipolar structure of the field at the core-mantle boundary is also quite similar to the Earth's, including the rate of its general westward drift. As in our original simulation, the solid inner core typically rotates about 1 degrees/yr faster than the mantle, in agreement with recent seismic studies of the Earth. This three-dimensional self-consistent solution seems to be simulating the stable regime of the geodynamo between reversals.