On retrodictions of global mantle flow with assimilated surface velocities
On retrodictions of global mantle flow with assimilated surface velocities
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DOI：
10.1002/2015gl066001
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发表时间：
2015-10-28
影响因子：
5.2
通讯作者：
Schuberth, Bernhard S. A.
中科院分区：
文献类型：
--
作者：
Colli, Lorenzo;Bunge, Hans-Peter;Schuberth, Bernhard S. A.
对地球地幔过去的状态进行建模并将其与大陆尺度的隆升和沉降等地质观测联系起来是测试地幔对流模型的有效方法。然而，地幔对流是混乱的，两个相同的地幔模型以稍微不同的温度场初始化，随着时间的推移呈指数级分化，直到它们变得不相关，从而将回溯（即使用当前信息重建地幔的过去状态）限制在最近的过去。我们通过 3-D 球形地幔对流模型表明，如果可以获得表面速度场的知识，则可以显着扩展地幔流的回归。在某些情况下，同化表面速度会产生负李雅普诺夫时间（即 e 折叠时间），这意味着即使初始条件受到严重扰动，也可能向参考状态演化。地球表面速度场的历史可以从过去地幔翻转时期的板块运动重建中获得，这表明可以在可比较的时间内重建地幔流。
Modeling past states of Earth's mantle and relating them to geologic observations such as continental-scale uplift and subsidence is an effective method for testing mantle convection models. However, mantle convection is chaotic and two identical mantle models initialized with slightly different temperature fields diverge exponentially in time until they become uncorrelated, thus limiting retrodictions (i.e., reconstructions of past states of Earth's mantle obtained using present information) to the recent past. We show with 3-D spherical mantle convection models that retrodictions of mantle flow can be extended significantly if knowledge of the surface velocity field is available. Assimilating surface velocities produces in some cases negative Lyapunov times (i.e., e-folding times), implying that even a severely perturbed initial condition may evolve toward the reference state. A history of the surface velocity field for Earth can be obtained from past plate motion reconstructions for time periods of a mantle overturn, suggesting that mantle flow can be reconstructed over comparable times.