Development and application of a three-dimensional viscoelastic lithosphere and mantle model for reducing GRACE-gravity data (VILMA)

地球对末次冰川(距今10000年)以及对十年(&lt；100年)和最近冰川变化(&lt；10年)的延迟响应在化石海平面指标、重力重力、GPS、验潮仪和测高观测中都很明显，必须用粘弹性地幔流变学来模拟。预测冰川引起的响应可以将其与其他贡献分开，例如水文和海洋引起的变化。S岩石圈和地幔粘弹性结构的横向变化与数千公里的空间尺度上的板块构造单元有关，必须在本计划涵盖的全球尺度上加以考虑。在这个项目中，将开发一个三维(3-D)地球模型。与一维地球模型相比，它的优点是可以同时受到与不同构造单元有关的所有载荷的强迫，以计算地球的全球尺度响应。这将导致对结构单元和不同加载模式之间的机械耦合的一致描述。除了粘度的横向变化外，非静力初始应力场将使冰川均衡调整与现今的地幔对流联系起来。使用3D地球模型的另一个原因是，它适用于阿拉斯加、南极洲、冰岛、巴塔哥尼亚和斯瓦尔巴群岛等构造边界附近的地区。沿着所有这些边界，可以观察到最近的冰川变化，而用一维地球模型来模拟它们是不够的。

The delayed response of the Earth to the last glaciation (> 10; 000 years before present) as well as to decadal (< 100 years) and recent glacial changes (< 10 years) is evident in fossil sea-level indicators, GRACE-gravity, GPS, tide-gauge and altimetry observations, and must be modeled by a viscoelastic mantle rheology. Predicting the glacially-induced response allows the separation from other contributions such as hydrologically and oceanographically induced changes. Lateral variations in the viscoelastic structure of the Earth¿s lithosphere and mantle that are related to plate-tectonic units on spatial scales of thousands of kilometres must be considered on the global scale covered by this program. In this project, a three-dimensional (3-D) earth model will be developed. In comparison to one-dimensional (1-D) earth models, it has the advantage that it can be forced by all loads related to different tectonical units simultaneously in order to compute the global-scale response of the Earth. This will result in a consistent description of the mechanical coupling between the structural units and the different loading patterns. In addition to lateral variations in viscosity, a non-hydrostatic initial stress field will allow the linkage of glacial-isostatic adjustment to present-time mantle convection. Another reason for using a 3-D earth model is that it is applicable to regions near tectonic boundaries, such as Alaska, Antarctica, Iceland, Patagonia and Svalbard. Along all these boundaries, recent glacial changes are observed, and their modeling with a 1-D earth model is inadequate.