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

用于简化GRACE重力数据的三维粘弹性岩石圈和地幔模型的开发和应用（VILMA）

• 批准号: 30183888
• 负责人: Professor Dr. Maik Thomas, since 5/2012
• 金额: --
• 依托单位: Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum (GFZ)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/30183888?language=en
• 关键词: Development; application; three; dimensional; viscoelastic

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.

地球对末次冰期（距今> 10，000年）以及年代际（< 100年）和近期冰期（< 10年）的延迟响应在化石海平面指示器、GRACE重力仪、GPS、验潮仪和测高观测中是明显的，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从其他贡献，如水文和海洋引起的变化分离。地球岩石圈和地幔粘弹性结构的横向变化与数千公里空间尺度上的板块构造单元有关，必须在本方案所涵盖的全球范围内加以考虑。在这个项目中，将建立一个三维地球模型。与一维地球模型相比，它的优点是可以同时承受与不同构造单元相关的所有载荷，以计算地球的全球尺度响应。这将导致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，一个非流体静力学的初始应力场将允许链接的冰川均衡调整到现今地幔对流。使用三维地球模型的另一个原因是它适用于构造边界附近的地区，如阿拉斯加，南极洲，冰岛，巴塔哥尼亚和斯瓦尔巴特群岛。沿着所有这些边界，最近的冰川变化被观察到，它们的建模与1-D地球模型是不够的。