Structure of the magnetic lithosphere from joint analysis of satellite and airborne data

该提案是在全球范围内继续开展磁性岩石圈工作，这项工作是在"从全球卫星数据分析磁性岩石圈结构"项目的特别方案第一阶段开始的。第一个项目旨在通过对重力和磁力卫星数据的联合分析，结合地震结果，估计全球范围内磁性岩石圈的特性（磁化、厚度、成分）。磁岩石圈的电流表示，地壳和上地幔的一部分，可以包含磁化，这里被用作先验信息的航磁数据反演。其目的是建立混合模型，可以解释不同的光谱域所代表的卫星和航磁观测。一个重要的因素是扩展现有的逆向建模代码，以便能够以一致的方式处理多个数据集，并在贝叶斯框架中研究影响反演结果的不同元素之间的交叉依赖关系。逆代码将针对基于来自第一SPP阶段的真实的3D地球描述和更多本地信息的现实实现的合成示例进行测试。接下来，反演将应用于区域航磁汇编（如环北极、南极洲、澳大利亚、加拿大），以获得高分辨率磁化模型。将仔细研究来自岩石物理数据和其他地球物理方法的约束的影响，以提供对所获得的结果的不确定性。例如，这对于定义任何地质解释的置信水平是重要的，该置信水平进一步用于解决热流或其他问题的研究。一个相关的方面是一项研究内容，涉及新的卫星配置对现有Swarm卫星轨道变化的增益和延长的Swarm使命周期，以及较低轨道高度的额外卫星可能带来的好处。

The proposal is presenting a continuation of the work on the magnetic lithosphere on a global scale, which started in the first phase of the SPP in the project “Structure of the magnetic lithosphere from global analysis of satellite data”. The first project aimed at estimating the properties of the magnetic lithosphere on a global scale (magnetization, thickness, composition) from joint analysis of gravity and magnetic satellite data in combination with seismic results. The current representation of the magnetic lithosphere, the part of crust and upper mantle that can contain magnetization, is used here as a-priori information in the inversion of aeromagnetic data. The aim is to build hybrid models that can explain the different spectral domains represented by satellite and aeromagnetic observations. An important element is to extend existing inverse modelling codes to be able to handle multiple data sets in a consistent manner and to study in a Bayesian framework the cross-dependencies between the different elements influencing the inversion results. The inverse code will be tested against synthetic examples based on the real 3D Earth description from the first SPP phase and realistic implementation of more local information. Next, the inversion will be applied to regional aeromagnetic compilations (e.g. Circum-Arctic, Antarctica, Australia, Canada) to achieve high-resolution magnetization models. The influence of constraints from petrophysical data and other geophysical methods will be studied carefully to provide uncertainties on the obtained results. This is for example important to define a confidence level of any geologic interpretation that is further on used for studies addressing heat-flow or other. A related aspect is a study element addressing the gain by new satellite configuration with respect to change in orbit for the existing Swarm satellites and the extended Swarm mission period and the possible benefit from additional satellites at lower orbit height.