Mantle plumes and the geoid: Plume dynamics and their signature in the GRACE derived gravity field

我们将系统地研究地幔柱与大地水准面或重力和动态地形之间的关系，以识别地幔柱并解决其上/下地幔结构，动力学，（横向变化）流变学及其起源。在多达两个案例研究中，将区分羽流的表面效应和深部效应，并将使用区域地震层析成像异常来拟合剩余重力场和动态地形。在一个更一般的方法合成羽流，观测到的重力场和地形将进行分析和特点的空间和尺度相关的小波分析。这将允许羽流的区域空间和频率特性，它们对重力场的影响以及它们对地形的具体影响。因此，它给出了在尺度和空间上的导纳（大地水准面与地形的谱比）的表示，即导纳的频率特性的空间演化。通过与模拟的场特征进行比较，将尝试从重力场探测羽流并将其分类为不同的羽流组。需要CHAMP、GRACE对重力位和大地水准面进行高精度观测，以区分不同类型的羽流。作为副产品，超快幂律流变羽流的重力场和动态地形的时间依赖性将进行研究，并与GRACE数据进行比较。

We will systematically study the relation between plumes and the geoid or gravity and dynamic topography to identify plumes and resolve their upper/lower mantle structure, their dynamics, their (laterally varying) rheology, and their origin. In up to two case studies surface effects of plumes will be discriminated from deep effects and regional seismic tomography anomalies will be used to fit the residual gravity field and the dynamic topography. In a more general approach synthetic plumes, the observed gravity field and the topography will be analysed and characterized by a spatially and scale dependent wavelet analysis. This will allow a regional space and frequency characterization of plumes, their effects to the gravitational field as well as their specific influences on topography. In consequence, it gives a representation of the admittance (spectral ratio of geoid to topography) in scale and space, i.e. the spatial evolution of the frequency properties of the admittance. By comparison with modelled field characteristics detection of plumes from the gravity field and a classification into different plume groups will be tried. High precision observations of the gravity potential and the geoid by CHAMP, GRACE will be needed to differentiate between different types of plumes. As a byproduct, the time dependence of the gravity field and dynamic topography of ultrafast power-law rheology plumes will be studied and compared to GRACE data.