Vertical Crustal Movements in the Upper Rhine Graben Derived from Precise Levelling Data, SAR Interferometry and GNSS

我们项目的目标是开发一种方法，使用水准测量、持续散射SAR干涉测量(PSI)和全球导航卫星系统(GNSS)相结合的方法来获取上莱茵河地块(URG)地区的大尺度三维速度场。在该项目的第一部分，由德国研究基金会(DFG)资助，通过对德国、法国和瑞士的跨国水准测量数据进行一致的最小二乘平差，确定了垂直位移分量的基础。在现适用的研究项目第二部分中，应将从PSI和URG中连续运行的全球导航卫星系统站点的时间序列得出的位移速率添加到水准数据中，以便在空间上增密关于垂直位移的现有信息，并量化水平位移。为此，应采用PSI方法，在巴塞尔和曼海姆之间250公里长、100公里宽的范围内分析C波段卫星ERS1/2和ENVISAT的合成孔径雷达场景。关于利用C波段数据档案探测长波位移现象，重点是实施和测试在PSI处理链中分离轨道误差的新程序。关于全球导航卫星系统的分析，该项目可受益于在卡尔斯鲁厄理工学院大地测量研究所开展的全面前期工作，并直接利用全球导航卫星系统上莱茵河地块网络(GURN)各站点的水平和垂直位移速率的结果。该项目第二部分的主要重点是将探测地表位移的三种大地测量技术(水准、PSI、GNSS)结合起来，以便在高空间分辨率下得出整个URG的一致的三维速度场。该方法应以最佳方式利用测量技术(精确度、空间和时间分辨率)的个别优势。由于这三种技术的数据和结果在空间和时间上是不均匀的，(Ii)与不同的参考水平有关，因此必须开发和应用合适的内插方法来解决目前的组合问题。由于测点分布可能存在很大的不均匀性，除了使用克立格法进行空间内插外，还应研究数据的直线内插方法。除了地表位移的探测和建模外，该研究项目的另一个重点是分离人为、环境(非构造)和构造变形。在进行大规模研究时，必须尽可能省略因人为开采地下而出现局部位移异常的地区，但这可能有助于进行详细调查和敏感性分析。

The goal of our project is the development of a methodology to derive large-scale, three-dimensional velocity fields in the Upper Rhine Graben (URG) area using a combination of levelling, Persistent Scatterer SAR interferometry (PSI) and GNSS. In the first part of this project, granted by German Research Foundation (DFG), the basis for the vertical displacement component has been set by consistent least squares adjustment of transnational levelling data from Germany, France and Switzerland. In the hereby applied second part of the research project, displacement rates derived from PSI and from time series of continuously operating GNSS sites in the URG shall be added to the levelling data in order to spatially densify the existing information on the vertical displacements as well as to quantify horizontal displacements. To this end, SAR scenes of the C-band satellites ERS1/2 and ENVISAT shall be analysed in a 250 km long and 100 km wide stripe between Basel and Mannheim by applying the PSI method. With respect to the detection of long-wave displacement phenomena using the C-band data archive, the focus is on the implementation and testing of a new procedure for the separation of orbit errors in the PSI processing chain. Concerning the GNSS analysis the project can benefit from comprehensive preliminary work, carried out at Geodetic Institute, Karlsruhe Institute of Technology, and directly use the results for horizontal and vertical displacement rates at the sites of the GNSS Upper Rhine Graben network (GURN). The main focus of the second part of the project is on a combination of the three geodetic measurement techniques for the detection of surface displacements (levelling, PSI, GNSS) in order to derive a consistent, three-dimensional velocity field for the whole URG at a high spatial resolution. The approach shall exploit the individual advantages of the measurement techniques (accuracy, spatial and temporal resolution) in an optimum way. As the data and the results of the three techniques are (i) inhomogeneous in space and time, and (ii) related to different reference levels, appropriate interpolation methods have to be developed and applied on the present combination problem. Because of the presumably large inhomogeneity in the distribution of the measurement points, approaches for a line-wise interpolation of the data shall be investigated in addition to the spatial interpolation using the Kriging method. Besides the detection and modelling of the surface displacements another focus of the research project is on the separation of anthropogenic, environmental (non-tectonic) and tectonic deformation. Areas with local displacement anomalies due to anthropogenic exploitation of the subsurface have to be omitted as far as possible for large-scale studies, but may be useful for detailed investigations and sensitivity analyses.