The Creation of a Map of Current Vertical Land Movements in the UK based on an Optimal Combination of Absolute Gravity and Continuous GPS

这项拟议的研究旨在基于两种大地测量和监测技术的估计的最佳组合创建英国当前垂直陆地运动的地图：测量绝对重力(AG)和使用高精度、连续的GPS(CGPS)观测。根据长期的地质和地球物理研究，英国的垂直陆地运动被认为是每年1到2毫米的量级，苏格兰上升，英格兰南部下沉，因此大不列颠实际上正在“倾斜”。自1997年以来，IESSG和NERC-POL一直在合作进行与使用AG和CGPS监测这类垂直陆地运动有关的研究。过去的研究主要集中于AG和CGPS在验潮仪上的使用，目的是测量大不列颠海岸周围海平面的海流变化(与陆地水位的变化脱钩)。对于拟议的研究，我们将把我们的分析从传统的专注于英国海岸周围的潮汐测量仪扩展到考虑英国所有可用的CGPS站。英国有140个这样的CGPS站，它们提供了一个密度较大的网络，站间距约为50公里，分布在英国各地的各种地质环境中。我们还将改进我们的分析，利用可用于大地测量和监测的最新信息、想法和软件，对垂直陆地运动作出新的和改进的估计。这项拟议的研究是一个小型的离散项目，将首次尝试基于AG和如此多的CGPS站点的最佳组合来创建英国当前的垂直陆地运动地图。有了这样的地图，就有可能使用海平面未来变化的模型预测，以便更好地评估联合王国所有沿海地区未来相对于陆地的海平面变化。拟议的研究也可被视为概念验证研究，因为140个站点中的一些站点由于时间序列较短而不适合，但随着未来安装更多站点和(或)时间序列延长，地图的未来改进显然是可能的。

The proposed research aims to create a map of current vertical land movements in the UK based on an optimal combination of estimates from two geodetic surveying and monitoring techniques; the measurement of absolute gravity (AG) and the use of high precision, continuous GPS (CGPS) observations. From long term geological and geophysical studies, vertical land movements in the UK are thought to be of the order of 1 to 2 millimetres per year, with Scotland rising and the South of England subsiding, so that Great Britain is effectively 'tilting'. IESSG and NERC-POL have been working collaboratively on research related to the use of AG and CGPS for monitoring vertical land movements of this order since 1997. This past research has primarily focused on the use of AG and CGPS at tide gauges, with the aim of measuring current changes in sea level (decoupled from changes in land level) around the coast of Great Britain. For the proposed research, we will be extending our analysis from our traditional focus on tide gauges around the coast of Great Britain to consider all available CGPS stations in the UK. There are 140 such CGPS stations, which provide a density of network with station separations of about 50km, located in various geological settings throughout the UK. We will also be refining our analysis to produce new and improved estimates of vertical land movements, using the latest information, ideas and softwares available for geodetic surveying and monitoring. The proposed research is a small discrete project and will be the first attempt to create a map of current vertical land movements in the UK based on an optimal combination of AG and so many CGPS stations. With such a map it will be possible to then use model predictions of future changes in sea level in order to better assess future changes in sea level with respect to the land for all coastal regions of the UK. The proposed research could also be considered as a proof-of-concept study, as some of the 140 stations will not be suitable, due to their relatively short time series, but future refinement of the map will clearly be possible as more stations are installed and/or time series are extended in the future.