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

拟议的研究旨在根据两种大地测量和监测技术的最佳估计组合，创建英国当前垂直土地运动的地图；绝对重力（AG）的测量和高精度连续GPS （CGPS）观测的使用。从长期的地质和地球物理研究来看，英国的垂直陆地运动被认为是每年1到2毫米，苏格兰上升，英格兰南部下沉，因此英国实际上是“倾斜”的。自1997年以来，IESSG和NERC-POL一直在合作研究利用AG和CGPS监测这一级别的垂直陆地运动。过去的研究主要集中在潮汐测量仪上使用AG和CGPS，目的是测量英国海岸周围海平面的当前变化（与陆地水平的变化脱钩）。对于拟议的研究，我们将把我们的分析从传统的关注大不列颠海岸的潮汐计扩展到考虑英国所有可用的CGPS站。有140个这样的CGPS站点，它们提供了一个站点间隔约50公里的网络密度，位于英国各地的各种地质环境中。我们还将改进我们的分析，利用大地测量和监测的最新信息、思想和软件，对陆地垂直运动进行新的和改进的估计。拟议的研究是一个小型的离散项目，将是第一次尝试创建英国当前垂直陆地运动的地图，该地图基于AG和众多CGPS站的最佳组合。有了这样一张地图，就有可能使用模型预测未来海平面的变化，以便更好地评估未来海平面的变化与英国所有沿海地区的陆地有关。拟议的研究也可视为概念证明研究，因为140个监测站中的一些由于时间序列相对较短而不适合，但随着将来安装更多监测站和/或延长时间序列，将来显然可以改进地图。

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.