Vertical Land Motion by satellite Altimetry and tide gauge Difference

卫星测高和潮汐计差异的垂直陆地运动

• 批准号: 411072120
• 负责人: Dr. Marcello Passaro
• 金额: --
• 依托单位: Deutsches Geodätisches Forschungsinstitut
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/411072120?language=en
• 关键词: Vertical; Land; Motion; satellite; Altimetry

The impact that sea level rise will have at particular locations depends also on the local movements of the Earth crust, as vertical land motion (VLM) is in many places of the same order of magnitude (1-10 mm/yr) as the sea level rise itself and displays significant spatial variations. Given the potentially hazardous effects of sea level rise, measuring and interpreting the sea level trends relative to the land are vital challenges for climate change understanding and adaptation.To separate the contributions from crustal motions and absolute sea level rise from the in-situ (tide gauges, TGs) observations, geodetic VLM estimates can be used if a coastal geodetic stations and a TG are co-located, which is true for only 5% of the network. To extend the estimations to the other TGs, satellite altimetry, which provides absolute sea level measurements and has a global coverage, can be used in combination by differentiating the sea level time series, assuming that the residuals are due to the land motion (TG-Alt method). The accuracy of this promising application has been hampered by the quality of satellite altimetry data in the coastal zone.This project aims at providing a VLM map based on TG-Alt using for the first time a coastal-dedicated reprocessing of the altimetry data, including a specialised algorithm to fit the radar signal and an evaluation of the available corrections. A "zone of influence" of the sea level variability for each tide gauge will be defined in order to take into account the short wavelength variations typical of shelf seas and coastal waters, while maximizing the number of altimetry measurements. The uncertainties will be provided by the statistical analysis of TG-Alt residuals.A further aim is to improve the density of the geodetic network by harmonising the solutions of multiple datasets in order to make compatible the vertical motion rates referred to different Terrestrial Reference Frame (TRF) versions. These estimates will then be used as control points to evaluate the TG-Alt VLM map. Finally, the overall purpose is the estimation of relative coastal sea level trends during the "satellite era" (starting from 1993) by combining the altimetry data with the TG-Alt VLM points in a coastal map to be defined in specific regions. The resulting map of relative trends will constitute an innovative tool to be used, for example for risk assessment studies.

海平面上升对特定地点的影响还取决于地壳的局部运动，因为垂直陆地运动（VLM）在许多地方与海平面上升本身具有相同的数量级（1-10毫米/年），并表现出显著的空间变化。鉴于海平面上升的潜在危险影响，测量和解释相对于陆地的海平面趋势是了解和适应气候变化的重要挑战。为了将地壳运动和绝对海平面上升的贡献从原位（潮汐计，TG）观测中分离出来，如果沿海大地测量站和TG共存，则可以使用大地VLM估计，这种情况仅适用于5%的网络。为了将估算扩展到其他TGs，可以通过区分海平面时间序列来结合使用卫星测高，它提供了绝对的海平面测量并具有全球覆盖范围，假设残差是由陆地运动引起的（TG-Alt方法）。沿海地区卫星测高数据的质量阻碍了这一前景广阔的应用的准确性。该项目旨在提供基于TG-Alt的VLM地图，首次使用海岸专用的高程数据再处理，包括适合雷达信号的专门算法和可用修正的评估。将为每个潮汐计确定一个海平面变率的“影响区”，以便考虑到大陆架海和沿海水域典型的短波长变化，同时尽量增加测高测量的次数。不确定性将由TG-Alt残差的统计分析提供。进一步的目标是通过协调多个数据集的解决方案来提高大地测量网的密度，以使不同地面参考系（TRF）版本参考的垂直运动速率兼容。这些估计值将被用作控制点来评估TG-Alt VLM地图。最后，总体目的是在“卫星时代”（从1993年开始）通过将测高数据与在特定区域定义的沿海地图上的TG-Alt VLM点相结合来估计相对沿海海平面趋势。由此产生的相对趋势图将成为一种创新的工具，例如用于风险评估研究。