Regional coastal sea level change and sea level topography from altimetry, oceanography, and tide gauge stations in Europe

沿海地区是卫星测高面临的主要挑战之一，原因是高度计信号恶化和海岸附近环境改正对测高的影响。这些海岸效应阻碍了将测高数据与验潮仪数据结合起来用于卫星高度计校准、确定海平面变化(SLV)和相互验证海平面趋势。其目的有两个：a)监测海平面的长期变化；b)评估高度计技术在沿海/边缘地区的适用性。选择了两个具有互补特征的地区，即大西洋陆架上的比斯开湾和半封闭地中海盆地的地中海西北部。这项工作基于最新获得的高频(10赫兹或更高)测高数据和更适合沿海地区的改进的高度计改正。采用局部改正和专用波形处理相结合的方法，提高沿海地区高程测量的精度。此外，还将使用和分析标准的1赫兹数据。多卫星测高和验潮仪数据的结合将提高估计的海平面变化的空间和时间分辨率。讨论了多卫星高度计数据的区域统一问题，并对海平面高度测量的差异进行了研究。验潮站数据被用作地面真实数据，以调查海平面测量的变异性和绝对位置。除平均海平面和大地水准面模型外，还使用了当地正压和海洋模型的改正以及当地潮汐模型的剩余潮汐效应，以改善测高和验潮仪测量之间的一致性。在本项目的框架内，将通过优化组合新的测高数据集和验潮仪和海洋模型的非均匀数据，开发方法来构建改进的海平面变率和平均动态地形模型。

Coastal Areas are one of major challenges for Satellite Altimetry due to deterioration of altimeter signals and environmental corrections to altimetry near to the coast. The use of altimetry data in combination with tide gauge data for satellite altimeter calibration, sea level variability (SLV) determination and mutual validation of trends in sea levels is hindered by these coastal effects.Topic of the proposal is the improved estimation of sea level variability in coastal areas. The aim is twofold a) to monitor the long-term sea level variability and b) to assess the applicability of altimeter techniques in coastal/marginal regions. Two regions with complementary characteristics are selected, namely the Gulf of Biscay on the Atlantic Ocean shelf and the north-western Mediterranean Sea in the semi-enclosed Mediterranean Sea basin.The work is based on newly available altimetry data at high frequency (10 Hz of higher) and on improved altimeter corrections better suitable for coastal areas. With a combination of local corrections and dedicated waveform processing the accuracy of altimetric measurements in coastal region shall be improved. The standard 1-Hz data will be used and analyzed in addition. The combination of multi-satellite altimetry and tide gauge data shall improve the spatial and temporal resolution of the estimated sea level variability. The regional unification of multi-satellite altimeter data is addressed and discrepancies in the sea level height measurements are investigated. Tide gauge station data are used as ground truth to investigate both variability and absolute location of the sea level measurements. Correction from local barotropic and oceanographic models and of residual tidal effects from local tidal models are used in addition to mean sea level and geoid models to improve the agreement between altimetry and tide gauge measurements.In the framework of this project methodologies will be developed to construct improved models of sea level variability and of mean dynamic topography by optimally combing the new altimetry dataset and the heterogeneous data from tide gauges and oceanographic models.