The quality of the Data Unification and Altimeter Combination System (DUACS) Sentinel-3A altimeter data in the coastal area of the European seas is investigated through a comparison with in situ tide gauge measurements. The comparison was also conducted using altimetry data from Jason-3 for inter-comparison purposes. We found that Sentinel-3A improved the root mean square differences (RMSD) by 13% with respect to the Jason-3 mission. In addition, the variance in the differences between the two datasets was reduced by 25%. To explain the improved capture of Sea Level Anomaly by Sentinel-3A in the coastal band, the impact of the measurement noise on the synthetic aperture radar altimeter, the distance to the coast, and Long Wave Error correction applied on altimetry data were checked. The results confirmed that the synthetic aperture radar altimeter instrument onboard the Sentinel-3A mission better solves the signal in the coastal band. Moreover, the Long Wave Error processing contributes to reduce the errors in altimetry, enhancing the consistency between the altimeter and in situ datasets.

中文翻译：

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评估欧洲海洋沿海带的DUACS Sentinel-3A测高数据：与潮汐仪的比较

通过与原位潮汐仪测量值进行比较，研究了欧洲海沿岸数据统一和高度计组合系统（DUACS）Sentinel-3A高度计数据的质量。为了进行比较，还使用了Jason-3的测高数据进行了比较。我们发现，与Jason-3任务相比，Sentinel-3A的均方根差（RMSD）提高了13％。此外，两个数据集之间差异的方差减少了25％。为了解释Sentinel-3A在沿海带对海平面异常的捕获的改善，我们检查了测量噪声对合成孔径雷达高度计，到海岸的距离以及应用于测高仪数据的长波误差校正的影响。结果证实，Sentinel-3A任务上的合成孔径雷达高度计仪器可以更好地解决沿海地区的信号。此外，长波误差处理有助于减少测高中的误差，增强高度计与原位数据集之间的一致性。