EGUsphere EGUsphere EGUsphere EGUsphere Copernicus Publications Göttingen, Germany 10.5194/egusphere-2024-2773 Advances in Surface Water and Ocean Topography for Fine-Scale Eddy Identification from Altimeter Sea Surface Height Merging Maps Zhang Xiaoya 1 2 Liu Lei 1 2 Fei Jianfang 1 Li Zhijin https://orcid.org/0000-0003-1879-7866 3 Wei Zexun https://orcid.org/0000-0002-1217-6973 4 Zhang Zhiwei 5 Jiang Xingliang 3 Dong Zexin 1 Xu Feng 1 College of Meteorology and Oceanology, National University of Defense Technology, Changsha 410073, China Key Laboratory of High Impact weather (special), China Meteorological Administration, Changsha 410073, China Department of Atmosphere and Ocean Sciences, Institute of Atmospheric Sciences, Fudan University, Shanghai 200433, China First Institute of Oceanography, and Key Laboratory of Marine Science and Numerical Modeling, Ministry of Natural Resources, Qingdao 266061, China Frontier Science Center for Deep Ocean Multispheres and Earth System (FDOMES) and Physical Oceanography Laboratory/Key Laboratory of Ocean Observation and Information of Hainan Province, Sanya Oceanographic Institution, Ocean University of China, Qingdao/Sanya, China 08 10 2024 2024 1 19 Copyright: © 2024 Xiaoya Zhang et al. 2024 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://egusphere.copernicus.org/preprints/2024/egusphere-2024-2773/ The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2024/egusphere-2024-2773/egusphere-2024-2773.pdf

The recently launched Surface Water and Ocean Topography (SWOT) satellite mission has reduced the noise levels and increased resolution, thereby improving the ability to detect previously unobserved fine-scale signals. We employed a method to utilize the unique and advanced capabilities of SWOT to validate the accuracy of identified eddies in merged maps of a widely used Archiving, Validation, and Interpretation of Satellite Oceanographic (AVISO) data product and a newly implemented two-dimensional variational method (2DVAR), which uses a 1/12° grid and reduces decorrelation of spatial length scales. The findings indicate that SWOT provides an enhanced capability in resolving fine-scale and mesoscale eddies in the South China Sea compared with conventional in-situ data, such as drifting buoys. The validation results demonstrated that compared with AVISO, the 2DVAR method exhibited greater consistency with the SWOT observations, especially at small scales, confirming the accuracy and capability of the 2DVAR method in the reconstruction and resolution of fine-scale oceanic dynamical structures.