660 / 2024-09-18 20:33:20

Application of SWOT data in oceanic fine-scale dynamics in the northwestern Pacific and South China Sea

Fine-scale dynamics,SWOT mission,South China Sea,Northwestern Pacific

Session 46 - Oceanic Mesoscale and Submesoscale Processes: Characteristics, Dynamics & Parameterizations

High-resolution sea surface height measurements from the Surface Water and Ocean Topography (SWOT) mission provide a great opportunity to detect fine-scale processes in global ocean. However, whether SWOT can resolve these processes effectively is unclear. As a part of the Adopt-A-Crossover consortium to support the SWOT calibration and validation (CalVal), the Ocean University of China initiated the North West Pacific campaign, which deployed four moorings under the SWOT CalVal orbit in the northwestern Pacific Subtropical Countercurrent region. Based on the moored observations, 1-day SWOT data and nadir-looking altimetry data during the CalVal periods, we revealed that SWOT observed many submesoscale eddies riding on the mesoscale eddies, compared to the nadir-looking altimeters. These eddies have spatial and temporal scales shorter than 50 km and 16 days, respectively. Two submesoscale cyclonic eddies were also observed by the mooring array. Their effective radii are 16.0 km and 18.8 km, respectively. The moored observations indicate that their Rossby number  and their  horizontal velocity can exceed 0.4 and 15.0 cm/s, respectively. Also, in the South China Sea, based on the science-phase SWOT data, we found that the SWOT observed abundant fine-scale processes. The features and map of these fine-scale signals in the South China Sea were given. These results indicate that SWOT can well detect oceanic fine-scale processes, which will help us further understand  oceanic dynamics.