A New Approach to Estimate Ocean Surface Velocity from High-Resolution Surface Water and Ocean Topography (SWOT) Data
This study presents a novel cyclostrophic balance correction method for estimating submesoscale ocean surface currents in the Northern Arabian Sea using surface water and ocean topography (SWOT) mission altimetry. High-resolution Ocean Color Monitor (OCM-3) data from the EOS-06 satellite reveal fine-scale eddies and filaments with high chlorophyll-a concentrations (>0.4 mg m−3), spatially coherent with geostrophic current patterns from SWOT. At these scales, the geostrophic assumption is invalid; therefore, we introduce a curvature-based cyclostrophic correction that accounts for enhanced centripetal accelerations. Validation against high-resolution model simulations shows that our approach is in better agreement with model outputs than uncorrected and previously published corrected fields, particularly in regions with strong vorticity and strain. When applied to SWOT data, the corrected velocities demonstrate spatial correspondence with chlorophyll patterns and suppress spurious gradients. Probability density functions of normalized vorticity and strain also match theoretical expectations, emphasizing the potential of SWOT for advancing submesoscale ocean dynamics.