Meso and submesoscale structures from the Geostationary Ocean Color Imager and a model in the southwestern East Sea

Abstract

Using high resolution (~500 m) ocean color images taken by the Geostationary Ocean Color Imager we investigated the power spectral density (PSD) of meso and submesoscale flow features in summer and winter separately over the southwestern part of the East Sea. Over the mesoscale range the power dependence of PSD to wavelength k was about -1.7 in both seasons. Over the submesoscale range the power dependence was smaller but showed seasonal difference. The power dependence was smaller in winter suggesting stronger submesoscale activities. We confirmed these findings using a high resolution ocean circulation model. The strength of mixing estimated using the Finite-Size Lyapunov Exponents and vertical relative dispersion coefficients with the model outputs was highly correlated with the submesoscale features rather than the mesoscale ones although the energy level of the former is much smaller than that of latter. Thus mixing would be stronger during winter when submesosacle flows are more active.rt of the East Sea. Over the mesoscale range the power dependence of PSD to wavelength k was about -1.7 in both seasons. Over the submesoscale range the power dependence was smaller but showed seasonal difference. The power dependence was smaller in winter suggesting stronger submesoscale activities. We confirmed these findings using a high resolution ocean circulation model. The strength of mixing estimated using the Finite-Size Lyapunov Exponents and vertical relative dispersion coefficients with the model outputs was highly correlated with the submesoscale features rather than the mesoscale ones although the energy level of the former is much smaller than that of latter. Thus mixing would be stronger during winter when submesosacle flows are more active.