Seasonal and diurnal variations of vorticity and divergence in the
Eastern Boundary Current Systems
Abstract
Eastern Boundary Currents Systems are typically studied as a whole due
to their dynamical similarities, mainly because Ekman pumping is
predominant at these currents, and they typically have low kinetic
energy. In this study, we used the output of a high-resolution global
simulation to make a dynamical comparison among the California, Canary,
Peru, and Benguela currents during the winter and summer months,
focusing on submesoscale motions (Ro ~ 1) in both the
frequency-wavenumber and space-time domains. After we confirmed the
presence of submesoscale activity and isolated it from mesoscale
motions, we found that their divergence and vorticity fields follow
similar seasonal patterns in the near-diurnal frequency range, despite
regional differences. The results showed that heat fluxes at the ocean
surface, along with weak to moderate wind stresses, significantly impact
the modulation of submesoscale vorticity and divergence fields at
diurnal frequencies.