| Abstrakt: |
The energetics of eddy‐mean flow interactions in the Brazil Current (BC) between 20°S and 36°S are investigated in 19 transects perpendicular to the 200 m isobath. Ten years (2000–2009) of output data from the Hybrid Coordinate Ocean Model (HYCOM) NCODA reanalysis, with a spatial resolution of 1/12.5° and 5 day averages, are used. The mean kinetic energy (MKE) and eddy kinetic energy (EKE) fields presented the same subsurface spatial pattern but with reduced values. The EKE increases southward, with high values along the BC path and the offshore portion of the jet. The values of the barotropic conversion term (BTC) are highest in the surface layers and decreased with depth, whereas the values of the baroclinic conversion term (BCC) and the vertical eddy heat flux (VEHF) are highest in the subsurface. Despite the vertical thickening of the BC, the highest energy conversion rates are confined to the upper 700 m of the water column. The energetic analysis showed that the current features mixed instability processes. The vertical weighted mean of the BTC and BCC presented an oscillatory pattern related to the bathymetry. The eddy field accelerates the time‐mean flow upstream and downstream of bathymetric features and drains energy from the time‐mean flow over the features. The BC is baroclinically unstable south of 28°S, and the highest energy conversion rates occur in Cabo de São Tomé, Cabo Frio, and the Cone do Rio Grande. First three‐dimensional energetics of eddy‐mean flow interactions in the Brazil CurrentFirst investigation of Brazil Current dynamics south of 28°S, region whose there an important bathymetric feature called Cone do Rio GrandeThe Brazil Current is baroclinically unstable throughout its path and marked by baroclinic instability process |
Plný text