Seasonal and interannual variability of the Brazil - Malvinas front: an altimetry perspective
Event: 2015 Ocean Surface Topography Science Team Meeting
Session: Science III: Large scale and global change ocean processes: the ocean's role in climate
Presentation type: Type Poster
The Brazil and Malvinas Confluence in the Southwestern Atlantic is one of the most energetic regions of the world ocean. Using recent measurements of sub-surface velocity currents, collected along 2348 nautical miles with a vessel mounted acoustic Doppler profiler onboard R/V BIO Hespérides, we validate geostrophic velocities derived from gridded fields of sea surface height (SSH). A remarkable correspondence between in-situ surface hydrographic data collected from the vessel and satellite sea surface temperature (SST), color and altimetry data allows selecting a specific SSH contour to track the position of the Brazil-Malvinas front. We then use 21 years of SSH data distributed by AVISO to show that the Brazil-Malvinas front shows a NS orientation in winter and a NE-SW orientation in summer, in good agreement with results based on the analysis of nine years of SST gradients. Furthermore, a clear southward migration of the front during the 21 year period is observed. The migration is associated with the southward shift of the South Atlantic high-pressure system that is in turn related to large climate changes in the southern portion of the South American continent.