Subproject 3 (SP 3): Upwelling filaments near Lüderitz and their interaction with the South Atlantic eastern boundary circulation

SP 3 (Quadfasel/Jochumsen, ZMAW, Hamburg) investigates the offshore spreading of upwelling filaments near Lüderitz (Namibia), and their interaction with the South Atlantic Subtropical Gyre. The processes relevant for the formation, extent and lifetime of the filaments will be addressed in this process study composed of two field campaigns that will be carried out in close cooperation with SP 1 and SP2.

Goals:

• Detailed physical examinations of upwelling filaments will be carried out on a research cruise during the Lüderitz upwelling season in boreal fall 2013. A short term mooring array will be deployed, aimed at capturing submesoscale variability induced by filaments. The cruise will include contributions from IOW and GEOMAR, using various devices for physical measurements (e.g. CTD, ADCP, Glider (GEOMAR), microstructure measurements (IOW)).
  
  
• Results from the cruise and the moorings in conjunction with satellite products (SST, wind data) will allow us to identify the processes governing the formation periods, structure and decay of upwelling filaments. Additionally, the mooring array will provide the first time series of submesoscale filament variability near Lüderitz.
  
  
• The data will complement the observations carried out in the GENUS project, where the focus is on northern upwelling filaments at the shelf edge. The offshore dynamics are expected to differ, since interaction of filaments with the Benguela Current or Agulhas Current Rings are only likely in the southern region near Lüderitz.

The improved understanding of filament dynamics will contribute to assessing the modeling errors (in cooperation with SP2 and SP4).