M148 cruise (2018): Belem (BR) to Walvis Bay (NA)
Physical oceanography study in the tropical South Atlantic at 11°S and in the eastern boundary upwelling region off Angola was carried during the research cruise on FS Meteor in May/June 2018.
The cruise combined the foci of the BMBF collaborative projects “Southwest African Coastal Upwelling System and Benguela Niños II (SACUS)” and “Regional Atlantic Circulation and Global Change (RACE II)”.
The major goals of the cruise were (1) to quantify the variability of eastern boundary current transports and the variability of the advection of anomalous water masses along the eastern boundary in conjunction with wave propagation along the coastal wave guides; (2) carry out a 4-day process study to elucidate the mechanism sustaining upwelling off Angola during the austral win-ter season; and (3) to determine the strength of the Atlantic meridional overturning circulation at 11.5°S.
The working programme involves the recovery and redeployment of moorings and bottom shields off Angola, deployments and recoveries of autonomous observatories (Gliders), microstructure measurements, and hydrographic sampling along 4 transects in the central and eastern tropical South Atlantic. Salinity, oxygen and nutrient concentrations as well as their isotopic composition will be determined from water samples.
Continuous underway observations were carried out with the thermosalinograph to measure temperature and salinity as well as trace gas concentrations (N2O, CO, O2 CO2) at the sea surface. Ocean velocity in the upper 1000m was also continouly measured using the two shipboard ADCPs (OS 38kHz, OS 75kHz).
In addition to the scientific program, a capacity building program for scientists and graduate students from our African and other international project partner institutes was carried out.
Extracted from GEOMAR Expeditions
M159 cruise (2019): Recife (BR) to Mindelo (NA)
The research program of cruise M159 is a combination of observations of the BMBF collaborative research project RACE – Nordatlantik Synthesis, the Programme-Oriented Funding (POF) of GEOMAR and observations for the BMBF joint project REEBUS.
Within the framework of BMBF RACE – Nordatlantik Synthesis as well as the aims of POF GEOMAR, the aim of this cruise is to investigate the variability of the western boundary current system off South America as well as to estimate the variability of the Atlantic meridional overturning circulation (AMOC) at 11°S. A particular focus at the western boundary off Brazil will be on the transport variability of the North Brazil Undercurrent (NBUC) – as part of the AMOC and the subtropical cells (STCs) – on timescales from intraseasonal to decadal. These observations will be complemented with the observations obtained on the meridional section across the equator at 35°W especially with respect to the signal propagation and changes of water masses.
The main operations during M159 will be the recovery and redeployment of several deep sea moorings, station work and the data recovery of two moored pressure inverted echo sounders (PIES). For the station work mainly the combination of CTD and Lowered ADCP will be used. In addition, underway measurements of upper ocean currents with the two shipboard ADCPs, hydrographic measurements and with the thermosalino-graph probe will be performed.
The BMBF collaborative research project REEBUS aims at investigating the role of eddies in the carbon pump of eastern boundary upwelling systems. During M159, the main operations related to REEBUS will be the recovery and the deployment of the Cape Verde Ocean Observatory (CVOO), a deep-sea mooring located to the north of the Cape Verde islands.
Odilon Joël Houndegnonto (Africa)
Daniela Risaro (Latin America)
Marco Sandoval Belmar (Latin America)
Ramilla Vieire de Assunção (Latin America)
Fernanda DI Alzira Oliveira Matos (Latin America)
Felipe Ohade Lopes Branco (Latin America)
Juan Carbajal (Latin America)
Olusegun A. Dada (Africa)