Western boundary circulation, AMOC, Tropical Instability WaVES

• Applicant: Professor Dr. Peter Brandt
• Subject Area: Oceanography
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 567292779

The planned research cruise has two main objectives:1) To determine intraseasonal to decadal variations in circulation and water masses in the tropical Atlantic.2) To gain a better understanding of the role of tropical instability waves (TIWs) in ocean-atmosphere interactions, biological productivity, and carbon export to the deep ocean.The first objective will be achieved through the exchange of long-term observatories at three locations: at the continental slope off the Brazilian coastat 11°S, at the equator at 23°W, and north of the Cape Verde archipelago at the Cape Verde Ocean Observatory (CVOO). Shipboard measurements along ~11°S using CTD/O₂/lADCP/UVP stations, as well as continuous measurements with shipboard ADCPs, will complement the moored observations at the western boundary and help identify long-term changes in water masses. Additional station measurements at the equator and CVOO, along with current measurements using shipboard ADCPs along 23°W, across the equator to Cape Verde, will further expand the database of long-term observatories in the tropical Atlantic.The second objective will be achieved through an interdisciplinary process study in regions with strong temperature and productivity fronts. Mesoscale variability in the form of TIWs, propagating along the front between cold equatorial upwelling water and warmer water to the north, generates submesoscale variability through instability processes. This variability affects wind fields and heat fluxes, triggers local mixing events, upwelling, and subduction at the fronts, and can temporarily enhance carbon export to deeper layers.As part of this process study, which is planned in the area between 23°W and 12°W, slightly north of the equator, physical, chemical, and biological data will be collected using shipboard measurements, gliders, and freely drifting instruments to improve our understanding of the frontal dynamics of TIWs and their consequences.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 2520: Infrastructure area - Research Vessels
• International Connection: USA
• Co-Investigators: Dr. Rebecca Hummels; Professor Dr. Rainer Kiko
• Cooperation Partner: Dr. Franz Philip Tuchen