METEOR M189

In the past decades, the tropical Atlantic climate experienced pronounced shifts. The related oceanic changes were largest in the eastern boundary upwelling systems. However, the impact of the regional climate change is complex and not fully understood. The major aim of the project related to the METEOR expedition M189, the BMBF-collaborative project “Benguela Niños: Physical processes and long-term variability (BANINO)” is to enhance and service the ocean observing system off southwest Africa aimed at studying the variability of the eastern boundary circulation and upwelling on time scales from subseasonal to decadal. Another cruise-related project, the EU-collaborative project „Tropical and South Atlantic climatebased marine ecosystem predictions for sustainable management (TRIATLAS)“ aims at assessing the status of the South and Tropical Atlantic marine ecosystem and developping a framework for predicting its future changes. The main objective of the measurement programme is to observe the variability of the eastern boundary circulation and upwelling on time scales from subseasonal to decadal. A focus of the measurement programme is to investigate the physical processes relevant for upwelling variability and its consequences for trace gas emissions and biological productivity. The processes include variability of wind-driven upwelling, variability of tidally generated internal waves and mixing on the continental slope and shelf, riverine freshwater input and precipitation, and frontal dynamics at the Angola-Benguela frontal zone. Another focus is on biogeochemical studies related to the sulfur cycle with respect to toxic sulfide events.