Climate development and vegetation feedbacks in tropical Africa during Heinrich events (data - model comparison)

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The ocean circulation, in particular the Atlantic meridional overturning circulation (MOC) has a strong impact on global climate, both at high and low latitudes. However, the role of the tropics is debated. High resolution studies aiming at tropical variability of the glacial period, when much variability in the MOC occurred, are scarce. We want to bridge this gap with a high resolution study on climate and vegetation development in tropical Africa by means of palynology on marine sediments of Ocean Drilling Program Site 1078 off the coast of Angola. The response and feedbacks of the vegetation in Angola during several periods of abrupt climate change during the glacial (Heinrich events) should provide insight in the impact of MOC variability in the southern tropics and the rapid propagation of climatic disturbances through the atmosphere. The use of an Earth system-climate model will allow us to study the dynamics of the vegetation cover for specific wind field patterns. In analyzing the model results, our focus will be on the induced precipitation anomaly and shifts in plant-functional types/biomes in western Africa and eastern South America. Model-data comparisons will rely on literature data and our own data acquisition ofthe Angolan vegetation variability during several Heinrich events. We want to test the influence of the latitudinal position and migration of the Intertropical Convergence Zone on the climate of tropical Africa during periods of partial or complete MOC shut-down.