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

海洋环流，特别是大西洋经向翻转环流(MOC)对全球气候有很大的影响，无论是在高纬度还是低纬度。然而，热带地区的作用还存在争议。针对冰期热带变率的高分辨率研究很少，因为当时MOC发生了很大的变率。我们希望通过一项关于热带非洲气候和植被发展的高分辨率研究来弥合这一差距，方法是对安哥拉海岸外海洋钻探计划1078号站点的海洋沉积物进行孢粉学研究。安哥拉植被在冰期(海因里希事件)期间几个气候突变时期的反应和反馈应有助于洞察南部热带MOC变异性的影响以及气候扰动在大气中的快速传播。地球系统-气候模型的使用将使我们能够研究特定风场模式下植被覆盖的动态。在分析模型结果时，我们的重点将放在西非和南美洲东部诱发的降水异常和植物功能类型/生物群的变化上。模型数据的比较将依赖于文献数据和我们自己获取的安哥拉植被在几次海因里希事件期间的变化数据。我们希望测试热带辐合带的纬度位置和迁移在MOC部分或完全关闭期间对热带非洲气候的影响。

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.