Isopollen maps for 18,000 years B.P. of the offshore of Northwest Africa: Evidence for paleowind circulation

Distribution patterns of the most important pollen types from southern European and northwest African source areas for the 18,000 years B.P. time slice are reconstructed from pollen records of 14 well-dated deep-sea cores located between 37° and 9°N and compared with the modern pollen distribution in this area. It is concluded that the belt with maximum African Easterly Jet transport did not shift latitudinally during the last glacial-interglacial transition but remained at about 20°N. Furthermore, it is substantiated that the trade winds did not shift latitudinally during the last glacial-interglacial transition. This evidence is not compatible with an atmospheric circulation model that assumes a zone of surface westerlies in the northern part of northwest Africa. Trade winds during glacial episodes did, however, intensify, especially from about 36° to 24° N.

针对距今18000年（18,000 years B.P.）的时段，研究基于分布于北纬37°至9°海域的14根定年精准的深海岩芯的花粉记录，重建了源自南欧与西北非物源区的主要花粉类型的分布格局，并将该重建结果与该区域的现代花粉分布进行对比。研究得出结论：在末次冰期-间冰期过渡阶段，非洲东风急流（African Easterly Jet）输送最强的纬向带并未发生纬向偏移，而是稳定维持在北纬20°附近。此外，研究证实，在末次冰期-间冰期过渡阶段，信风（trade winds）并未发生纬向偏移。该证据与假设西北非洲北部存在近地面西风带的大气环流模型并不兼容。不过，冰期时段的信风强度有所增强，尤其在北纬36°至24°区间内表现显著。