Pollen analyses of sediment core GeoB1711-4 in the eastern South Atlantic

Influx of aeolian pollen trapped in marine sediments off Namibia provides a wind variation record for the last 135 kyr. The influx of major pollen components is derived from the southwest African desert/semi-desert zone and shows six periods during which enhanced southeast trade winds contributed to strong upwelling and reduced sea surface temperatures. The most prominent of these occurred during 17-23 cal. kyr, 42-56 kyr and before 130 kyr B.P. Correspondence between the pollen influx record and the Vostok deuterium isotope record suggests that pronounced glacial Antarctic cooling was accompanied by intensification of the southeast trades throughout the Late Quaternary. However, during 42-23 kyr B.P. the combination of strong Antarctic glaciation with a decrease of wind zonality induced by low latitude precessional insolation changes caused strong alongshore winds and Ekman pumping that resulted in strong upwelling and reduced sea surface temperatures without pollen influx enhancement.纳米比亚近海海洋沉积物中封存的风成花粉（aeolian pollen）通量，为过去135千年（kyr）提供了一套完整的风速变化记录。其主要花粉组分的通量源自西南非洲沙漠/半沙漠带（southwest African desert/semi-desert zone），记录显示存在六个时段，在此期间增强的东南信风（southeast trade winds）助推了强烈上升流（upwelling），并导致海表温度（sea surface temperatures）降低。其中最为显著的三个时段分别为17~23校准千年（cal kyr）、42~56校准千年以及距今130千年之前。风成花粉通量记录与沃斯托克（Vostok）氘同位素记录之间的对应关系表明，晚第四纪（Late Quaternary）以来，南极冰期的显著降温过程均伴随东南信风的增强。然而在距今42~23千年期间，强烈的南极冰盖发育叠加低纬度岁差日射变化（low latitude precessional insolation changes）引发的风带性（wind zonality）减弱，催生了强劲的沿岸风与埃克曼抽吸（Ekman pumping），最终引发强烈上升流与海表温度降低，但该时段内风成花粉通量并未出现增强。