Subtropical South African hydroclimate during the mid-Piacenzian Warm Period recorded by fynbos vegetation as a test case for climate model performance

点击翻译按钮获取中文摘要

The late Pliocene period between 3.264 and 3.025 Ma called mid-Piancenzian Warm Period (mWPW) is extensively studied by modelers and palaeoclimatologists because it presents a geologic analogue for future warming. Data-model comparisons reveal a mismatch between climate model predictions and palaeorecords: Many climate models predict drier subtropical regions during warm periods with enhanced atmospheric carbon dioxide concentrations, whereas palaeorecords of the mWPW indicate wetter subtropical regions. However, the available palaeorecords are concentrated on the northern hemisphere and there are no high temporal resolution records for the southern hemisphere. To fill this gap, I propose a study of orbital resolved fluctuations during the mWPW of South African subtropical hydroclimate registered by the pollen from fynbos vegetation in deep-sea marine sediments recovered southwest from Cape Town. The relative importance of two different forcing mechanisms on the climate of subtropical South African will be tested. On one hand, the influence of changes in sea surface temperatures along the west coast of South Africa related to the strength and position of the South Atlantic High. On the other hand, the effect of changes in the latitude of the Antarctic Subtropical Front and associated west wind drift.