Astronomically forced variations in western African rainfall (21°N–20°S) during the Last Interglacial period
Astronomically forced variations in western African rainfall (21°N–20°S) during the Last Interglacial period
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DOI：
10.1002/2013gl058999
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发表时间：
2014-03
影响因子：
5.2
通讯作者：
A. Govin;V. Varma;M. Prange
中科院分区：
文献类型：
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作者：
A. Govin;V. Varma;M. Prange
这项研究记录了末次间冰期（LIG）期间西非降水的长期演变。我们比较了从西非边缘的9个沉积物岩心获得的地球化学记录与海洋大气环流模型和太阳辐射作为唯一强迫进行的瞬态模拟（130-115 ka）。代理记录和模式输出之间的良好一致性表明，西非降水的长期变化在很大程度上响应于LIG大部分时间内的日照变化。在LIG早期干燥阶段（与高纬度冰山融化或测年不确定性有关）之后，北方夏季日照控制了127至122 ka之间北非季风的增强，可能促进了人类从非洲迁移。赤道非洲降雨量略有增加整个LIG响应增加年日照。10-20°S的东西对比降雨演变说明了南部非洲对太阳辐射强迫的复杂响应，与北部和赤道西部非洲的更直接响应相反。
This study documents the long‐term evolution of western African precipitation during the Last Interglacial (LIG). We compare geochemical records obtained on nine sediment cores from the western African margin to a transient simulation (130–115 ka) performed with an ocean‐atmosphere general circulation model and insolation as sole forcing. Good agreement between proxy records and model outputs indicates that long‐term changes in western African precipitation largely responded to insolation variations during most of the LIG. After an early LIG dry phase (related to high‐latitude iceberg melting or dating uncertainties), boreal summer insolation controlled the intensification of the North African monsoon between 127 and 122 ka, perhaps facilitating human migrations out of Africa. Equatorial African rainfall slightly increased throughout the LIG in response to increasing annual insolation. East‐west contrasting rainfall evolutions at 10–20°S illustrate the complex southern African response, in contrast to more direct responses of North and equatorial western Africa, to insolation forcing.