末次间冰期以来古黑潮演化及其对气候变化的作用

EVOLUTION OF THE PALEO-KUROSHIO SYSTEM AND ITS RELATION TO CLMATE CHANGES SINCE THE LAST INTERGLACIAL

西太平洋边缘海区作为联接大陆与深水大洋气候记录的桥梁，这种纽带关系使得边缘海区成为理解、研究过去全球变化和古海洋学诸因素变化的理想区域之一。同时，边缘海区也是大洋与大气进行热量交换的重要区域。黑潮流系不仅控制了该区的物理海洋学特征，同时也对东亚大陆气候施加了巨大影响。通过边缘海区，黑潮向东北日本沿海输送了大量高温、高盐水体，并产生强烈的海－气相互作用。因此这一变化过程对于我们了解过去区域性及全球性气候变化历史是非常重要的。本文着重研究黑潮流域古海水表面温度变化以及相应的１２万年以来物理海洋特征。目的在确定末次盛冰期时古黑潮流域模式以及海陆气候相互作用。对贯穿大部分黑潮流域的数个柱状沉积物样品进行了浮游有孔虫种群分析，氧同位素分析，生物地层学分析以及有孔虫种群转换函数分析。研究结果显示，冰期时海水表层水温季节性变化幅度要远大于间冰期，特别是在末次盛冰期时尤为明显，说明陆地冬季季风对这种反差具有很大影响。对海水表层水温变化分析表明，末次盛冰期时边缘海区的温度下降幅度变化比邻近大洋要大２倍左右，而且与现今温度差别由南向北逐渐增大，这与冬季季风影响由南向北逐渐加强是全完一致的，可以认为西太平洋边缘海区在末次盛冰期时?

Western Pacific marginal seas act as a bridge to connect continent and deep oceanclimate records.This link makes marginal seas one of the most suitable areas for improv-ing our understanding of past global climatic and oceanographic changes,A large propor-tion of heat exchanges between atmosphere and ocean also occurs at marginal seas.The Kuroshio current system not only controls the oceanography of the areathrough which it flows but also influences the climatic patterns of the East Asian conti-nent.It transports large volumes of warm salty water to the northeast along themarginal seas and the coast of Japan,resulting in the development of strong air-sea in-teractions in these regions. These interactions play an important role in understandingregional and global climatic change history.The present study of the Kuroshio current focuses on sea surface temperature varia-tion and its relationship to the oceanographic conditions during the last 120, 00 years.Our objective is to examine the shift in the path of the Kuroshio and the interaction be-tween land and sea during the last glacial maximum(LGM).Total faunal analysis ofplanktonic foraminifera,stable oxygen isotopes and paleotemperature estimates viatransfer function were carried out on 4 cores. The resulting sea surface temperature vari-ations throughout the last 120kaB.P. provides us with a fundamental understanding ofthe paleo-oceanographic evolution of the Kuroshio region.