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印尼穿越流连接西太平洋和印度洋,调节这两个大洋之间的热量和水汽的交换,继而在全球气候变化中扮演着重要的角色.印尼穿越流的通量、水体性质和垂向分层受东亚季风和厄尔尼诺-南方涛动(El Nio-Southern Oscillation,ENSO)等气候现象强烈影响.本文研究了钻取于帝汶海区印尼穿越流出口处SO18462孔的沉积物,分析浮游有孔虫表层水种和温跃层水种壳体的氧同位素和Mg/Ca比值,恢复了末次冰期以来印尼穿越流表层水和温跃层水的温度和盐度以及垂向温度梯度的变化,并与钻取于西太平洋暖池中心的3c BX孔记录进行了对比.结果显示,末次冰期时帝汶海与西太平洋暖池的表层海水性质几乎一致,自大约16 ka以来帝汶海相对暖池的表层海水淡化显著,但二者之间的温度差异变化不大.冰消期时,帝汶海和暖池温跃层海水温度均呈现升高趋势,在大约11.5 ka达到峰值;之后,暖池中心的温跃层海水温度总体维持不变,而帝汶海的温跃层海水温度逐渐降低;6 ka以来,帝汶海和暖池温跃层海水性质总体趋于一致.上述结果表明,早全新世(11.5~6 ka),类拉尼娜状态以及东亚夏季风降水的增加,使得区域内表层海水盐度降低,抑制了印尼穿越流表层流,导致温跃层流加强.6 ka以来,除了东亚冬季风影响下最终造成帝汶海温跃层变浅外,ENSO的频繁活动也可能是重要的影响因素.
Indonesia flows through the West Pacific and Indian Oceans to regulate the exchange of heat and water vapor between these two oceans, and thus plays an important role in global climate change. The fluxes, the nature of the water bodies and the vertical stratification The East Asian monsoon and the El Nio-Southern Oscillation (ENSO) are strongly influenced by the climate phenomena such as the sediments drilled from SO18 462 holes in Indonesia through the outlet of Timor Sea, The oxygen isotope and Mg / Ca ratios of surface water species and thermocline water husk species restored the changes of temperature and salinity and vertical temperature gradient of surface water and thermocline water in Indonesia since the last ice age, A comparison of the records of 3c BX boreholes drilled in the West Pacific Warm Pool Center shows that the surface seawater properties of the Timor Sea and the western Pacific warm pool are nearly identical during the last glacial period, The surface seawater desalination is significant, but the temperature difference between the two has little change.When the ice disappears, the sea temperature in the Timor Sea and the thermocline shows an upward trend, reaching a peak at about 11.5 ka. After that, the warm pool The temperature of the thermocline seawater in the heart generally remains the same while the temperature of the thermocline seawater in the Timor Sea gradually decreases. Since 6 ka, the thermocline waters in the Timor Sea and the warm pool generally converge. The above results show that, During the Holocene (11.5 ~ 6 ka), the La Niña-like state and the increase of precipitation in the East Asian summer monsoon, the salinity of the surface seawater in the region decreased, which restrained the stratigraphic flow across the surface of Indonesia and resulted in the strengthening of the thermocline. Since 6 ka, Under the influence of the winter monsoon, which ultimately leads to a decrease in the sea surface thermocline of the Timor Sea, frequent ENSO activities may also be important influencing factors.