Strong asymmetry of hemispheric climates during MIS-13 inferred from correlating China loess and Antarctica ice records
Strong asymmetry of hemispheric climates during MIS-13 inferred from correlating China loess and Antarctica ice records
复制标题
根据中国黄土和南极洲冰记录的关联推断 MIS-13 期间半球气候的强烈不对称性
DOI：
10.5194/cp-5-21-2009
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发表时间：
2009-01-01
影响因子：
4.3
通讯作者：
Qin, L.
中科院分区：
文献类型：
--
作者：
Guo, Z. T.;Berger, A.;Qin, L.
抽象的。我们将中国黄土和南极洲冰记录关联起来，以解决过去 800 ka 的半球间气候联系。结果显示亚洲和南极气候在冰期-间冰期尺度上存在广泛的耦合。然而，许多脱钩的方面被揭示出来，其中海洋同位素阶段（MIS）13与其他间冰期相比表现出强烈的异常。其特点是世界海洋中底栖氧 (δ18O) 和碳同位素 (δ13C) 值异常正值、南极温度较低、南大西洋夏季海面温度较低、二氧化碳和甲烷浓度较低，但亚洲、印度和非洲夏季风极强，亚洲冬季风最弱，亚洲尘埃和铁通量最低。北部高纬度地区的记录也证明了普遍的温暖条件。这些一致表明北半球较温暖，南半球较凉爽，因此 MIS-13 期间半球气候存在强烈的不对称性。 MIS-11 和 MIS-5e 期间也发生了较小程度的类似异常。因此，MIS-13 提供了一个案例，即北半球在温室气体浓度相对较低的情况下经历了大幅变暖。它表明全球气候系统具有自然变异性，无法通过北方夏季日照和大气二氧化碳变化的简单反应来预测。 MIS-13期间，两个半球以不同的方式做出反应，导致全球范围内出现异常的大陆、海洋和大气状况。这些相关性还表明，海洋δ18O记录并不总是北方冰量变化的可靠指标，半球气候的不对称性是控制亚洲、印度和非洲季风环流强度的重要因素之一，很可能是通过调节热带辐合带（ITCZ）的位置和海陆热力对比来实现的。
Abstract. We correlate the China loess and Antarctica ice records to address the inter-hemispheric climate link over the past 800 ka. The results show a broad coupling between Asian and Antarctic climates at the glacial-interglacial scale. However, a number of decoupled aspects are revealed, among which marine isotope stage (MIS) 13 exhibits a strong anomaly compared with the other interglacials. It is characterized by unusually positive benthic oxygen (δ18O) and carbon isotope (δ13C) values in the world oceans, cooler Antarctic temperature, lower summer sea surface temperature in the South Atlantic, lower CO2 and CH4 concentrations, but by extremely strong Asian, Indian and African summer monsoons, weakest Asian winter monsoon, and lowest Asian dust and iron fluxes. Pervasive warm conditions were also evidenced by the records from northern high-latitude regions. These consistently indicate a warmer Northern Hemisphere and a cooler Southern Hemisphere, and hence a strong asymmetry of hemispheric climates during MIS-13. Similar anomalies of lesser extents also occurred during MIS-11 and MIS-5e. Thus, MIS-13 provides a case that the Northern Hemisphere experienced a substantial warming under relatively low concentrations of greenhouse gases. It suggests that the global climate system possesses a natural variability that is not predictable from the simple response of northern summer insolation and atmospheric CO2 changes. During MIS-13, both hemispheres responded in different ways leading to anomalous continental, marine and atmospheric conditions at the global scale. The correlations also suggest that the marine δ18O record is not always a reliable indicator of the northern ice-volume changes, and that the asymmetry of hemispheric climates is one of the prominent factors controlling the strength of Asian, Indian and African monsoon circulations, most likely through modulating the position of the inter-tropical convergence zone (ITCZ) and land-sea thermal contrasts.