| 摘要: |
| 新生代以来澳大利亚板块向北漂移了~20°，气候也随之发生了明显改变，即其北部逐渐进入了热带辐合带的影响范围，与亚欧大陆间的联系越来越紧密。上新世时印度尼西亚贯穿流的流通性受到限制，这可能直接促成了澳大利亚季风的形成。海洋沉积记录显示，澳大利亚气候的季节性特征最早出现于~3.5 Ma，而现代意义上的澳大利亚季风则形成于~2.4 Ma。第四纪阶段的澳大利亚季风表现出明显的轨道周期：冰期（间冰期）时夏季风减弱（加强），其演化主要受控于北半球日射量、东亚冬季风的跨赤道作用、表层海水温度与海平面高度变化。在更短的时间尺度上，末次冰期以来的澳大利亚季风则具有与北半球高纬度地区典型气候事件相似的千年周期，大致表现为：北半球的丹斯伽阿德—厄施格尔（Dansgaard/Oeschger）暖期对应着澳大利亚夏季风强度的减弱，而北半球的海因里希（Heinrich stadials）与新仙女木（Younger Dryas）冷事件时澳大利亚夏季风增强。但马来群岛不同地区的上述古气候记录之间存在差异，这可能与区域性因素的影响有关。季风降水的千年尺度变化与热带辐合带的位置密切相关，且其相位变化与同纬度的非洲和南美洲古季风截然不同，明显响应了北半球日射量，这可能与亚洲季风系统的跨赤道作用有关。末次冰期古生产力研究表明，在班达海与澳大利亚西北沿海，澳大利亚季风可以通过影响洋流模式、陆表降水与径流，来控制陆源物质向海洋的输送、海水结构的稳定性以及表层海水过程，进而影响海洋生物生产力。 |
| 关键词: 澳大利亚古季风 演化历史 控制因素 生产力 |
| DOI：10.11693/hyhz20200600185 |
| 分类号: |
| 基金项目:中国科学院战略性先导科技专项（B类），XDB42000000号；国家自然科学基金，41676038号，41876034号。 |
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| EVOLUTION OF AUSTRALIAN PALEOMONSOON AND ITS CONTROLLING FACTORS AND EFFECT ON MARINE PRODUCTIVITY |
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XU Zhao-Kai1,2,3,4, SUN Tian-Qi1,5, CHANG Feng-Ming1,2,3
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1.Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;2.Laboratory for Marine Geology, Pilot National Laboratory for Marine Science and Technology(Qingdao), Qingdao 266061, China;3.Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China;4.CAS Center for Excellence in Quaternary Science and Global Change, Xi'an 710061, China;5.University of Chinese Academy of Sciences, Beijing 100049, China
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| Abstract: |
| Since the Cenozoic, the Australian Plate has drifted about 20 latitudes to the north, and its climate also underwent significant changes. When northern Australia was gradually moved into the control of the Intertropical Convergence Zone, its connection with Eurasia also increased. In the Pliocene, the Indonesian Throughflow was limited, which started the Australian paleomonsoon. Marine sedimentary records show that the climate of Australia seasonal character appeared first at ~3.5 Ma. In addition, the Australian monsoon in the present sense had been ultimately built at ~2.4 Ma. The Australian monsoon had obvious orbital cycles in Quaternary. The summer monsoon in the glacial period weakened and the interglacial period strengthened, which was mainly affected by the insolation of the Northern Hemisphere, the transequatorial action of East Asian Winter Monsoon, the surface sea water temperature of the eastern Indian Ocean, and the fluctuation of global sea level. The Australian monsoon had millennium cycles similarly to climatic events in the high latitude of Northern Hemisphere in the last deglaciation. In the Dansgaard/Oeschger event when the Northern Hemisphere was warm, summer monsoon weakened; In the Heinrich Stadials and the Younger Dryas events when the Northern Hemisphere was cool, the Australian summer monsoon strengthened. On the millennium timescales, the change of summer monsoon rainfall was closely related to the position of the Intertropical Convergence Zone. Moreover, the change of Australian monsoon was in anti-phase with the paleomonsoon records in the same latitude of Africa and South America, responding to the Southern Hemisphere insolation. Australian monsoon obviously responded to the insolation of the Northern Hemisphere. This inverse phased relationship might be related to the transequatorial interaction between the Asian monsoon and Australian monsoon. According to the studies on paleoproductivity of the last glacial period, the Australian monsoon played an important role on the marine biological productivity. The Australian monsoon can control the terrigenous input to the ocean, the structural stability of seawater, and the processes occurring at the sea surface by affecting the current patterns, precipitation, and runoff. |
| Key words: Australian paleomonsoon evolution controlling factors productivity |
