Synchronous changes in the East Asian-Australian summer monsoons around 7.2 ka
Synchronous changes in the East Asian-Australian summer monsoons around 7.2 ka
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DOI：
10.1016/j.palaeo.2021.110303
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发表时间：
2021-04
期刊：
影响因子：
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通讯作者：
Wenchao Zhang;Maoxiang Chang;Hong Yan;J. Dodson;Guangxue Li
中科院分区：
文献类型：
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作者：
Wenchao Zhang;Maoxiang Chang;Hong Yan;J. Dodson;Guangxue Li
先前的证据已经确定，在全新世期间，东亚-澳大利亚夏季风（eaasm）在百年至千年的时间尺度上存在许多突变，这些突变与北纬高纬度冷却异常密切相关。然而，对7.2 ka事件的空间特征关注较少。本文系统地整合了东亚地区的一系列水文记录，以提高对7.2 ka前后东亚地区降水空间分布的认识。结果表明，在7.2 ka前后，中国北部地区干旱显著，而中国南部热带地区相对干旱或干湿转变，明显表明了7.2 ka事件期间东亚夏季风的突然崩溃。在澳大利亚夏季风区也观察到类似的模式。澳大利亚北部及其邻近海域的降水在7.2 ka左右突然减少，而在印度-太平洋暖池区中心附近的干湿转移中略有增加。因此，在7.2 ka事件中，东洋构造的同步塌陷似乎与8.2 ka事件中东洋构造的跷跷板不同。推断，在7.2 ka事件中，东亚副热带气旋的同步变化可能是对低太阳辐照度叠加火山喷发和ENSO活动影响的响应。
Previous evidence has identified the presence of numerous abrupt changes in the East Asian-Australian summer monsoons (EAASMs) on centennial to millennial timescales during the Holocene, which are tightly coupled with high northern latitude cooling anomalies. However, less attention has been paid to spatial characteristics in the EAASMs during the 7.2 ka event. Here a series of hydrological records from the EAASMs region are systematically integrated to improve understanding of the spatial precipitation distributions in the EAASMs region around 7.2 ka. The results show significant dry conditions in northern China, but relatively dry conditions or dry-to-wet shifts in southern tropical China around 7.2 ka, distinctly indicating an abrupt collapse of the East Asian summer monsoon during the 7.2 ka event. A similar pattern is also observed in the Australian summer monsoon region. The precipitation in northern Australia and its adjacent seas abruptly decreases around 7.2 ka, whereas it takes on a slight increase with a dry-to-wet shift near the center of the Indo-Pacific warm pool region. Therefore, it seems that synchronous collapse in the EAASMs occurs during the 7.2 ka event, which is different from a see-saw in the EAASMs during the 8.2 ka event. And it is inferred that synchronous changes in the EAASMs at the 7.2 ka event is probably a response to a low solar irradiance superimposed with influence of the volcanic eruption and ENSO activities.