Holocene ITCZ and Indian monsoon dynamics recorded in stalagmites from Oman and Yemen (Socotra)
Holocene ITCZ and Indian monsoon dynamics recorded in stalagmites from Oman and Yemen (Socotra)
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DOI：
10.1016/j.quascirev.2006.04.012
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发表时间：
2007-01-01
影响因子：
4
通讯作者：
Matter, Albert
中科院分区：
文献类型：
--
作者：
Fleitmann, Dominik;Burns, Stephen J.;Matter, Albert
阿曼北部和南部以及也门（Socotra） 4个洞穴全新世石笋的高分辨率氧同位素（δ O-18）剖面提供了从北纬12度到北纬23度的纬向样带降水波动的详细信息。δ O-18值反映了降水的数量，降水主要受ITCZ的平均纬向位置和印度夏季风（ISM）的动力控制。在全新世早期，6180值的快速下降表明夏季ITCZ和相关ISM雨带的平均纬向位置快速北移，季风降水的年代际到百年尺度变化与格陵兰冰芯记录的高纬温度变化具有良好的相关性。全新世中后期夏季ITCZ持续南移，季风降水随太阳日照减少而逐渐减少，这一趋势在印度和东亚风域的其他季风记录中也有体现。重要的是，没有证据表明季风降水在全新世中期突然减弱。虽然在所有季风记录中都有明显的季风突变事件，但它们都是短暂的，并且明显叠加在季风降水减少的长期趋势上。在全新世晚期，阿曼的ISM降水与索科特拉的季风间（春/秋）降水之间存在反相关，表明至少4.5 ka BP以来夏季风季持续时间可能存在长期变化。在季风季逐渐缩短、夏季平均ITCZ逐渐南退和季风减弱的共同作用下，位于印度和亚洲季风域北部边缘的地区降水总量减少，而靠近赤道的地区降水总量增加。(c) 2006 Elsevier Ltd.版权所有。
High-resolution oxygen isotope (delta O-18) profiles of Holocene stalagmites from four caves in Northern and Southern Oman and Yemen (Socotra) provide detailed information on fluctuations in precipitation along a latitudinal transect from 12 degrees N to 23 degrees N. delta O-18 values reflect the amount of precipitation which is primarily controlled by the mean latitudinal position of the ITCZ and dynamics of the Indian summer monsoon (ISM). During the early Holocene rapidly decreasing 6180 values indicate a rapid northward displacement in the mean latitudinal position of the summer ITCZ and the associated ISM rainfall belt, with decadal- to centennial-scale changes in monsoon precipitation correlating well with high-latitude temperature variations recorded in Greenland ice cores. During the middle to late Holocene the summer ITCZ continuously migrated southward and monsoon precipitation decreased gradually in response to decreasing solar insolation, a trend, which is also recorded in other monsoon records from the Indian and East Asian monsoon domains. Importantly, there is no evidence for an abrupt middle Holocene weakening in monsoon precipitation. Although abrupt monsoon events are apparent in all monsoon records, they are short-lived and clearly superimposed on the long-term trend of decreasing monsoon precipitation. For the late Holocene there is an anti-correlation between ISM precipitation in Oman and inter-monsoon (spring/autumn) precipitation on Socotra, revealing a possible long-term change in the duration of the summer monsoon season since at least 4.5 ka BP. Together with the progressive shortening of the ISM season, gradual southward retreat of the mean summer ITCZ and weakening of the ISM, the total amount of precipitation decreased in those areas located at the northern fringe of the Indian and Asian monsoon domains, but increased in areas closer to the equator. (c) 2006 Elsevier Ltd. All rights reserved.