| Change of Indonesian Throughflow outflow in response to East Asian Monsoon and ENSO activities since the Last Glacial |
| |
| 作者姓名： | XU Jian |
| |
| 基金项目： | jointly supported by National Natural Science Foundation of China(Grant No.41176044);The German Research Foundation(Grant No.KU649/28-1);Specialized Research Fund for the Doctoral Program(Grant No.20096101120025);State Key Laboratory of Continental Dynamics(Grant No.BJ12139) |
| |
| 摘 要： |
|
Change of Indonesian Throughflow outflow in response to East Asian monsoon and ENSO activities since the Last Glacial |
| |
| XU Jian.Change of Indonesian Throughflow outflow in response to East Asian Monsoon and ENSO activities since the Last Glacial[J].Science China Earth Sciences,2014,57(4):791-801. |
| |
| Authors: | Jian Xu |
| |
| Institution: | 1. Institute of Cenozoic Geology and Environment, State Key Laboratory of Continental Dynamics and Department of Geology, Northwest University, Xi’an, 710069, China
2. Institute for Geosciences, Kiel University, D-24118, Kiel, Germany
|
| |
| Abstract: | The Indonesian Throughflow (ITF) links upper ocean waters of the west Pacific and Indian Ocean, modulates heat and fresh water budgets between these oceans, and in turn plays an important role in global climate change. The climatic phenomena such as the East Asian monsoon and El Niño-Southern Oscillation (ENSO) exert a strong influence on flux, water properties and vertical stratification of the ITF. This work studied sediments of Core SO18462 that was retrieved from the outflow side of the ITF in the Timor Sea in order to investigate response of the ITF to monsoon and ENSO activities since the last glacial. Based on Mg/Ca ratios and oxygen isotopes in shells of planktonic foraminiferal surface and thermocline species, seawater temperatures and salinity of both surface and thermocline waters and vertical thermal gradient of the ITF outflow were reconstructed. Records of Core SO18462 were then compared with those from Core 3cBX that was recovered from the western Pacific warm pool (WPWP). The results displayed that similar surface waters occurred in the Timor Sea and the WPWP during the last glacial. Since ～16 ka, an apparent difference in surface waters between these two regions exists in salinity, indicated by much fresher waters in the Timor Sea than in the WPWP. In contrast, there is little change in difference of sea surface temperatures (SSTs). With regard to thermocline temperature (TT), it increased until ～11.5 ka since the last glacial, and then remained an overall unchanged trend in the WPWP but continuously decreased in the Timor Sea towards the late Holocene. Since ～6 ka, thermocline waters have tended to be close to each other in between the Timor Sea and the WPWP. It is indicated that intensified precipitation due to East Asian monsoon and possible ENSO cold phase significantly freshened surface waters over the Indonesian Seas, impeding the ITF surface flow and in turn having enhanced thermocline flow during the Holocene. Consequently, thermocline water of the ITF outflow was cooling and thermocline was shoaling towards the late Holocene. It is speculated that, in addition to strengthening of East Asian winter monsoon, increasing ENSO events during the late Holocene likely played an important role in influencing thermocline depth of the ITF outflow. |
| |
| Keywords: | seawater properties depth of thermocline Indonesian Throughflow East Asian Monsoon ENSO |
| 本文献已被 CNKI SpringerLink 等数据库收录！ |
|
