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| 末次盛冰期太平洋赤道辐合带对暖池外热带海表温度变化的敏感性 | |
| 引用本文： | 王跃,翦知湣,赵平.末次盛冰期太平洋赤道辐合带对暖池外热带海表温度变化的敏感性[J].第四纪研究,2009,29(2):221-231. |
| 作者姓名： | 王跃 翦知湣 赵平 |
| 作者单位： | 1. 同济大学海洋地质国家重点实验室,上海,200092 2. 中国气象局中国气象科学研究院,北京,100081 |
| 基金项目： | 国家重点基础研究发展规划(973计划)，国家自然科学基金创新研究群体基金，中国大洋协会项目 |
| 摘 要： | 利用美国NCAR CAM3大气环流模式，分析了末次盛冰期（LGM）两个不同的热带海表温度重建方案中，北半球冬季热带中、西太平洋对流活动及大气环流对暖池外（赤道东太平洋和热带大西洋）热带SST异常的敏感性。结果表明： 1）SST异常首先引起大气环流的改变。 赤道东太平洋对流层下沉增强，而作为经向补偿，副热带东太平洋上升运动增强，其中南半球尤为明显，同时南半球热带中、西太平洋上升运动增强，加剧了该区纬向逆时针环流，说明冰期热带海气耦合过程受气候背景场（如SST）影响很大； 2）大气环流格局改变引起热带中西太平洋的大气加热、对流活动、表层风场及降雨的巨大变化。 140°E以西的婆罗洲和菲律宾区域，总的大气加热减少是由于对流与辐射加热减少所致，对应于该区风场辐散和降雨减少； 而140°E以东的南半球热带中、西太平洋，大气吸收热量增加，对流与辐射加热均增强，总降雨量也随之增加，反映该区赤道辐合带南移并增强。该项研究为探索热带太平洋在冰期/间冰期旋回中的古海洋学变化提供了新的数据支撑。此外，不同重建SST对赤道辐合带的影响比较大，因此利用重建SST进行数值模拟或者利用耦合模式研究LGM热带海气相互作用时，应该十分重视全球热带SST分布特征。 |
| 关 键 词： | 末次盛冰期 热带辐合带 暖池外海表温度 热带太平洋 古气候模拟 |
SENSITIVITY OF EQUATORIAL PACIFIC CONVERGENCE ZONE TO REVISED TROPICAL SEA SURFACE TEMPERATURE OUTSIDE THE WARM POOL DURING THE LAST GLACIAL MAXIMUM |
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| Wang Yue,Jian Zhimin,Zhao Ping.SENSITIVITY OF EQUATORIAL PACIFIC CONVERGENCE ZONE TO REVISED TROPICAL SEA SURFACE TEMPERATURE OUTSIDE THE WARM POOL DURING THE LAST GLACIAL MAXIMUM[J].Quaternary Sciences,2009,29(2):221-231. | |
| Authors: | Wang Yue Jian Zhimin Zhao Ping |
| Institution: | State Key Laboratory of Marine Geology|Tongji University|Shanghai200092; Chinese Academy of Meteorological Sciences|China Meteorological Administration, Beijing100081 |
| Abstract: | The Winter Eastern Equatorial Pacific(EEP)is one of the hotspots for the modern climate research because the magnitude of El Nio/La Nia is always intensified in the tropical Eastern Pacific during boreal winter. Paleoclimatic studies have also demonstrated that different patterns of tropical sea surface temperature(SST)could cause the changes of atmospheric circulation through tropical convections and atmospheric teleconnections，especially in the boreal winter of the Last Glacial Maximum(LGM). However，there are still large uncertainties in the reconstruction of LGM tropical SST，an important boundary condition for the paleo￣climate modeling. Based on the LGM SST reconstruction of the Climate，Long Rang Investigation，Mapping and Prediction(CLIMAP)project，the revised SSTs of the tropical Atlantic and EEP were reconstructed by Allan Mix of the Oregon State University(OSU). OSUs annual SST of EEP is 3～4℃ cooler than CLIMAP value，roughly similar to a perpetual La Nina climate state in this region. This OSU reconstruction is supported by recent studies on paleo￣ceanographic proxies such as 〖JB(〗Mg/Ca derived and U37K SST in the EEP. We used the OSU and CLIMAP SST reconstructions as boundary conditions of CAM30 to simulate how the variations of tropical SST outside the warm pool influence the tropical western middle Pacific convection and atmospheric circulations in the LGM boreal winter. Our main results include： (1)The atmospheric circulations are changed by the SST anomalies outside the warm pool： there is an anomalous descent in EEP as a response to the significant SST cooling of this region，while the ascent is enhanced in the subtropical Eastern Pacific as a meridional compensation，especially in the Southern Hemisphere. At the same time there is a strengthened tropical western middle Pacific ascent in the Southern Hemisphere which intensifies the zonal anticlockwise circulation. These changes indicate that the tropical atmospheric ocean coupled dynamics are strongly controlled by the climatic background fields such as SST during glacial periods.(2)The atmospheric heating，convection，surface wind and precipitation of tropical western middle Pacific are also largely changed by the atmospheric circulation anomalies： Philippine and Borneo west of 140°E are featured by decreased atmospheric heat，decreased convective heat and radiation，corresponding to the divergent wind and reduced precipitation. In the tropical western and middle Pacific of the Southern Hemisphere east of 140°E，there are increased atmospheric heat，convective heat and radiation with the enhanced precipitation，reflecting the intensification and southward movement of equatorial Pacific convergence zone in this region. This simulation provide new numerical data for the research of paleo￣ceanographic changes of tropical Pacific during the glacial/interglacial cycles. As only the revised SSTs of EEP and tropical Atlantic are considered in this study，the influence of tropical SST on the atmospheric ocean coupled dynamics must be further assessed with the SST reconstructions of all the tropical regions including the western equatorial Pacific. |
| Keywords: | Last Glacial Maximum Intertropical Convergence Zone sea surface temperature outside the warm pool tropical Pacific paleo￣climate modeling |
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