Astronomically modulated late Pliocene equatorial Pacific climate transition and Northern Hemisphere ice sheet expansion  

作　　者：MA WenTao TIAN Jun LI QianYu 

机构地区：[1]State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China

出　　处：《Chinese Science Bulletin》2010年第2期212-220,共9页

基　　金：supported by the National Natural Science Foundation of China (Grant No. 40776028 and 40621063);National Basic Research Program of China (Grant No. 2007CB 815902);the FANEDD (Grant No. 2005036),and Fok Ying Tong Education Founda-tion (Grant No. 111016)

摘　　要：The equatorial Pacific underwent a significant climate transition during the late Pliocene, which is characterized by cooling of global sea surface temperatures (SSTs) and formation of a marked SST gradient between the eastern and western equatorial Pacific. Moreover, this transition was nearly synchronous with the late Pliocene Northern Hemisphere glaciation. Probing the relationship among solar insolation, low and high latitude processes is the key to unravel the mechanism of this climate transition. A series of statistical methods were used in this study to analyze the orbital components of the equatorial Pacific SST and global ice volume records for the past 5 Ma. We found that integrated solar insolation rather than the monthly mean insolation is the primary external forcing of the late Pliocene climate transition, and that on orbital time scale the SSTs of the eastern and western equatorial Pacific display consistent change rather than a "seesaw" pattern. Changes of Earth’s orbital configuration have been responsible for this climate transition whereas the feedback effects of atmospheric CO2 concentration have further cooled the global climate since the early Cenozoic.The equatorial Pacific underwent a significant climate transition during the late Pliocene, which is characterized by cooling of global sea surface temperatures （SSTs） and formation of a marked SST gradient between the eastern and western equatorial Pacific. Moreover, this transition was nearly synchronous with the late Pliocene Northern Hemisphere glaciation. Probing the relationship among solar insolation, low and high latitude processes is the key to unravel the mechanism of this climate transition. A series of statistical methods were used in this study to analyze the orbital components of the equatorial Pacific SST and global ice volume records for the past 5 Ma. We found that integrated solar insolation rather than the monthly mean insolation is the primary external forcing of the late Pliocene climate transition, and that on orbital time scale the SSTs of the eastern and western equatorial Pacific display consistent change rather than a ＂seesaw＂ pattern. Changes of Earth＇s orbital configuration have been responsible for this climate transition whereas the feedback effects of atmospheric CO2 concentration have further cooled the global climate since the early Cenozoic.

关 键 词：赤道太平洋 全球气候 上新世 北半球 晚期 数字调制 冰盖 赤道西太平洋 

分 类 号：P467[天文地球—大气科学及气象学] X16[环境科学与工程—环境科学]