东亚夏季风气候变迁强迫机制初探  

PRELIMINARY EXPLORATION OF FORCING MECHANISMS OF SUMMER MONSOON CLIMATE CHANGE OVER EAST ASIA

作　　者：刘晓东[1] 李力[1] 

机构地区：[1]中国科学院地球环境研究所,西安710054

出　　处：《海洋地质与第四纪地质》2000年第3期83-90,共8页Marine Geology & Quaternary Geology

基　　金：中国科学院"九五"重大项目!( KZ95 1-A1-4 0 2 -0 7-0 3 );国家攀登项目!( 95 -预 -4 0 -0 6-0 6)

摘　　要：基于反映东亚夏季风气候变迁的洛川黄土磁化率记录及一系列古气候模拟结果 ,通过统计分析研究了地球轨道参数、全球冰量及大气 CO2 含量等强迫因子对东亚夏季风气候变迁的影响。结果表明 ,在 10 5 a时间尺度上东亚夏季风气候变化大约有一半是由全球冰量消长引起的 ,约有 1/ 4归于大气温室气体含量的改变 ,而直接受到地球轨道的线性驱动作用很小。但在 10 3～ 10 4a时间尺度上 ,冰期时东亚季风边缘地区夏季气温和降水变化的70 %～ 80 %是由冰期边界条件 (包括冰量和大气温室气体含量 )造成的 ,而冰后期轨道强迫可以解释季风边缘地区夏季气候变化的 6 0 %以上。On basis of the magnetic susceptibility records of loess and paleosols at Luochuan on the Chinese Loess Plateau which serves as a proxy index of East Asian summer monsoon climate change and a series of paleoclimate simulation results from two atmospheric circulation models,the influences of the principal climatic forcing factors such as earth orbital parameters,global ice volume and atmospheric CO 2 concentration on the summer monsoon climate change over East Asia are studied by means of statistical analyses. The analysis of multiple linear regressions between the magnetic susceptibility and the SPECMAP deep sea δ 18 O representing global ice volume,July insolation at 65°N related to earth orbital parameters and atmospheric CO 2 concentration from the Vostoc ice core during the last 200 000 years shows these three factors can explain 80% of total variance of summer monsoon climate change over East Asia,in which variance contributions of global ice volume,atmospheric CO 2 concentration and orbital forcing amount to 50%,20% and 5% of the total variance respectively.In other words,the half of summer monsoon climate change over East Asia on the time scale of 10 5 years is ascribed to lower boundary conditions mainly determined by glaciation variations. Air surface temperatures and precipitations in the marginal area of East Asian summer monsoon(85 110°E,35 45°N)from 14 numerical simulations with the NCAR CCM0 and CCM1 are used to explore the sensitivity of East Asian summer monsoon climate to variations in insolation and boundary conditions under the assumption that simulated total climatic changes are the sum of two parts induced by boundary conditions and orbital forcing.The results show that the contributions of boundary conditions to climatic

关 键 词：东亚夏季风 黄土磁化率 古气候 气候强迫机制 

分 类 号：P532[天文地球—古生物学与地层学]