最近15万年来东亚古气候变化对日射响应的瞬变模拟  

A transient simulation of East Asian paleoclimate changes in response to insolation forcing during the past 150 ka

作　　者：李新周[1] 刘晓东[1] 

机构地区：[1]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,西安710075

出　　处：《地球环境学报》2012年第2期801-809,共9页Journal of Earth Environment

基　　金：国家重点基础研究发展规划项目(2010CB833406);国家自然科学基金项目(41075067;40825008)

摘　　要：本文利用美国大气研究中心通用气候系统模式(CCSM3)和地球轨道强迫加速技术完成了过去150 ka的长期瞬变模拟试验,重点分析了东亚气候演化对地球轨道参数改变引起日射变化的区域响应特征。结果表明:1)亚洲夏季风增强与岁差引起的北半球日射增多同相位,具有明显的约20 ka岁差周期,冬季风则具有约40 ka的斜率周期;2)夏季降水对日射变化响应区域差异明显,中国华北、青藏高原夏季降水对北半球平均日射有正响应,而华南和西北地区则相反;3)多旋回合成分析显示,岁差参数低(北半球夏季日射高)时,亚洲大陆普遍增温,青藏高原增温相对更显著,而地轴倾角偏高时引起的陆地增温在高纬更明显。东亚降水分布特征主要受岁差强迫影响。岁差引起的北半球夏季日射增多会导致中国华北和青藏高原区域降水普遍加强,与7个岁差周期合成的岁差参数极小值相对应的华北和青藏高原夏季降水较现代增加约30%,地轴倾角高低对东亚夏季降水影响不明显。轨道尺度东亚夏季降水分布特征可能主要与日射改变引起的夏季风和西太平洋副热带高压系统变化有关。Using the Community Climate System Model （CCSM3） from National Center for Atmospheric Research and Earth＇s orbital acceleration techniques, we conducted a long-term transient simulation for the past 150 ka by changing the Earth＇s three orbital parameters （preccesion, obliquity, eccentricity）. Based on the long-term modeling, we analyzed the responese of East Asian paleoclimate change to insolation forcing during the past 150 ka. The mian results are as follows： （ 1 ） The Asian summer monsoon change is approximately in-phase with the minimal precession （maximal insolation in boreal summer）, showing a remarkable period of 20 ka. The winter monsoon change generally follows the obliquity changes and produces a cycle cff 40 ka. （2） There are marked regional differences in the variations of East-Asian summer precipitation in respon~ to Northern I-Iemispheric solar radiation induced by the precession. The summer precipitation is synchronized with the boreal insolation cycle in North China and Tibetan Plateau regions. The situation is opposite in South China or Northwest China. （3） Composite analyses indicate that the surface temperature in the Asian continent generally increase with the boreal summer insolation in precessional cycles, especitally in the Tibetan Plateau. The larger differences in surface temperature occur in higher latitudes, characteristics of summer rainfall in East Asia are in response to obliquity forcing. The distribution mainly controlled by the precession forcing. The summer precipitation corresponding to maximal insolation in boreal summer rises by about 30% over North China and Tibetan Plateau against as that of present day. The orbital-scale variations of East-Asian summer rainfall may be related to changes in the monsoon circulation and western Pacific subtropical high pressure system.

关 键 词：轨道驱动 东亚古季风 通用气候系统模式 瞬变模拟 

分 类 号：P467[天文地球—大气科学及气象学] P532