摘要
利用2002年中国南极考察期间在东南极冰盖Princess Elizabeth地区钻取的LGB69冰芯,对其海盐离子与大气环流的关系进行了分析.结果表明:冰芯主要化学离子的经验正交函数(EOF)分解的第一特征向量(EOF1)可以作为描述海盐气溶胶的传输强度的代用指标,可用于表征南印度洋准定常低压带海平面气压(SLP)的变化.冰芯最近23 a(1979-2001年)的记录与SLP和低层风场的相关模态反映了海平面气压场准半年振荡(SAO)和南极大陆边缘下降风的季节特征.LGB69冰芯很好地记录了1708-2001年间南半球环状模(SAM)的变化特征,Na+时间序列呈现的3.5 a周期变化与SAM的周期变化具有很好地一致性.在1970年SAM转为正位相后,其与Na+的相关关系也由负相关转为正相关.LGB69冰芯的海盐离子可以作为重建过去近300 a海平面气压场和SAM变化的代用指标.
A 293-year, annually-resolved ice core record from LGB69, Princess Elizabeth Land, East Antarctica,is used to investigate the atmospheric circulation variability over the mid-to high-latitude southern Indian Ocean（ SIO）. The first EOF（ EOF1） of chemical ions in the LGB69 ice core is indicative of changes in both mean sea level pressure and the low level wind fields over the SIO. Changes in sea-salt record（ also EOF1）are strongly correlated with the SIO low（ r =-0. 4,P〈0. 1） and the zonal westerlies（ r = 0. 5,P 〈0. 02）,with the highest correlation occurring in austral autumn（ March to May） probably due to the effects of the semiannual oscillation. Changes in EOF1 are also strongly correlated with meridional inland wind,with the highest correlation（ r =-0. 4,P〈0. 1） found during austral summer（ December to February） when katabatic winds prevail in coastal Antarctica. Further analysis indicates that the Na＋records were negatively correlated with the Southern Annular Mode（ SAM） during the period 1850 to 1970,but positively correlated during the period 1971 to 2001 in correspondence to the shifted SAMphase. Additionally,the 3. 5 years periodicity of the Na＋records,which occurred discontinuously from 1708 to 2001,shows good coherence with the periodicity of the SAMindex series.
出处
《冰川冻土》
CSCD
北大核心
2015年第2期286-296,共11页
Journal of Glaciology and Geocryology
基金
国家重点基础研究发展计划项目(2007CB411503)
国家自然科学基金项目(41121001)
中国极地科学战略研究基金项目(2012-14-02-02)资助
