CAJ | 학술논문

南极涛动是南半球大气环流的主要模态,在多种尺度上对南半球及北半球部分地区的气候系统产生重要影响.在对树轮、珊瑚、冰芯等多种代用资料进行挑选与主成分分析的基础上,重建了公元1500年以来南半球夏季(当年12月-次年2月)的南极涛动指数.重建序列的解释方差(r~2)、误差减少量(RE)平均值分别为59.9%、0.47,较高的r~2、RE表明重建具有了较高的可信度;而整体呈减少趋势的标准误差(SE)表明代用资料的增多可以减少重建序列的不确定性.重建结果与其它研究给出的南极涛动指数有着较好的一致性.重建序列的功率谱分析表明,过去500多年南极涛动年际变率突出的周期有2.4a、2.6a、6.3a,年代际变率突出的周期有24.1a、37.6a,均达到95%显著性水平.进一步的小波分析表明南极涛动在不同时间尺度上的变率及其周期有着随时间而演变的特征.
남겁도동시남반구대기배류적주요모태,재다충척도상대남반구급북반구부분지구적기후계통산생중요영향.재대수륜、산호、빙심등다충대용자료진행도선여주성분분석적기출상,중건료공원1500년이래남반구하계(당년12월-차년2월)적남겁도동지수.중건서렬적해석방차(r~2)、오차감소량(RE)평균치분별위59.9%、0.47,교고적r~2、RE표명중건구유료교고적가신도;이정체정감소추세적표준오차(SE)표명대용자료적증다가이감소중건서렬적불학정성.중건결과여기타연구급출적남겁도동지수유착교호적일치성.중건서렬적공솔보분석표명,과거500다년남겁도동년제변솔돌출적주기유2.4a、2.6a、6.3a,년대제변솔돌출적주기유24.1a、37.6a,균체도95%현저성수평.진일보적소파분석표명남겁도동재불동시간척도상적변솔급기주기유착수시간이연변적특정.
The Antarctic Oscillation (AAO) is the dominant mode of atmospheric circulation variability over the southern hemisphere.It could not only play important roles in climate changes over southern hemisphere,but also exert lots of influences in some regions in northern hemisphere.Due to the lack of widespread instrumental records during historical periods,the understanding of the natural variability of AAO is limited.The purpose of this paper is to reconstruct an austral summer Antarctic Oscillation index (DJF-AAO) focusing on interannual-decadal variability since 1500 AD based on multiple proxies,such as tree-rings,corals,and ice-cores.A Marshall-AAO index derived from 12-station sea level pressure records since 1957 are selected as observational series for calibration.There are 263 variables retained after a series of screening criteria for proxies,to refine the major signatures contained in the proxies by applying principal component analysis,and then a series of screening criteria implemented again for the time coefficient (PC) corresponding to each eigenvector.After that,by applying multivariate regression method the observational AAO-PC relations were calibrated and cross-validated based on the period of 1957-1989,then regressions were employed to compute the DJF-AAO index in 1500-1956.In verification procedure we checked the explained variance (r~2),reduction of error (RE),and the standard error (SE).The cross-validation was performed by applying a leave-one-out validation method.During the reconstruction period of 1500-1956,the mean of r~2,RE,and SE are 59.9%,0.47 and 0.67,respectively.These statistical data indicate that DJF-AAO reconstruction is relatively reasonable for the last 460 years approximately.The reconstruction is compared favorably with several existing shorter AAO indexes derived from station SLP records both on the interannual and decadal time scales.The leading periods of the DJF-AAO index are ～2.4,～2.6,～6.3,～24.1,～37.6 years during the last 500 years,which are all significant at the 95% level.