近500年南极涛动指数重建及其变率分析  

Antarctic Oscillation Index Reconstruction since 1500 AD and Its Variability

作　　者：张自银[1] 龚道溢[1] 何学兆[1] 雷杨娜[2] 冯胜辉[1] 

机构地区：[1]北京师范大学减灾与应急管理研究院,地表过程与资源生态国家重点实验室,北京100875 [2]陕西省气候中心,西安710014

出　　处：《地理学报》2010年第3期259-269,共11页Acta Geographica Sinica

基　　金：国家自然科学基金项目(40675035);公益性行业科研专项项目(GYHY200806010);国家科技支撑计划(2007BAC29B02)~~

摘　　要：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(r2)、误差减少量(RE)平均值分别为59.9%、0.47,较高的r2、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。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

关 键 词：南极涛动 重建 代用资料 年际-年代际变率 

分 类 号：P434[天文地球—大气科学及气象学]