基于复杂网络的北半球遥相关年代际变化特征研究

Analysis of decadal characteristics of leading teleconnections based on complex networks theory

基于北半球中高纬度环流系统关联网络,研究了冬季北半球各种遥相关年代际尺度的变化特征及其与气候突变的可能联系等.研究结果表明,NAO,EUPA和WP等遥相关的作用中心在1970年代中后期和1990年代初期均对应有显著的跃变过程,且主要空间模态也发生一定的变化.结合网络顶点度,定义直接体现遥相关作用强弱的指数并分析其随时间的变化:1980年代以前以PNA,EUPA和WP三种模态的共同作用为主导,1980年代以后NAO的作用显著增强,1987年以后AO的作用显著增强,其他模态的作用则相对较弱.因此,多种遥相关年代际尺度的调整可能是1970年代中后期和1990年代初期气候突变的重要表现形式之一.

We construct a complex network of the middle latitude circulation system of north hemisphere（NCNH）.The decadal characteristic of leading teleconnection and its probable correlation with abrupt climate change are analyzed base on the circulation system network. Results show that（1） action centres of NAO,EUPA and WP have all moved during different periods in the recent 40 years and there has been a common abrupt change process as the end of the 1970s and beginning of the 1990s separately;（2） the new index which denotes the importance of teleconnection is defined using the node degree of NCNH.The temporal change of new index shows that the leading modes were PNA,EUPA and WP before the 1980s;index of NAO notably increased and all the five teleconnections were comparatively robust after 1980s;the index of AO notably increased and other modes comparatively decreased after 1987.So,center and index changes of decadal leading teleconnections may be another important phenomenon of abrupt climate change.