北大西洋涛动/北极涛动与中国冷事件频数年际和年代际变化的联系及其差异  

Relationship between NAO/AO and Interannual and Interdecadal Variations of Cold Wave Frequency(CWF)in China

作　　者：张梦 陶丽[1,2] 邵海燕[1] ZHANG Meng;TAO Li;SHAO Haiyan(School of Atmospheric Sciences,Nanjing University of Information Science and Technology,Nanjing,210044,Jiangsu,China;Key Laboratory of Meteorological Disaster,Ministry of Education(KLME),Nanjing University of Information Science and Technology,Nanjing 210044,Jiangsu,China)

机构地区：[1]南京信息工程大学大气科学学院,江苏南京210044 [2]南京信息工程大学气象灾害教育部重点实验室,江苏南京210044

出　　处：《高原气象》2022年第4期850-863,共14页Plateau Meteorology

基　　金：国家重点研发计划项目(2016YFA0600402)。

摘　　要：利用1961-2017年中国457个站点的逐日气温观测资料、NCEP再分析资料及CRU陆地逐月气温资料对冬季(11月至次年3月)中国区域内发生的冷事件频数(cold wave frequency,CWF)年际和年代际变化进行分析。分析结果表明,虽然北大西洋涛动/北极涛动(NAO/AO)与中国CWF整体都具有显著的负相关关系,但这种负相关关系只与NAO/AO负位相年有关,在NAO/AO负异常年,CWF异常偏多,而CWF异常偏少年,并不对应NAO/AO正异常年,说明NAO/AO对中国冷事件频数影响是不对称的,且CWF异常偏少时,NAO指数正异常较AO更偏小,因此相对于AO与CWF的年际相关关系而言,NAO与CWF之间呈现出较弱的相关关系,也说明NAO对中国CWF影响更加不对称,中国区域CWF偏少可能由其他因子主导。环流场分析也证实了这种不对称性。此外,在全球变暖的背景下CWF并无明显增加或减少的趋势,但1961-1980年和2000-2017年期间CWF年际变化幅度较大,1980-2000年期间CWF年际变化幅度较小,CWF这种年际变幅的年代际变化与NAO的年代际变化有很好的相关关系,这可能是由NAO对中国冷事件频数影响的不对称性造成的。Based on the daily surface air temperature(SAT)data from 457 gauge stations of China,the monthly mean land SAT from Climatic Research Unit(CRU),the monthly reanalysis datasets from National Centers for Environmental Prediction(NCEP)during 1961-2017,we have investigated the interannual and interdecadal variation of cold wave frequency(CWF)during the 57 winters(November-March)in China.A cold-wave event was defined as at least one day of day-to-day drop of SAT and the other days of SAT anomaly should exceed 1σ(σis the standard deviation of SAT)in three consecutive days.The results showed that winter-averaged NAO/AO index was closely correlated with winter-&area-averaged CWF in China,with the correlation coefficient as high as-0.50 for AO index,and-0.31 for NAO index,which was consistent with previous studies.However,this negative correlation was highly contributed by the negative NAO/AO phases.CWF increased a lot in the abnormally negative NAO/AO years,but the significant reduction of CWF didn’t occur in the abnormally positive NAO/AO years.It implied that the influence of NAO/AO on CWF was asymmetric.Moreover,the positive anomalies of NAO index were smaller than those of AO index when CWF significantly reduced,so the correlation between winter-averaged NAO index and the CWF was weaker than that between winter-averaged AO index and the CWF,or the reduction of CWF might be dominated by other factors.In one word,NAO showed a more asymmetric influence on the CWF in China than AO.The circulation analysis also confirmed this asymmetry,there were no significant anomalies of SAT,SLP,and geopotential height in China in the abnormally positive NAO years.In addition,the trend of CWF was not observed under the background of global warming,but the variance of interannual variation of CWF was larger during 1961-1980 and 2000-2017 than that during 1980-2000.Further study suggested that the interdecadal change of the CWF variance was highly related to the interdecadal variation of NAO,with correlation coefficient between the v

关 键 词：冷事件频数 年际变幅 NAO/AO 影响的不对称性 

分 类 号：P466[天文地球—大气科学及气象学]