CAJ | 학술논문

基于1960-2011年中国冬季区域性极端低温事件库，分别选取20世纪60年代中、70年代中、90年代初、21世纪初以及2008-2011年5个典型的区域性极端低温事件频发时段，从大气内部环流和海温外部强迫两个方面对各频发期的气候异常特征进行了对比分析。总体而言，20世纪60年代冬季区域性极端低温事件的强度大、频次高，在一定程度上表现为年代际尺度的持续性特征，而20世纪70年代中、90年代初、21世纪初则以年际尺度的振荡为主。此外，2008年以来的频发期在大气内部环流和北太平洋海温外部强迫两个方面均呈与20世纪60年代中期较为相似的特征：即欧洲至南亚大范围区域的地表温度异常偏低，欧亚中纬度500 hPa高度场距平呈显著的北正南负模态，急流区南北梯度异常显著，北极涛动具有明显的指数负位相特征，北太平洋海温异常偏暖，太平洋年代际振荡为典型的冷位相等；同时，当前频发期与其他时段的差异较大，特别是与20世纪90年代初的气候特征差异尤为明显。因此，2008年以来区域性极端低温事件频发期所对应的海-气系统异常除了具有全球变暖背景下的一些新特征之外，也初步出现了一些年代际变化的异常信号。
기우1960-2011년중국동계구역성겁단저온사건고，분별선취20세기60년대중、70년대중、90년대초、21세기초이급2008-2011년5개전형적구역성겁단저온사건빈발시단，종대기내부배류화해온외부강박량개방면대각빈발기적기후이상특정진행료대비분석。총체이언，20세기60년대동계구역성겁단저온사건적강도대、빈차고，재일정정도상표현위년대제척도적지속성특정，이20세기70년대중、90년대초、21세기초칙이년제척도적진탕위주。차외，2008년이래적빈발기재대기내부배류화북태평양해온외부강박량개방면균정여20세기60년대중기교위상사적특정：즉구주지남아대범위구역적지표온도이상편저，구아중위도500 hPa고도장거평정현저적북정남부모태，급류구남북제도이상현저，북겁도동구유명현적지수부위상특정，북태평양해온이상편난，태평양년대제진탕위전형적랭위상등；동시，당전빈발기여기타시단적차이교대，특별시여20세기90년대초적기후특정차이우위명현。인차，2008년이래구역성겁단저온사건빈발기소대응적해-기계통이상제료구유전구변난배경하적일사신특정지외，야초보출현료일사년대제변화적이상신호。
The climatic characteristics of the typical low-temperature periods of frequent occurrence were compared and analyzed based on the database of the Regional Extreme Low Temperature Events (RELTEs)in winter of China from 1960 to 2011.5 typical low temperature periods of frequent occurrence (the middle of 1960s,the middle of 1970s,the beginning of 1990s,the beginning of 2000s and 2008-2011 )were selected in order to analyze their scale characters.In general,RELTEs in 1960s which are characterized by high intensity and frequency exhibit a persistent feature of decadal scale,while other three frequent periods (the middle of 1970s,the beginning of 1990s and the beginning of 2000s)mainly show the annual oscillation character-istics.Besides,the inner atmospheric circulation and sea surface temperature (SST)external forcing are also compared among these 5 different periods.The results indicate that the current period of frequent occurrence has a similar character to that of 1960s,i.e.the surface temperature is extremely lower than normal from Europe to South Asia,the anomalies of 500 hPa field in the mid-latitudinal Europe-Asia show a north-positive and south-negative pattern,the north and south gradient at the west wind jet area is quite obvious,the AO index has the obvious character of negative phase,and the PDO shows the typical cold phase character with SST of the North Pacific warmer than normal.These characters are obviously different from other periods especially from 1990s.So,in addition to some new features in the background of global warming,the frequent occurrences of RELTEs recently might have implied some anomalous signal with the characters of decadal variability.