东北地区寒潮特征及与影响因子关系的年代际变化

Interdecadal Variation of Cold Wave Characteristics and Its Relationship with Influencing Factors in Northeast China

利用1961~2020年东北地区106站逐日最低气温资料,梳理了东北地区寒潮频次,探讨了东北地区寒潮频次的年代际变化特征,诊断了东北地区寒潮频次影响因子的年代际变化,分析了PDO不同位相对东北地区寒潮频次与其影响因子关系的调制作用。结果表明,东北地区寒潮频次分为寒潮频次偏多期、振荡减少期以及迅速减少期3个阶段。寒潮频次偏多期主要受NAO影响;振荡减少期主要影响因子有AO、西伯利亚高压、NAO和贝加尔湖关键区;迅速减少期受AO、西伯利亚高压和东亚大槽影响明显。寒潮频次偏多期PDO为冷位相,NAO以负位相为主,西伯利亚高压强度偏强,贝加尔湖附近冷空气活动频繁,东亚大槽强度偏强,东北地区寒潮频次偏多;振荡减少期PDO转为暖位相,AO以正位相为主,西伯利亚高压强度指数减弱,NAO指数升高,西伯利亚高压强度减弱,贝加尔湖附近位势高度正异常,冷空气势力减弱,东北地区寒潮频次减少;迅速减少期各影响因子振荡加剧,对东北地区寒潮频次的影响减弱。

Based on the daily minimum temperature of 106 stations in Northeast China from 1961 to 2020,cold wave frequency of Northeast China was obtained,and it’s interdecadal variation and it’s interdecadal relationship with impact factors were diagnosed.PDO modulated the interdecadal relationship between cold wave frequency of Northeast China and its impact factors.The results show that in Northeast China,cold waves have 3 phases in lately 60 years.They are frequent occurrence phase,oscillation reduction phase and rapid reduction phase.In frequent occurrence phase,NAO is the main impact factor.In oscillation reduction phase,AO,Siberian High,NAO and key area around Lake Baikal are the major factors.In rapid reduction phase,cold waves are impacted by AO,Siberian High and East Asian Trough in Northeast China.In frequent occurrence phase,PDO’s cold phase,NAO’s negative phase,Siberian High’s high index,East Asian Trough’s lower index cause cold wave’s activity.In oscillation reduction phase,PDO’s warm phase,AO’s positive phase,Siberian High’s low index,NAO’s positive phase and positive anomaly around Lake Baikal cause Northeast China’s cold wave’s decrease.In rapid reduction phase,the impact factors change frequently and impact on code wave decrease.