中国冬季极端低温事件的多尺度特征  

Multi-Scale Variations of Winter Extreme Minimum Temperature in China

作　　者：黄菲[1] 胡蓓蓓[1,2] 周晓[1] 房永生 

机构地区：[1]中国海洋大学物理海洋实验室山东省高校海洋-大气相互作用与气候重点实验室,山东青岛266100 [2]南海舰队海洋水文气象中心,广东湛江524001

出　　处：《中国海洋大学学报（自然科学版）》2014年第10期42-50,共9页Periodical of Ocean University of China

基　　金：全球变化研究国家重大科学研究计划项目(2010CB951403;2012CB955604)资助

摘　　要：利用1961—2010年中国487站逐日气温资料,以35°N为界分北方区域和南方区域研究中国冬季极端低温事件的多尺度变化特征。研究表明:南、北方区域极端低温站点发生率呈现出准双周的气候季节内振荡,南、北方区域冬季极端低温频数和强度的长期变化一致,均呈减小趋势,频数和强度的趋势变化分别为-0.247d/10a(北方)、-0.352d/10a(南方)和-0.332℃/10a(北方)、-0.467℃/10a(南方),南方区域减小更迅速。北方区域极端低温频数和强度的年际和年代际变化信号强度相当,南方区域则以年际变化为主。进一步研究表明,当极端低温频数的线性趋势由正值变为负值,相应的大气环流由北极涛动负位相变为正位相。对年际变化分量(<8a),北方区域极端低温事件偏多时,海平面气压场表现为2波的定常波结构,西伯利亚高压和阿留申低压增强,对流层中层贝加尔湖槽加强;南方区域极端低温事件偏多时,海平面气压表现为偶极子型的1波结构,欧亚大陆和大西洋为正距平,北美大陆和太平洋为负距平,对流层中层东亚大槽加强南伸。对年代际变化分量(≥8a),大气环流形势都表现为北极涛动负位相,南方区域不显著。Based on the data set of daily minimum temperature in China during 1961—2010,multi-scale variations of winter extreme minimum temperature（EMT）over the north and south of China divided by35°N latitude line,are analyzed.Results show that the EMT frequency in the north and south of China both have quasi-biweekly climatological intraseasonal oscillation.In the north of China,the EMT frequency and intensity anomalies are decreased by 0.247d/10 aand 0.332℃/10 a,respectively.While The EMT frequency and intensity anomalies are decreased rapidly by 0.352d/10 aand 0.467℃/10 ain the south of China,respectively.For the north of China,the variance contribution between inter-annual（IA）and inter-decadal（ID）components of EMT frequency and intensity are almost equal.While for the south of China,the IA component variance contribution accounts for about two-thirds of total variance,and the ID component explains only about one-third of total variance.Further study shows that the Arctic oscillation changes from negative to positive phase when the frequencies of EMT changes from positive to negative linearly in the north and south of China.At inter-annual timescales（periods less than 8yr）,as the frequency of EMT in the north of China is more,characterized by Lake Baikal trough strengthened and enhanced Siberian High and Aleutian Low,associated with stationary wavenumber 2structures.As the frequency of EMT in the south of China is more,atmospheric circulation features a strengthened East Asian trough and positive anomalous sea level pressure over Eurasia and the Atlantic Ocean,while the North American continent and the Pacific showing negative anomaly,closely related to a wavenumber 1pattern.At inter-decadal timescales（periods longer than 8yr,the linear trend removed）,the increased EMT frequency in the north of China is associated with the negative phase of Arctic oscillation,but it is not significant in the south of China.

关 键 词：极端低温频数 多尺度变化特征 线性趋势 西伯利亚高压 东亚大槽 

分 类 号：P466[天文地球—大气科学及气象学]