1980～2014年中国中东部持续性霾天气的多尺度变化特征

An Analysis of the Multi-scale Variations of Persistent Haze Events in Central and Eastern China from 1980 to 2014

对1980~2014年中国中东部地区324个台站的持续性霾天气的时空变化和相关气象影响因子进行分析,结果表明:中东部地区年平均持续性霾事件和其在所有霾事件的贡献比例逐年增加,增长率分别为0.79(10 a)^-1和2.7%(10 a)^-1。主要表现为3个大值区:华北平原地区(包括山西省、京津冀地区)、长江三角洲和四川盆地东部,增加最显著的区域位于黄淮地区,增长率分别为6.3(10 a)^-1、13.95 d(10 a)^-1。1月是持续性霾事件的高发月,月均2.56 d。夏季和秋季持续性霾事件增加最为明显,增长率分别为0.38(10 a)^-1和0.46(10 a)^-1。不利的气象条件,如静风日数的增加,风速和大风日数的减少,以及不利的环流形势,如东亚冬季风的减弱,都可能造成持续性霾天气的增加和异常维持。

The spatial and temporal variations of persistent haze events and their related impact factors were analyzed by using 324 stations in the central and eastern China during 1980-2014.The results show that the annual average frequency of persistent haze events and their contributions to total haze events increase year by year,with growth rates of 0.79(10 a)^-1 and 2.7%(10 a)^-1,respectively.It is represented by three large-value areas:The North China Plain(including Shanxi Province,Beijing-Tianjin-Hebei region),the Yangtze River Delta,and the eastern Sichuan Basin.The most significant increase appears mainly in Huang-Huai area,with a growth rate of 6.3(10 a)^-1 and 13.95 d(10 a)^-1.At the same time,persistent haze events show obvious seasonal and monthly changes.January is the highest incidence month with 2.56 d,meanwhile high frequency appears in summer and autumn,with a growth rate of 0.38(10 a)^-1 and 0.46(10 a)^-1.Unfavorable meteorological conditions,such as increasing windless days,decreasing wind speed and gale days,and adverse circulation situations,such as the weakening of the East Asian winter monsoon,have resulted in an increase in persistent hazy days and its abnormal maintenance.