CAJ | 학술논문

采用每日最高(最低)气温的历史同期序列的分位数作为该日的极端阈值,运用改进的经验模态分解(empirical mode decomposition,EMD)方法对山西省运城市1971-2005年每年发生的持续(3 d及3 d以上)极端气温频数进行了初步分析.结果表明,1971-2005年运城市每年的持续极端高温频数(frequency of sustained extreme-high temperature,FSEHT)和持续极端低温频数(fre-quency of sustained extreme-low temperature,FSELT)序列均存在线性下降趋势;在0.05的水平下, 运城市的FSEHT序列与该地区的年平均气温序列的线性相关性不显著,而该地区的FSELT序列与年平均气温序列的负线性相关关系是显著的;此外,这两个频数序列分别存在不同的周期振荡.从主要周期看,运城市的FSEHT和FSELT序列与厄尔尼诺现象的周期相一致.
채용매일최고(최저)기온적역사동기서렬적분위수작위해일적겁단역치,운용개진적경험모태분해(empirical mode decomposition,EMD)방법대산서성운성시1971-2005년매년발생적지속(3 d급3 d이상)겁단기온빈수진행료초보분석.결과표명,1971-2005년운성시매년적지속겁단고온빈수(frequency of sustained extreme-high temperature,FSEHT)화지속겁단저온빈수(fre-quency of sustained extreme-low temperature,FSELT)서렬균존재선성하강추세;재0.05적수평하, 운성시적FSEHT서렬여해지구적년평균기온서렬적선성상관성불현저,이해지구적FSELT서렬여년평균기온서렬적부선성상관관계시현저적;차외,저량개빈수서렬분별존재불동적주기진탕.종주요주기간,운성시적FSEHT화FSELT서렬여액이니낙현상적주기상일치.
In recent years, extreme weather events have caused the widespread concern of the Whole world,but sustained extreme temperature events have been seldom researched up to now.The extreme threshold of temperature is defined in this paper by the percentile value of time series of daily maximum or minimum temperature,and the annual frequency of sustained(greater than two successive days)ex-treme high(FSEHT)and low temperature(FSELT)events during 1971-2005 in Yuncheng are alia.1yzed with the improved Empirical Mode Decomposition(EMD)method presented by Deering.The re-suits show that during the 35 years,the FSEHT and FSELT series both exhibit a linear decreasing trend in Yuncheng;the negative linear correlation between the FSELT series and the annual mean temperature series is statistically significant at the 0.05 confidence level, while changes in FSEHT are almost not af-fected by the annual mean temperature. Besides there are also oscillations of different periods in the two frequency series;and in view of principle periods,the oscillations of the two series are consistent with those of El Nino events.