CAJ | 학술논문

通过诊断分析研究了北半球中高纬大气低频振荡随纬度的变化特征,利用1950-2005年北半球20～75°N逐日500 hPa位势高度场资料分析了功率谱.结果表明,(1)大气低频周期随纬度变化,夏季低频周期在45°N有最大值,为52.6 d,在低纬和高纬低频周期较小;冬季低频周期最大值位于35°N,为49.9 d,最小值位于60°N.(2)无论El Nino年还是La Nina年,低频周期随纬度变化幅度在夏季都较正常年剧烈,最大振幅达到30 d,而对冬季影响不大.原本位于35°N的最长低频周期在La Nina年移至65°N.(3)El Nino年和La Nina年,低频周期随纬度平均值在冬、夏季差异不大;而在正常年份和所有年份,低频周期随纬度平均值在冬、夏季差异明显.(4)就北半球平均而言,无论El Nino年、La Nina年、正常年还是所有年,夏季低频周期都要小于冬季;El Nino(La Nina)事件在冬、夏季都有使大气低频周期缩短(延长)的趋势.
통과진단분석연구료북반구중고위대기저빈진탕수위도적변화특정,이용1950-2005년북반구20～75°N축일500 hPa위세고도장자료분석료공솔보.결과표명,(1)대기저빈주기수위도변화,하계저빈주기재45°N유최대치,위52.6 d,재저위화고위저빈주기교소;동계저빈주기최대치위우35°N,위49.9 d,최소치위우60°N.(2)무론El Nino년환시La Nina년,저빈주기수위도변화폭도재하계도교정상년극렬,최대진폭체도30 d,이대동계영향불대.원본위우35°N적최장저빈주기재La Nina년이지65°N.(3)El Nino년화La Nina년,저빈주기수위도평균치재동、하계차이불대;이재정상년빈화소유년빈,저빈주기수위도평균치재동、하계차이명현.(4)취북반구평균이언,무론El Nino년、La Nina년、정상년환시소유년,하계저빈주기도요소우동계;El Nino(La Nina)사건재동、하계도유사대기저빈주기축단(연장)적추세.
A diagnostic analysis is carried out to investigate the intra-seasonal oscillations(ISO) in ex-tra-tropical latitudes. The power spectrum analysis is performed for the daily northern 500 hPa geopo-tential height field data in the mid-high latitudes(20-75°N) from 1950 to 2005. The conclusion is re-ceived that: (1) the cycle of ISO varies with latitudes. In summer, the longest cycle of ISO locates at 45°N,with a period of 52.6 d. However, the cycle of ISO tends to be small in relatively lower and higher latitudes. In winter, the longest cycle of ISO appears around 35°N, with a period of 49.9 d, while the shortest cycle of ISO lies around 60°N. During La Nina years, the location of longest cycle shifts from 35°N to 65°N. (2)The period of ISO varies with latitudes more greatly during ENSO-years, es-pecially in summer. (3)The difference of the ISO period between summer and winter during ENSO-years is tiny, but is great during normal-years and for all-years. (4)Main periods of ISO show a short-ening/lengthening tendency during El Nino/La Nina event.