摘要
利用1979年1月到1987年12月美国国家气象中心六个层次的月平均风场资料,分析了东半球跨赤道气流的季节变化及其年际异常。得到冬、夏跨赤道气流的输送集中在对流层下部,冬季向南,夏季向北;春、秋跨赤道气流的输送集中在对流层上部,春季向北,秋季向南。低层跨赤道气流位置稳定,南北风方向转换时间为3月和11月;高层跨赤道气流位置变化较大,南北风转换时间为6月和1月。在El Nino年,跨赤道气流出现明显的异常,但表现形式不尽相同。ElNino年,夏季下层跨赤道气流稳定建立的时间比正常年推迟2—3候,且季内变化大,稳定维持时间短。
The seasonal variation of the cross-equatorial flow in the eastern hemisphereis analyzed by using the 6-level monthly mean wind data from January 1979 to Decem-ber 1987. The results are shown as follows:The center of the cross-equatorial flow ex-ists in the lower troposphere in winter and summer but in the upper troposphere inspring and fall. The flow propagates southward in winter and fall but northward in sum-mer and spring. The flow turns south wind into north wind in March and November inthe lower troposphere but in June and January in the upper troposphere. Remarkableanomaly is observed in the crossequatorial flow during the the El Nino year,but assumesdifferent forms. During the El Nino year, the summer lower cross-equatorial flow be-comes steadily set up 2-3 pentads later than during the normal year and has more in-traseasonal variation and shorter steay maintenance.
出处
《南京气象学院学报》
CSCD
1992年第2期37-44,共8页
Journal of Nanjing Institute of Meteorology
关键词
东半球
赤道
气流
季节变化
cross--equatorial flow
seasonal variation
El Nino
