1991年江淮早梅及其与过赤道气流异常的关系

EARLY MEI-YU OVER THE JIANG-HUAI AREA IN 1991 AND ITS RELATION WITH THE ABNORMALITY OF THE CROSS EQUATORIAL CURRENT

关键词:  江淮梅雨  副高北跳  夏季风  过赤道气流异常

Key words:  Jiang-huai mei-yu  Northward-jumping of the subtropical ridge Summer monsoon  Abnormal cross equatorial current

摘要:

讨论了1991年江淮早梅现象及其形成机制。结果表明:5月第4候西太平洋副热带高压脊线出现第一次北跳,夏季风影响到江南,江淮地区入梅,比常年早二十多天;这与120—130°E间异常地出现较强的过赤道气流有关。

Abstract:

In this paper, the phenomenon of early Mei-yu over the Jiang-huai area in 1991 and its formation mechanism have been studied. The results indicate that in the fourth pentad in May, the first northward-jumping of the west Pacific subtropical ridge occurred, and the area south of the Yangtze river valley started to be influenced by the summer monsoon. and the onset of the Mei-yu period over the Jiang-huai area was more than twenty days earlier than that of the normal years; these are related to the relatively strong cross equatorial air current which appeared abnormally between 120°E and 130°E from the second pentad to the fifth pentad in May.