摘要
如果大气底层有一条强的湿度梯度带（底层“湿度锋”）则在尺度相对大的高空扰动诱发下，“湿度锋”南界附近最利于发生第二类条件不稳定，即在这里出现ＣＩＳＫ增长率极大轴。发展的南北向尺度基本取决于“湿度锋区”宽度。由此可在“湿度锋”紧南侧发展起一条具有相当正压结构的切变线。文中分别讨论了Ｅｋｍａｎ－ＣＩＳＫ和Ｗａｖｅ－ＣＩＳＫ两种情况，均有类似的结果。这种与低层“湿度锋”耦合的ＣＩＳＫ可以解释长江流域梅雨末期暖切变型梅雨锋的发生过程。
When there is a zone of strong moisture gradient (the “moisture front”) in the lowest layer of the atmosphere, the conditional instability of secondary kind (CISK) is most likely to occur near the south boundary of it induced by the disturbance in upper layers on a relatively large scale. This means that the increase rate of CISK will show a maximum axis here. The south-north extent of the development is also basically determined by the width of the “moisture front”. Through this mechanism, a shear line with equivalent-barotropic structure develops up south of the “moisture front”. oth the Ekman-CISK and wave-CISK are discussed in this paper and two results are nearly the same. Such a low level “moisture front”-coupling mechanism can explain the genesis of the warm shear line-type Meiyu front in the last stage of the Yangtze River valley Meiyu season.
出处
《大气科学》
CSCD
北大核心
1997年第6期679-686,共8页
Chinese Journal of Atmospheric Sciences
关键词
梅雨锋
暖切变型
CISK
湿度锋
低层
耦合
conditional instability of secondary kind low level “moisture front” coupling eqiuvalent barotropic shear line
