【摘要】 本文通过对湘中、湘北地区42次强风暴资料的分析,建立了一个强风暴环境场的天气学模式,着重讨论了暖盖(即对流层中下层的逆温层)的形成和维持机理. 暖盖是由于绕过青藏高原两侧的两支西风波动相互作用而产生的.它的存在有利于低空急流在其东部边缘的低空加强,而低空急流引起的垂直环流反过来又有利于暖盖的维持,当暖盖下降到低空急流轴附近时因受扰动而破坏,引起强风暴的发生.更多还原

【Abstract】 In this paper, by analy/ing 42 severe convective storms in middle-north Hunan Province, a synoptic model of the environmental conditions of severe storms is developed. The great emphasis has been put on the mechanism for the formation and maintenance of the inversion layer prior to the outbreak of a severe storm.The inversion layer is formed by the interaction of two upper troughs moving eastward around the Qinghai-Xizang plateau. The inversion layer promotes the growth of the low-jet stream. On the other hand, the vertical circulation produced by the low-jet stream favors the maintenance of the inversion layer. When the inversion layer descends down to the height of the low-jet stream, it breaks down and a severe storm breaks out.更多还原