夏季西北太平洋热带对流层上部冷涡的分析

SOME SYNOPTIC ASPECTS OF COLD VORTEXES OF TROPICAL UPPER TROPOSPHERE OVER NORTHWEST PACIFIC IN SUMMER

中文摘要:

      本文提供了夏季西北太平洋上空热带对流层上部冷涡出现的频率和典型云型。冷涡云型的特征是:冷涡中心附近是少云区,外部是大范围云带。对冷涡结构的分析表明:冷涡中心附近的少云区,在对流层里是干和冷的,它对应着天气尺度的下沉运动。冷涡外围的多云带是一条湿舌,从对流层下部向上直伸到400—300毫巴,并对应着天气尺度的上升运动。冷涡的特定结构,为台风初期发展,提供了一种可能的有利背景条件:1.在其外部云带里提供了穿过对流层中部的高θ_se通道。这条通道有利于维持强烈的上升运动,有利于扰动的存在。2.在其中心附近的少云区里,提供了补偿的下沉运动。这也是扰动能够存在所必需的。

英文摘要:

      The frequencies and cloud patterns of cold vortexes of tropical upper tropos-phere are studied. Near the center of typical cold vortex, there is a cloud less area with a surrounding cloud band. The inner cloud less area is dry and cool with subsiding motion in troposphere and the outer cloud band is wet with ascending motion extending from lower troposphere to 300-400 mb. The cold vortex may provide a favourable environment for initial development of typhoon. The outer cloud band provides a high-θse air path through middle troposphere, while the inner cloud-free area has compensative subsiding motion.