【摘要】 运用天气学、卫星云图和物理诊断方法,分析20°N以北、130°E以西有台风活动,陕西有地面冷锋东移过境并出现大暴雨的3次典型天气过程,以揭示近海台风活动对青藏高原东北侧冷锋暴雨增幅的特征和规律。结果显示此类暴雨的中尺度对流云团位于冷锋云系的前部,其水平尺度在几十公里到300 km左右,生命史约6~8 h,中尺度系统常具有夜间发展、增强的特征。冷锋暴雨的水汽输送主要依靠台风低压外围的偏东急流来传递,水汽输送以850 hPa层附近最为显著。当台风西行移至台湾岛附近活动,而青藏高原东北侧的陕西有冷锋过境东移时,此时出现冷锋暴雨的降水增幅明显。更多还原

【Abstract】 The impacts of the characteristics and regularities of offshore Typhoons on cold-front heavy rainfall is revealed.Three typical cold-front heavy rainfall events in Shaanxi Province and the typhoon activities in north of 20°N and west of 130°E were studied by means of synoptic charts,satellite cloud pictures and physical diagnostic method.The results show that the mesoscale convective cloud cluster inducing this kind of heavy rainfall was located in the front of the cold-front cloud system with its horizontal scale being 10 km to 300 km and its life span being 6 to 8 hours.The mesoscale system developed and intensified mostly at night.The vapor for the cold-front heavy rainfall was transported by the easterly jet around the typhoon depression.The vapor transportation was mostly found at the 850 hPa level.The precipitation of the cold-front heavy rainfall increased while there was a typhoon moving westward to Taiwan Island and a cold front moving eastward to Shaanxi over the northeastern Tibetan.更多还原