利用烟台多普勒天气雷达探测资料和常规观测资料,对2005年12月3-4日、2008年12月4-5日和2010年1月3-4日山东半岛3次冷流暴雪过程的海岸锋气流结构进行了分析。结果表明,海岸锋是西北气流和北东北气流相互作用的结果,但气流强度有明显差异:一是西北气流明显强于北东北气流(类型Ⅰ),降雪回波源地在渤海东部区域,东南方向移动过程中逐渐发展,回波带的右侧进入陆地后减弱,左侧在海岸锋的作用下沿海岸锋发展,形成"列车"效应,产生强降雪;二是西北气流明显弱于北东北气流(类型Ⅱ),降雪回波源地在渤海海峡中部区域,东南方向移动过程中逐渐发展,右侧在海岸锋的作用下沿海岸锋发展,形成带状回波,产生强降雪,而回波带的左侧减弱。东部海区气旋的存在,决定了海岸锋北东北气流和西北气流强度结构的差异性。
Using Yantai Doppler radar data and observational station data,the airflow structure of three oceaneffect snowstorms occurred in Shandong Peninsula on 3 — 4 December 2005,4 — 5 December 2008 and 3—4 January 2010 were analyzed.The results show that a distinct,low-level convergence zone(coastal front) formed along the coast as winds over the ocean became north-northeasterly while winds over land remained northwesterly.But the intensity of airflow was obviously different,one structure was that the value of northwest wind was obviously higher than the value of north-northeast wind(Type Ⅰ),another structure was that the value of northnortheast wind was obviously higher than the value of northwest wind(Type Ⅱ).For type Ⅰ,radar products show that the initial echo generated in east Bohai sea,strengthened moving to south-east direction,the right side of echo band weaken while the band reached the land,the left side of echo band developed along the coast as a result of coastal front convergence zone and formed a remarkable ' train effect'.For type Ⅱ,radar products show that the initial echo generated in the central part of Bohai strait,strengthened moving to south-east direction,the right side of echo band developed along the coast as a result of coastal front convergence zone,while the left side of echo band weaken gradually.The cyclone on the sea area to the east of Shandong Peninsula determined differences between the north-northeast airflow intensity and the northwest airflow intensity.