海洋影响下的山东半岛冷流降雪  

Sea effects on local snows at Shandong Peninsula

作　　者：于群[1,2] 周发琇[1] 王启[1] 

机构地区：[1]中国海洋大学海洋环境学院,山东青岛266100 [2]山东省气象局气象信息中心,山东济南250031

出　　处：《华东师范大学学报（自然科学版）》2009年第3期160-169,共10页Journal of East China Normal University(Natural Science)

基　　金：2008年河口海岸科学全国博士生学术论坛资助;国家自然科学基金(40675068);中国气象局新技术推广项目“灾害天气国家重点实验室开放课题”(CMATG2007Y08)

摘　　要：为探讨山东半岛北部冷流降雪的气候条件及其形成机理,采用经验正交函数(EOF)方法有效地分离出系统性降雪和局地降雪即冷流降雪.通过回归和合成分析揭示了冷流降雪多发时典型的环流特征是低层温度场落后高度场,强冷平流伴随冷槽加深,西北风加强.在此环流背景下,低层大气层结不稳定、充分的热量、水汽输送是局地降雪的主要气候原因.根据热力、水汽和层结等条件的分析表明,12月具备最佳降雪条件,与观测事实一致.沿海边界层的斜压结构、陆面摩擦与地形强迫,使上升运动加强,形成了半岛局地降雪特有的空间分布型.进一步分析表明,低频重力内波有可能成为激发对流,组织降雪的动力因子之一.Two kinds of snows, called systematic snow and cold outbreak snow, at northern Shan-dong Peninsula were identified by using EOF （empirical orthogonal function）. Forming mechanism of cold-outbreak snow, namely cold snow, discussed climatically. The favorable circulation pattern is low- level strong cold advection accompanied by deepening trough with N-NW flow strengthening. Then heat flux and water vapour from the sea, as well as low-level stratification instability play an important role. The results show that thermal regime and evaporation in December in a year provide more advan-taged capability for local snow, as accords with the observational facts. It is baroclinic boundary layer and land friction and orographic forcing that strengthen convection, so that peculiar spacial snow pattern forms at Shandong Peninsula. Further study shows that low-frequent inner gravity wave is one of important dynamical factors which are able to inspire convection and organize snow.

关 键 词：冷流降雪 海-气相互作用 海-陆相互作用 山东半岛 

分 类 号：P732[天文地球—海洋科学]