【摘要】 利用常规观测资料、数值预报产品和NCEP全球再分析网格资料(1°×1°),对2009年11月5—11日新疆一次入冬转折性天气过程进行天气总结和诊断分析。结果表明乌拉尔山脊和深厚的西西伯利亚超长波槽的稳定维持、发展,不断增强的北风带引导极地冷空气向南爆发是本次天气主要的大尺度环流特征。冷空气主要来自于极地和西西伯利亚大陆,水汽来自于西南方向上的中亚地区,冷暖空气在北疆北部快速集中为大降水提供了充足的水汽和辐合上升运动。暴雪天气区动力结构清晰,散度场遵循高层辐散、低层辐合的经典配置;暴雪区整层大气都为垂直速度上升区,有强烈的上升运动;高空急流耦合的次级环流和中低层的低空急流加强了暴雪区的上升运动,强降雪落区位于高空急流入口区的右侧和低空急流的北侧。更多还原

【Abstract】 Based on the routine observing data,numerical prediction product and NCEP reanalysis data(1° x 1°),this synthesize analysis focused on a turning winter weather process from November 5 to 11 2009 in Xinjiang.It turned out that the existance and development of the Ural mountain ridge and deep West Siberian super long-wavelength trough and the cold air mass outbreak southward resulted by increased north wind was the large scale circulation characteristics of the process.The cold air was mainly from polar and West Siberian continent,and the water vapor was mainly from middle Asia.Plentiful water vapor and convergent ascending movement lead to strong rainfall on account of rapid converge of the cold and warm air in Northern Xinjiang.In the severe snow area,the dynamic structure was clear and the divergence field was characterized by convergence in the low layer and divergence in the upper.The vertical movement was obvious in the severe snow area.The sub-circulation of the coupled high jet and the low jet in the mid-low layer strengthened the vertical movement.And the severe snow area was located at the right of theentrance of high jet and the north of the low jet.更多还原