2011年3月12～14日河西走廊东部区域性寒潮天气分析

[目的]对2011年河西走廊一次寒潮天气过程进行分析,并总结预报经验。[方法]利用常规观测资料和Ecmwf数值产品资料,对2011年3月12～14日河西走廊寒潮天气过程发生的环流背景、成因及影响系统进行分析。[结果]此次寒潮出现在北半球中高纬环流形势由纬向型向经向型转换过程中;前期基础温度偏高是形成这次寒潮天气的前提条件;地面冷高强烈发展是形成寒潮天气的直接原因;强盛的冷平流是造成气温大幅下降的主要原因;雪后晴空辐射对局地气温也有一定作用。冷空气主力偏北、冷空气以扩散的方式东移南下、锋面过境时间偏早和高低层都辐合不利于深层对流发展以及高低空风速不大等都是影响大风偏弱的因素。[结论]该研究为进一步提高寒潮、大风天气预报水平提供了重要参考。

Study on Regional Cold Wave Weather in Hexi Corridor from March 12 to 14 in 2011

[Objective]The aim was to study the cold wave in Hexi Corridor in 2011 and summarize report experience.[Method]Routine observation data and Ecmwf numerical product were used to analyze the circulation background,causes and influential system of Hexi Corridor from March 12 to 14 in 2011.[Result]The cold wave in the mid-high latitude circulation in Northern hemisphere transited from radial type to warp type.High early basic temperature was the premise of cold wave.Drastic ground movement was the direct cause of cold wave.Prevailing cold advection was one primary cause of temperature reduction.Radiation in sunny days also posed certain influences on regional temperature.Factors weakened the gale were as follow,cold air largely in north area,cold air moving southeastward in diffusion,front passing early,upper and lower air convergence against the convection development and slow wind in high and lower air.[Conclusion]The study provided important references for further enhancement of cold wave and gale report.