三门峡市一次大雪天气环流特征以及数值产品解释应用

在分析了环流背景、影响系统以及欧洲数值产品的基础上,结合MICAPS资料和多普勒雷达的反射率因子、径向速度、风廓线产品,对2011年2月28日大雪过程进行分析,同时又对数值产品进一步解释应用.结果表明:阶梯槽的同位相叠加和低层辐合线的加强南压是此次过程的主要影响天气系统;从这次降雪过程的组合发射率因子产品上看,本次降雪过程回波分布均匀、连续、范围较大;基本速度产品显示高层辐散,低层辐合,有利于降雪的形成;风廓线产品显示"天南地北"的形势.这样的流场配置对降雪比较有利,加大了垂直切变,有利于上升运动的加强.欧洲数值预报产品对本次降雪过程有一定的指导作用,高度场有较好的对应关系,温度场偏差较大,对降水量级不好把握.

Circulation Features of a Snow Weather in Sanmenxia City and Application of Value Products

By using the general circulation background,influence system and European numerical products,combining MICAPS material and doppler radar reflectivity factor,radial velocity,wind contour line products,the heavy snow on February 28,2011 in Sanmenxia City is analyzed,while applications for further explanation of the product value were carried out. The result show that ladder trough overlying and level convergence line strengthen are the main influencing weather system. Doppler radar combination emission rates show that this snow echo distribution is uniform, continuous,and the range is very large. Basic speed products show that the convergence at level and the divergence at upper is beneficial to the formation of the snow. The wind contour line products show that the flow field configura-tion of top south airflow and lower the north airflow,increased the vertical shear,which is helpful for the rising motion and strengthening. Europe numerical forecast products for this snowfall have some guidance. The height field has good correspondence;the temperature field has larger deviation;and the precipitation level is not easy to grasp.