利用常规观测资料和NCEP 1°×1°再分析资料，对2009年11月1011日华北中南部大范围暴雪过程进行了分析。结果表明：（1）这次大暴雪发生在500 hPa高空槽、700 hPa低涡切变线及河套锢囚锋共同配合的天气系统下。（2）暴雪区位于200 hPa极锋急流入口区的右后方和副热带急流出口区的左前方、700 hPa西南急流的左前方、925 hPa和850 hPa偏东急流的右前方。（3）不同高度的急流共同作用形成这次大范围的暴雪天气过程。低空急流是在高空急流的耦合下形成和发展的。容易耦合的区域是在高空急流入口区右侧或在高空急流出口区左侧，正涡度平流随高度增大的区域。（4）西南急流为暴雪区提供充足的水汽并在暴雪区形成高湿区，从而建立和维持了暴雪区上空的对流不稳定层结。（5）西南急流与偏北急流在暴雪区上空形成辐合，在暴雪区上空产生抬升作用。（6）高、低空急流耦合所形成的次级环流，增加了上升运动并触发不稳定能量的释放，增加了暴雪强度和持续时间。（7）925 hPa东风急流在暴雪区的边界层形成了干冷空气垫，有利于偏南暖湿气流的爬升，加强了动力抬升作用。
The wide snowstorm in the middle and south of north China on 10-11 November 2009 was analyzed using the NCEP reanalysis data and the general automatic meteorological observing stations data. The results indicate that: (1)The snowstorm occurred in the weather system of upper trough on 500 hPa, low vortex and shear line, and Hetao front occlusion on 700 hPa. (2)The snowstorm located in the right back of the entrance of polar front jet stream and the front left of the subtropical jet stream on 200 hPa, the front left of Southwest jet stream on 700 hPa, and the front right of the easterly jet stream on 925 hPa and 850 hPa. (3)The snowstorm was caused by the jet streams at different altitudes. The low-level jet was formed and developed under the coupling of upper-level jet. The easy-coupling area is where positive vorticity advection is increasing when the altitude increases, in the right of the entrance area of the upper-level jet or the left of the exit area of upper-level jet. (4)Southwest jet stream has provided adequate water vapor for the snowstorm and formed the high-humidity area, which made and maintained the convection instability layer in the snowstorm area. (5)Southwest jet stream and Northerly jet stream formed convergence zone over the snowstorm area, which set up the raising movement of the weather scale for the snowstorm. (6)The secondary circulation caused by the coupling of upper-level and low-level jet increased the raising movement, triggered the release of unstable energy, and increased the intensity and duration of the snowstorm. (7)Easterlies on 925 hPa formed dry and cold mattress in the boundary layer of the snowstorm area, which helped the southerly warm and humid air to climb and strengthen dynamic lifting effect.
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