摘要
2005年11月18日凌晨至20日,哈密出现罕见暴雪天气过程,此次降雪强度大,范围集中,南部大,北部小。利用NCEP1°×1°的6小时分析资料和非常规观测资料,对此次哈密地区的暴雪天气过程的环流背景、影响天气系统进行了动力和热力的诊断分析,并利用Q矢量及螺旋度方法作了天气动力学诊断分析。结果表明:(1)新疆西部高压脊东移发展,引导萨彦岭低涡东移南压,移入哈密地区,造成哈密暴雪天气。(2)萨彦岭低涡是一较深厚系统,是低层辐合高层辐散的垂直上升气旋性涡柱,为暴雪发生提供了有利的动力机制。(3)冷暖平流交汇,增强了斜压性,有助于低涡的发展加强。冷平流对锋生起到重要作用。(4)Q矢量辐合区及螺旋度正值区与低涡有较好的对应关系,对哈密降雪的预报有一定的指示作用。
The weather process of the snowstorm happened in Hami Xinjiang during 18-20 November 2005 and the snow was heavier in the south than that in the north. Based on NCEP 1° × 1° 6h interval reanalyzed data and the non-conventional data, dynamic and thermodynamic diagnoses of the snowstorm caused by the vortex are discussed. And the methods of the Q vector and the helicity are also used to the further analysis. The results are as follows： （1） With the development and eastward movement of the ridge in the west of Xinjiang, the vortex in Sayangling moved into Hami area and caused the snowstorm. （2） This Sayanling vortex was a deeper and cyclonic system with upward motion. There was a convergence in the low levels and a divergence in the high levels. （3） The obvious temperature advection and temperature gradient can be revealed, so the baroclinicity was favorable to the intensification and development of the vortex. （4） The convergence area of the Q vector and the positive helicity area were consistent with the vortex, which can be used as an indicator in forecasting the snow in Hami.
出处
《气象》
CSCD
北大核心
2007年第6期67-74,共8页
Meteorological Monthly
基金
科技部"科研院所社会公益研究专项课题":不利气象条件对公路安全影响机理及对策研究项目(2004DIB3J100)
关键词
暴雪
诊断分析
Q矢量
螺旋度
snowstorm diagnostic analysis Q vector helicity
