【摘要】 利用美国国家环境预报中心(NCEP)的再分析资料,针对黑龙江省2009年春季和冬季3次暴雪过程,分析了螺旋度的分布与暴雪落区的关系。分析发现垂直方向上螺旋度的空间分布特征与低空系统有较好的对应关系,其强度变化既能反映天气系统的演变,又能对应大的降雪区域的变化。这样,垂直螺旋度的空间分布特征可用于确定影响系统的位置和降雪落区,垂直方向上螺旋度的强度与降雪的强度呈正相关。更多还原

【Abstract】 By using the NCEP reanalysis data,the relationship between the distribution of helicity and the falling regions of the heavy snow were analyzed for three snowstorms in spring and winter in 2009,Heilongjiang Province.The results showed the spatial distribution of vertical helicity correlated well with low layer system.The intensity change of vertical helicity not only reflected the development of synoptic system,but also the snowfall area.So,the spatial distribution of vertical helicity could be employed to confirm the position of system and snowfall regions.The intensity of vertica1 helicity was positively correlated with snowfall intensity.更多还原