石家庄春季大风变化特征及天气分型

Variation Characteristics of Gale in Spring and Its Weather Patterns in Shijiazhuang

利用石家庄地区17 个地面气象站近39 a（1972 ～2010 年）的常规观测大风资料,在分析石家庄地区春季（3 ～5 月）年平均大风日数空间分布特征的基础上,依据春季大风划分的局地、区域及大范围3 个等级,分别对其进行大风日数的月际、年际和年代际变化及周期、突变特征分析,最后根据天气形势对春季大范围大风的天气类型进行归纳总结.结果表明：1）石家庄地区春季年平均大风日数空间上呈“几”字形分布;2）春季3 个等级大风均以4 月份、1970 年代居多,且逐年呈显著线性减少趋势,而全区性的大范围大风发生频次少;3）3 个等级大风日数均明显的存在5 ～ 6 a 和14 a 的周期振荡,且在20 世纪80 年代发生了突变性减少;4）春季大范围大风为横槽型、冷空气偏东型、冷空气偏西型、冷空气偏北型4 种天气类型,且以横槽型和冷空气偏东型为主.

Based on the data of conventional wind days at 17 meteorological stations in Shijiazhuang from 1972 to 2010,the spatial distribution of gale days in spring（from March to May）were investigated. The gales in spring were first classified into three grades,including local gale,regional gale and wide range gale,according to the extent of gale occurrence region. Next,the further investigation onthe characteristics of variation in days of the three grade gales was carried out by using common statistical diagnosis methods. The results show that the annual mean days of gale in spring over Shijiazhuang spatially distributed in a “几”- shape with the whole - regionwide range gale days occurring at low frequency. Moreover,the days of three grade gales in spring reached their peaks in the 1970s andshowed a remarkable linear decreasing trend year by year. There was a substantial periodic oscillation in the temporal series of threegrade gale days while the gale days reduced abruptly in the 1980s. Based on the analysis