低纬高原罕见“雷打雪”中尺度特征分析  

Analysis on Mesoscale Characteristic of Rare Thunderstorm Snow Weather in Low Latitude Plateau

作　　者：郭荣芬[1,2] 鲁亚斌[2] 高安生[3] 李磊[1,2] 

机构地区：[1]云南大学大气科学系,昆明650091 [2]云南省气象台 [3]云南省气象局科技减灾处

出　　处：《气象》2009年第2期49-56,I0002,共9页Meteorological Monthly

基　　金：中国气象局2008年业务建设项目-灾害天气短时临近预报业务系统建设子项目"冰雹天气诊断识别研究"(编号2012209)资助

摘　　要：应用常规高空资料、FY-2C卫星红外和水汽图像、加密自动站地面观测资料,结合新一代多普勒雷达探测资料,综合分析了2008年2月28日夜间至29日凌晨发生在云南的“雷打雪”罕见天气现象。结果表明：南支槽和冷空气、西南低空急流的共同影响,是其发生的有利天气背景,其中强对流天气就发生在急流与锋面相互作用的湿度锋湿区内斜压不稳定的环境中。中-γ尺度对流云团生成并逐渐增强为中-β尺度对流云团是形成此次复杂对流天气的直接中尺度系统。多普勒雷达回波中,PPI上有回波强度达25-33dBz的“人字形”回波、钩状回波以及阵风锋的出现,相应VP-PI上出现逆风区、低层零线“S”形暖平流及“牛眼”结构是“雷打雪”天气中降雨转为冰雹、阵雪过程中,中尺度对流系统由弱变强的典型特征。地面逐时温、压、湿、风的迅速演变特征表现为雷暴发生前增温增湿和增压,温度、气压出现峰值,且气压曲线显示为圆顶状的中尺度雷暴高压特征;风的变化则表现为风向呈逆时针旋转,偏北风增大并出现风速峰值。雷暴过境时,要素显示为降温增湿,出现露点锋。Conventional observing data,FY-2C satellite infrared and vapor pictures,auto-station intensive surface observing data and new generation Doppler radar detection data were used to analyze an unusual ＂thunderstorm snow＂ weather event which happened from February 28 night to February 29 morning in 2008.The result indicated that the interaction of southern trough,cold air and south-west lower jet was the beneficial synoptic background.The strong convection weather just happened in the baroclinic instability environment of humidity front with the interaction between jet and cold front.The meso-γ-scale convective cloud grew and gradually strengthened to meso-β-scale convective cloud which was the primary meso-scale synoptic system and triggered this complex convective weather event.From the Doppler radar echo picture we could see that the band echo with the shape of ＂人＂ and ＂hail spike＂ hook echo with the echo intensity of 25～33dBz,and gust front can also be detected from the PPI screen.And from the VPPI screen,anti-wind area,lower level＇s zero isotherm ＂S＂ warm advection and ＂bull′s eye＂ structure can also be detected,which were classical features of meso-scale convective system′s changing from weakness to strength during the period of rainfall evolving to hail and snow in the ＂thunderstorm snow＂ weather.The fast evolving characters of hourly surface temperature,pressure,relative humidity and wind showed the value of temperature,pressure and humidity increased before the thunderstorm happened,and the value of temperature and pressure got to maximum,and the pressure curve appeared to dome-shaped meso-scale thunderstorm high pressure feature.And any other else,the evolving of wind showed the wind rotated anti-clockwise,and the northern wind velocity increased and the peak value appeared.When the thunderstorm passed,the meteorological factors showed the temperature decrensing,and the humidity increasing,and the dew point temperature got to peak value.

关 键 词：“雷打雪” 西南急流 中尺度系统 多普勒雷达特征 自动站要素 中尺度特征 

分 类 号：P458.121.1[天文地球—大气科学及气象学] P427.42