摘要
本文利用常规探空和地面观测资料、NCEP 1.0×1.0再分析资料及多普勒雷达资料,对2014年2月上中旬发生在湖南的三次雨雪过程(简称"14·02")进行了对比分析。结果表明:(1)第一次过程湘南出现冻雨,温度层结表现为850~700 hPa有明显逆温层,700 hPa温度高于0℃,850和925 hPa温度低于-4℃,地面温度低于0℃。从主要影响系统配置来看,700 hPa强盛的西南急流为水汽的输送和湘南融化层的形成和维持起到了重要作用,低层冷空气受南岭山脉阻挡而形成的地面静止锋和深厚的冷垫是导致湘南冻雨较长时间维持的原因。(2)第二、三次过程以降雪为主,温度层结显示地面温度0℃左右,地面以上层次温度低于0℃。(3)第三次雨雪强度最强,暖湿空气沿锋面强迫抬升,在低层冷空气共同作用下,导致较强雨雪天气的发生。雷达回波显示强降雪过程具有积层混合性降水回波及低质心高效降水回波特征。
Using conventional sounding data,surface observation data,NCEP 1 .0 ×1 .0 reanalysis data and Doppler radar data,three times of rain and snow processes in Hunan in early February 2014 are analyzed. The results show that (1 )the first process is a freezing rain process in southern Hunan,which is charac-terized by obvious inversion layer between 700 hPa and 850 hPa.The temperature at 700 hPa is above 0℃, but at 850 hPa and 925 hPa it is below -4℃ while the ground temperature is below 0℃.From the per-spective of main system configuration,strong southwest jet at 700 hPa plays an important role in water va-por transmission and the formation of melting layer.A stationary front and deep cold pad which is com-prised of the cold air blocked by Nanling Mountains,are the causes for the long lasting southern Hunan freezing rain.(2 )The second and third processes are snow-based processes with surface temperature around 0℃,and the temperature above surface is lower than 0℃.(3 )The third process of rain/snow is the heaviest.Warm moist air rises along the front,and low-level cold air results in this severe rain and snow process.Radar echo of this process has the characteristics of mixed echo of cumulus and stratus as well as low-centroid high efficient precipitation feature.
出处
《气象》
CSCD
北大核心
2014年第12期1500-1506,共7页
Meteorological Monthly
基金
公益性行业(气象)科研专项(GYHY 201306016)
中国气象局关键技术集成项目(CMAGJ2014M37)共同资助
关键词
降水相态
锋区强度
概念模型
过程对比
precipitation phase
frontal intensity
concept model
process contrast
