2011年贵州两次降雪天气过程的多普勒雷达产品特征分析
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摘要
利用常规观测和新一代多普勒天气雷达回波资料对2011年1月l7日至20日贵州省出现的两次降雪天气进行详细的特征分析。结果表明:贵州降雪回波强度一般<30 dBz,中心强度普遍在30～40 dBz之间,反射率因子的分布梯度不大;但降雪过程中夹杂冰粒的时候,回波中心强度能达到50 dBz。降雪回波的顶高一般在7 km以下,其中顶高5-7 km的情况占到60%左右,发展旺盛时回波顶高可达到8 km以上。降雪回波径向速度的等值线比较密集,沿径向梯度变化大。"牛眼"状回波是降雪回波的一个典型特征,"牛眼"状回波正负速度中心值的大小与降雪量存在一定的正比关系。风廓线产品的近地面层风向对于预报降水类型有明显的指示意义,当风廓线产品上近地面1.5 km高度的风向由东偏南转为东偏北时,地面冷平流取代暖平流,雨夹雪向纯雪转换,反之,暖平流取代冷平流,则是纯雪向雨夹雪转换,或者降雪减弱消失。
Using conventional observation and a new generation Doppler radar data on January 17 2011 to 20,analyzed the snowfall weather detailed features appeared twice in Guizhou.The results show that the snowfalls echoes generally are less than 30dbz,and center echoes intensity are between 30 to 40dbz,reflectivity factors distribution gradient is not big;but when the snowfall mingled with ice particles,center echoes intensity are 50dbz.The top highs of echoes of snowfall are under the 7km,and the top high of 5-7km accounted for about 60%,the most top high can be achieved 8km when the echoes are most vigorous.The radial velocity isolines of snow echoes are intensive,along the radial gradient changes are small."Bull 's-eye" shape echo is a typical features of snowfall echo,and it plus or minus speed central values with the amount of snow there exist certain proportional relations.Surface layer wind direction of wind profile product to forecast precipitation type has obvious indicator of significance.When the products of wind direction by the east south to north by east on the high of 1.5km,the ground cold advection replaced the warm advection,the rain and snow changed to pure snow,conversely,the warm advection replaced cold advection,and the pure snow changed to rain and snow or the snow weakened and disappeared.
Using conventional observation and a new generation Doppler radar data on January 17 2011 to 20,analyzed the snowfall weather detailed features appeared twice in Guizhou.The results show that the snowfalls echoes generally are less than 30dbz,and center echoes intensity are between 30 to 40dbz,reflectivity factors distribution gradient is not big;but when the snowfall mingled with ice particles,center echoes intensity are 50dbz.The top highs of echoes of snowfall are under the 7km,and the top high of 5-7km accounted for about 60%,the most top high can be achieved 8km when the echoes are most vigorous.The radial velocity isolines of snow echoes are intensive,along the radial gradient changes are small."Bull 's-eye" shape echo is a typical features of snowfall echo,and it plus or minus speed central values with the amount of snow there exist certain proportional relations.Surface layer wind direction of wind profile product to forecast precipitation type has obvious indicator of significance.When the products of wind direction by the east south to north by east on the high of 1.5km,the ground cold advection replaced the warm advection,the rain and snow changed to pure snow,conversely,the warm advection replaced cold advection,and the pure snow changed to rain and snow or the snow weakened and disappeared.
引文
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[11]姚立宏,方琼玉.2008年桂林降雪天气的雷达回波特征分析[J].安徽农业科学,2009,37(33):16440-16442.
[12]杨柳,苗春生,寿绍文,等.2003年春季江淮一次暴雪过程的模拟研究[J].南京气象学院学报,2006,29(3):379-384.
[13]林易.一次强降雪天气过程分析[J].贵州气象,2005,29(S1):52-53.
[14]汤俊,杜晓玲.EPV在贵州降雪天气预报中的应用[J].贵州气象,2002,26(6):14-15.
[15]张培昌,杜秉玉,戴铁丕.雷达气象学[M].北京:气象出版社,2001:331.
[2]池再香,胡跃文,白慧.“2003.1”黔东南暴雪天气过程的对称不稳定分析[J].高原气象,2005,24(5):792-797.
[3]姜红霞,范玉鑫,白燕.辽源地区一场特大暴雪天气过程形势分析[J].安徽农业科学,2009,37(27):13147-13149,13 210.
[4]董伟,王丽娜.一次东北暴雪天气过程诊断分析[J].安徽农业科学,2008,36(31):13774-13776.
[5]沐贤俊,况祥,王西贵,等.2008年1月安徽一次大范围暴雪天气诊断分析[J].安徽农业科学.2009,37(29):14269-14 271.
[6]宋丹,胡跃文,刘丽萍.贵州近44a降雪天气形势及物理量诊断分析[J].气象科学,2008,28(增刊):71-77
[7]刘宁微.“2003.3”辽宁暴雪及中尺度系统发展和演变.南京气象学院学报,2006,29(1):129-135.
[8]张勇,寿绍文,王咏青,等.山东半岛一次强降雪过程的中尺度特征[J].南京气象学院学报,2008,31(1):53-62.
[9]吴海英,曾明剑,蒋义芳,等.多普勒天气雷达资料在一次雨雪天气过程中的应用分析[J].气象科学,2007,27(2):208-213.
[10]东高红,张志茹,李胜山,等.一次大雪天气过程的多普勒雷达特征分析[J].气象,2007(7):75-81,130.
[11]姚立宏,方琼玉.2008年桂林降雪天气的雷达回波特征分析[J].安徽农业科学,2009,37(33):16440-16442.
[12]杨柳,苗春生,寿绍文,等.2003年春季江淮一次暴雪过程的模拟研究[J].南京气象学院学报,2006,29(3):379-384.
[13]林易.一次强降雪天气过程分析[J].贵州气象,2005,29(S1):52-53.
[14]汤俊,杜晓玲.EPV在贵州降雪天气预报中的应用[J].贵州气象,2002,26(6):14-15.
[15]张培昌,杜秉玉,戴铁丕.雷达气象学[M].北京:气象出版社,2001:331.