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doi:  10.12013/qxyjzyj2016-027
2016年1月赣北地区两次暴雪天气过程对比分析

Comparison of Two Snowstorm Processes in the Northern Jiangxi in January 2016
摘要点击 418  全文点击 4693  投稿时间:2016-05-18  修订日期:2016-06-30
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基金:  江西省气象局面上科研项目“九江市空气质量监测预警预报技术研究”;江西省气象局预报员专项“台风‘苏迪罗’暴雨分布特征及成因分析”
中文关键词:  暴雪,水汽输送,温度层结,可降水量
英文关键词:  snowstorms  water vapor  transportation  temperature distribution  PWV
     
作者中文名作者英文名单位
徐洁玲Xu Jieling九江市气象局, 江西 九江 332005
杨超Yang Chao九江市气象局, 江西 九江 332005
引用:徐洁玲,杨超.2016,2016年1月赣北地区两次暴雪天气过程对比分析[J].气象与减灾研究,39(3):198-205
中文摘要:
      利用常规观测资料、NCEP再分析资料、GPS/MET水汽资料和天气雷达资料,对江西省2016年1月22日和31日两次暴雪过程的动力条件、水汽条件和温度垂直结构等进行了对比分析。结果表明: 1) 500 hPa短波槽、700 hPa和850 hPa的切变线和西南急流是强降雪直接影响系统。整层大气高湿近于饱和,中低层有逆温。暴雪产生在700—500 hPa槽前西南气流的前部,850 hPa东北风与东南风辐合的区域,近地面层都是东北风。2) 两次暴雪过程水汽输送条件、冷空气的强度以及南下的方式都有差异。前次暴雪过程中低层先有冷空气影响,而后中高层暖湿气流北上,中低层能量低,以稳定性降雪为主,持续时间长;后次暴雪过程中,先是中低层暖湿气流北上,而后强冷空气从低层楔入,中低层对流不稳定,对流发展,降雪强度大,持续时间短。3) 两次暴雪期间GPS/MET可降水量均在20 mm以上,降雪开始前和暴雪出现前GPS/MET可降水量都出现连续增长的峰值,对降雪预报有一定的指示性。另外,雷达速度图上零速度线的形态变化对降雪持续时间有很好的指示意义。
Abstract:
      Based on conventional observation data, NCEP reanalyzed data, ground based GPS/MET remote sensing observation data of water vapor and Doppler radar observations data, the water vapor, thermal and dynamic conditions and the mesoscale characteristics of two snowstorms in Jiangxi province during 21-22 January and 31 January in 2016 were comparatively analyzed in this study. The results have shown that: 1) The two snowstorms were caused by the combined effects from the upper level trough at 500 hPa, the 700 hPa wind shear and 850 hPa southwest jet. It was characterized by the near saturated atmosphere at the whole level and temperature inversion at the middle low level. Besides, both two snowstorms occurred in the front of southwest airflow in the 700-500 hPa trough and the converged region of the northeastern and southeastern at 850 hPa. Northeast winds were prevailing on the surface layer. 2) There were different characters in the two snowstorms, including the water vapor transport conditions, the strength and southward moving track of cold surge. For the 22 January snowstorm, it was affected by the cold surge firstly, and then the warm and wet airflows run into middle high levels. Lower energy was stored in low levels, forming a stable heavy snow with longer duration. However, for the 31 January snowstorm, the warm and wet airflows inflowed firstly, then the cold air run into low levels, which resulted in the vortex in low levels and cyclone in the surface. Thus, it showed strong instability in middle low levels so that the convection developed, which led to a snowstorm with greater snowfall intensity but shorter duration. 3) The precipitable water vapor of GPS/MET was above 20 mm, and the amounts achieved positive extreme value before the two processes occurrences, which could be an useful precursor. Thus, the variations of shape of the zero line on the velocity field of Doppler radar could be a good indicator for the duration of the snowfall.
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