范俊红,易笑园. 2019. 大范围持续暴雪过程中多种影响系统的对比分析[J]. 气象学报, 77(6):965-979, doi:10.11676/qxxb2019.045
大范围持续暴雪过程中多种影响系统的对比分析
Comparative analysis of several influencing systems in the process of a large-scale continuous snowstorm
投稿时间:2018-07-30  修订日期:2019-02-25
DOI:10.11676/qxxb2019.045
中文关键词:  大范围持续暴雪  华北锢囚锋  江淮气旋  北路冷锋  特征对比
英文关键词:Large-scale continuous snowstorm  North China occluded front  Jianghuai cyclone  Northly cold front  Characteristic comparison
基金项目:河北省科技厅科技支撑计划项目(14275402D)、国家自然科学基金项目(41075030)。
作者单位E-mail
范俊红 河北省气象服务中心, 石家庄, 050021
河北省气象与生态环境重点实验室, 石家庄, 050021 
 
易笑园 天津市气象台, 天津, 300074 yixy123@sina.com 
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中文摘要:
      持续48 h的大范围雨转暴雪天气先后影响了陕西、山西、河北、北京、天津、辽宁等地,华北地区降雪量15—30 mm。此次过程中地面影响系统复杂,有华北锢囚锋、江淮气旋、北路冷锋。利用准地转理论、凝结函数法、垂直剖面分析和常规观测资料、GFS 0.5°×0.5°再分析资料等,对比分析了华北锢囚锋和江淮气旋在降雪量和降水效率、水汽和动力条件、垂直结构等方面的特征和差异,并描述了多种地面影响系统的演变和相互作用。结果表明:(1)在降雪量和效率上,华北锢囚锋降雪量小于江淮气旋,华北锢囚锋主要影响华北西部,降雪持续24 h,江淮气旋主要影响华北中东部,降雪持续30 h;降水前半段华北锢囚锋降水效率为0.76,江淮气旋为0.58,降水后半段两者均为1.5。(2)在水汽条件上,华北锢囚锋明显弱于江淮气旋,华北锢囚锋水汽通道在700 hPa上,来自西南地区,而江淮气旋在700和850 hPa上,来自西南地区和东海;华北锢囚锋水汽含量中心和水汽辐合中心主要集中在近地面层锢囚锋附近,而江淮气旋在800—600 hPa气旋北侧偏南气流里。(3)在动力条件上,华北锢囚锋明显弱于江淮气旋,华北锢囚锋南段涡度平流垂直微差项起主要作用,北段温度平流拉普拉斯项起主要作用,江淮气旋温度平流的拉普拉斯项和涡度平流的垂直微差项均起到重要作用。(4)在垂直结构上,江淮气旋锢囚时为冷式锢囚,并有北路冷锋楔入其暖锋下面,强度明显强于华北锢囚锋。(5)在演变和相互作用上,江淮气旋的北上减弱了华北锢囚锋;北路冷锋对随江淮气旋北上的暖湿气流起到“冷垫”抬升作用。
英文摘要:
      A large-scale rain and snowstorm lasted for 48 h and successively affected Shaanxi, Shanxi, Beijing, Hebei and Liaoning. The snowfall reached 15-30 mm in North China. Surface systems influencing the above rain-snowstorm process are complicated, including the North China occluded front, the Jianghuai cyclone and the northly cold front. By using the quasi-geostrophic theory, the condensation function analysis, vertical cross section analysis, conventional observation data and the GFS 0.5°×0.5° reanalysis data, characteristics and differences in water vapor content, dynamic condition and vertical structure, etc. between the North China occluded front and Jianghuai cyclone and their impacts on snowfall and snowfall efficiency are analyzed. Evolutions and interactions of various surface systems are described as well. The results show that:(1) Considering the snowfall and efficiency, the snowfall amount produced by the North China occluded front was less than that produced by the Jianghuai cyclone. The North China occluded front mainly influenced western North China, where the snow lasted for 24 h. The Jianghuai cyclone mainly affected central and eastern North China, where the snowfall lasted for 30 h. In the first half period of precipitation, the precipitation efficiency of the North China occluded front was 0.76,and that of the Jianghuai cyclone was 0.58; in the later half period, the precipitation efficiency was 1.5 for both systems. (2) Looking at the water vapor condition, the North China occluded front was obviously weaker than that of the Jianghuai cyclone. The water vapor supply for the North China occluded front came from the southwest and large transport occurred on 700 hPa; the water vapor supply for the Jianghuai cyclone came from the southwest and the East China Sea, and large transport were found on the levels of 700 and 850 hPa. The water vapor content and convergence center of the North China occluded front were mainly concentrated near the surface layer, while those of the Jianghuai cyclone were located in 800-600 hPa. (3) Considering the dynamic condition, the North China occluded front was obviously weaker than the Jianghuai cyclone. The vertical differential term was dominant in vorticity advection in the southern part of the North China occluded front, where as the Laplace term played a major role in temperature advection in the northern part. The vertical differential term for vorticity advection and the Laplace term for temperature advection both were important in the Jianghuai cyclone. (4) On the vertical structure, the Jianghuai cyclone was a cold occluded front with the northly cold front undercutting the warm front zone aloft, and its intensity was stronger than that of the North China occluded front. (5) On the evolution and interaction, the northward movement of the Jianghuai cyclone weakened the intensity of the North China occluded front, and the northly cold front behaved like a "cold pad", which uplifted the warm and moist air flow associated with the Jianghuai cyclone.
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