京津冀地区一次强沙尘天气过程的成因及特征分析
投稿时间:2018-04-28  修订日期:2018-07-14  点此下载全文
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作者单位E-mail
彭舒龄 中国人民解放军61206部队 pengshuling0216@163.com 
周树道 国防科技大学气象海洋学院南京信息工程大学 气象灾害预警与评估协同创新中心 zhousd70131@sina.com 
卫克晶 国防科技大学气象海洋学院南京信息工程大学 气象灾害预警与评估协同创新中心  
沈奥 中国人民解放军94303部队  
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目)
中文摘要:利用常规污染物监测资料、卫星资料和再分析资料等,对2017年春季京津冀地区遭遇的一次强沙尘天气过程进行分析。结果表明,此次过程是由地面冷锋过境,高空槽后冷空气持续补充引起,沙源地主要位于巴丹吉林、腾格里沙漠,随后以西北路输送至京津冀地区;前期沙源地感热通量迅速增大与中低层冷平流叠加,增强了不稳定层结,助于起沙;高空强风速带加强并向下延伸,中低层次级环流发展,不但使沙尘传输并下降至地面,而且使高层高动量和高位涡冷空气下传,促进低空急流形成、低层系统发展,使大风及沙尘天气维持;负值水平螺旋度与沙尘天气发生区有较好的对应性;沙尘过境时,地面至4km高度存在沙尘型气溶胶,PM2.5和PM10浓度变化较一致并达到重度污染水平,且AOD与AQI具有较好的时空匹配关系,重污染时段AOD值大于1,污染减弱时AOD值降至0.6以下。
中文关键词:沙尘  感热通量  高低空急流  动量下传  AOD
 
Causes and Characteristics of a Dust Weather Process in the Beijing-Tianjin-Hebei Region
Abstract:Based on the routine pollutant monitoring data, satellite data, reanalysis data and so on, a strong dust weather process in Beijing-Tianjin-Hebei region in 2017 was analyzed. The results showed that this process was mainly caused by cold fronts, with the continuous supplement of cold air after the trough. The sources were mainly located in the Badan Jilin desert and Tengger desert, and the dust was transported to the Beijing-Tian-Hebei region by northwest path. The sensible heat flux increased rapidly in the sand-dust sources, which combined with the cold advection in the middle and lower layers, enhancing the unstable stratification and promoted the sediment discharge. The strong wind speed in high level was strengthened and continued to extend down, and the secondary circulation in middle and low levels developed, which not only transferred and descended the dust particles, but also made the high momentum and the high potential vorticity of the upper level to pass down, then the low level jet and systems were formed and developed, maintaining the strong wind and dust weather. The negative horizontal helicity had a good correspondence with the occurrence area of dust weather. When the dust weather passing through, the dust type aerosol appeared between the surface and 4km, in addition, the concentration of PM2.5 and PM10 existed good consistence in variation and led to the level of severe pollution. Besides, the values of AOD and AQI had a good correlation in spatial and temporal distribution. The value of AOD exceeded 1 during high pollution period and dropped below 0.6 when the extent of pollution gradually decreased.
keywords:Dust  Sensible heat flux  High and low level jet  Momentum down propagation  AOD
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