摘要
针对春节期间燃放烟花爆竹易加剧空气污染的现实问题,该文利用2014年1-2月逐日空气质量指数(AQI)和相应时段的基本气象数据以及NCEP/NCAR再分析资料,探析了2014年春节前后陕西关中地区一次重污染天气的气象条件。主要结论如下:该次重污染过程于1月25日开始,2月5日结束,持续12 d,关中地区平均出现重度污染和严重污染各4 d,污染最严重时该区各市的AQI除了铜川外均在400以上,AQI最高值出现在1月31日的渭南,达484。究其气象成因发现,春节前的持续性高空平直纬向气流控制关中地区,地面处于两高压之间过渡区或低压区,形成非常不利于污染物扩散的环流形势场;对应低层925 h Pa存在中心值为-2×10^(-5)s^(-1)的弱辐合区,加之近地面的弱下沉气流,导致大气垂直交换差,是造成污染物堆积的直接边界层动力条件;较低的大气边界层混合高度和最大4.6~℃/100 m的贴地逆温是造成污染物积累的重要层结稳定条件。后向轨迹分析表明,该次重污染过程的污染物来源以本地排放为主,节日期间大量烟花爆竹的燃放起到了雪上加霜的作用,使得空气污染进一步加重。春节后的寒潮过境,最大风速超过10 m/s的冷空气侵入,破坏了边界层静稳天气形势,使得大气扩散能力迅速增强,对当地空气质量迅速转好起到关键性作用。
Aiming at air pollution that was intensified by fireworks setting-off during the Spring Festival, this paper intended to analyze meteorological conditions when severe air pollution happened in Guanzhong region, Shannxi Province during Spring Festival, 2014, based on the day-by-day quality index（AQI） of the period from Jan. to Feb.2014, as well as meteorological data and NCEP/NCAR re-analysis data of the corresponding period. The conclusions indicated that the pollution process in Guanzhong region lasted for 12 days from January 25 to February 5, during which four days under heavy pollution, another four days severe under pollution——AQI was above 400 in all cities within the region except for Tongchuan City when undergoing severe pollution, the maximum AQI occurred in Weinan City in January 31 with AQI of 484. According to the meteorological data, there was persistent flat zonal flow that controlled the weather of Guanzhong region before the Spring Festival and ground surface was in the transition or low pressure conditions between two high-pressure areas, which resulted in main circulation situation adverse to air pollutants diffusion. There existed lower-layer weak convergence and near-ground weak downdraft, causing poor atmospheric vertical exchange, which was the direct boundary-layer dynamic condition that led to pollutants accumulation. Furthermore, near ground inversion with maximum value of 4.6 ℃/100 m and lower mixing height of the atmosphere boundary layer resulted in stable stratification, liable to cause accumulation of pollutants. Finally, the backward trajectory analysis indicated that the local emissions were the major heavy pollution source, and setting off firecrackers and fireworks during the Spring Festival made the situation worse. However, cold wave came after the Spring Festival with maximum speed of 10 m/s so the boundary-layer quiet and stable weather condition was rapidly broken and the atmosphericdiffusion ability strengthened, which was vital for quickly getting well of air qua
作者
胡文斌
王嘉鑫
李文榜
王式功
HU Wenbin;WANG Jiaxin;Li Wenbang;WANG Shigong(Unit No. 96751 of PLA, Dalian 116600, China;School of Atmospheric Science, Chengdu University of Information Technology, Chengdu 610225, China;Shantou Air Traffic Management Station of CAAC, Shantou 515558, China)
出处
《环境科学与技术》
CAS
CSCD
北大核心
2018年第3期72-79,共8页
Environmental Science & Technology
基金
国家自然科学基金重大研究计划重点支持项目(91644226)
国家重点研发计划“全球变化及应对”重点专项(2016YFA0602004)
关键词
空气质量
AQI
关中地区
气象条件
烟花爆竹
air quality
AQI
Guanzhong region
meteorological conditions
fireworks
