摘要
利用2015-2020年萍乡市城区冬季空气质量(AQI)数据、地面气象观测资料和欧洲中期天气预报中心再分析资料,结合天气形势与大气垂直运动特点,针对空气质量明显改善、空气质量轻度改善、空气污染轻度加剧或无变化和空气污染明显加剧4类空气质量日差异性变化过程进行了天气分型研究。结果表明,冬季高压底部型出现次数最多,占比高达28.57%;其次为高压后部中层上升型和冷切变型,占比分别为20.94%和19.96%;低压倒槽中层下沉型和低压倒槽中层上升型出现次数比较接近,占比分别为11.74%和10.96%;高压后部中层下沉型出现次数最少,占比仅为7.83%。高压底部型、高压后部中层下沉型、高压后部中层上升型和低压倒槽中层下沉型的大部分过程均不利于大气污染扩散,下沉运动或弱上升运动伴有强逆温易导致空气污染明显加剧,强(弱)上升运动伴有逆温则空气质量轻度改善(空气污染轻度加剧);中层强上升运动且低层弱下沉运动、无逆温(或弱逆温)和较明显降水的条件下,极少数高压后部中层上升型的空气质量明显改善;下沉中心伸展较高的强下沉运动伴有晴好无逆温天气,近地面湍流活动加剧,中高层的干洁空气向下输送,极少数高压底部型的空气质量明显改善。低压倒槽中层上升型和冷切变型绝大部分过程利于大气污染扩散,强上升运动伴有明显降水且无逆温(或弱逆温)的条件下,空气质量明显改善;上升运动伴有较明显降水且有逆温的条件下,空气质量可能轻度改善;弱上升运动伴有强逆温的条件下,空气污染轻度加剧。
Using the Air Quality Index(AQI)data and surface meteorological observation in the urban area of Pingxiang City in the winter of 20152020,and European Center for Medium-Range Weather Forecasts(ECMWF)reanalysis data,combined with the characteristics of weather situation and atmospheric vertical motion,a synoptic classification study was conducted to study the diurnal variation of air quality in four categories,that is,significantly improved air quality,slightly improved air quality,slight aggravation or no change in air pollution,and significantly aggravated air pollution.The results indicate that,in winter,the high-pressure bottom type of weather patterns occurs most frequently,accounting for a high proportion of 28.57%,followed by the high-pressure rear mid-level ascension type(20.94%)and the cold shear type(19.96%).The frequencies of the low-pressure inverted trough mid-level subsidence type and the low-pressure inverted trough mid-level ascension type are relatively close,with proportions of 11.74%and 10.96%,respectively.The high-pressure rear mid-level subsidence type has the lowest frequency,only 7.83%.Generally,most processes of the high-pressure bottom type,the high-pressure rear mid-level subsidence type,the high-pressure rear mid-level ascension type and the low-pressure inverted trough mid-level subsidence type are unfavorable for the dispersion of atmospheric pollutants.Sinking motion or weak ascending motion with strong temperature inversion can lead to significant aggravation of air pollution.Air quality(air pollution)improves(increases)slightly with strong(weak)upward movement accompanied by temperature inversion.When there is mid-level strong ascending motion,low-level weak descending motion,no inversion(or weak inversion)and more pronounced precipitation,the high-pressure rear mid-level ascension type is hard to have a significant improvement in air quality.When the strong descending motion extends to a higher altitude,accompanied by clear weather without inversion near the ground,intensified turbulent activity near the ground,and downward transport of dry and clean air from the mid-to-upper levels,there are very few chances for the high-pressure bottom type to show a noticeable improvement in air quality.Most processes of the low-pressure inverted trough mid-level ascension type and the cold shear type are conducive to the dispersion of air pollutants.In summary,air quality can be improved significantly with the strong upward motion,accompanied by the obvious precipitation and no(or weak)temperature inversion;air quality may be mildly improved with upward motion,accompanied by obvious precipitation and temperature inversion;and air pollution aggravates slightly with weak upward motion accompanied by stronger temperature inversion.
作者
李侃
马静
叶小峰
Li Kan;Ma Jing;Ye Xiaofeng(Pingxiang Meteorological Office of Jiangxi Province,Pingxiang 337002,China;Key Laboratory of Meteorological Disaster,Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science and Technology,Nanjing 210044,China)
出处
《气象与环境科学》
2024年第3期62-71,共10页
Meteorological and Environmental Sciences
基金
国家自然科学基金青年科学基金项目(No.41805051)
江西省气象局青年人才培养项目(JX2022Q08)。
关键词
空气质量日差异性变化
大气垂直运动
天气分型
daily variation of air quality
vertical movement of atmosphere
synoptic classification
