Analysis of the Meteorological Conditions for Daily Variation of Air Quality in Winter in Urban Area of Pingxiang City from 2015 to 2020
Using the Air Quality Index(AQI)data and surface meteorological observation in the ur-ban area of Pingxiang City in the winter of 2015-2020,and European Center for Medium-Range Weather Forecasts(ECMWF)reanalysis data,combined with the characteristics of weather situation and atmos-pheric 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 fre-quency,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 mo-tion 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-pres-sure 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 ascen-sion type and the cold shear type are conducive to the dispersion of air pollutants.In summary,air quali-ty 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,ac-companied by obvious precipitation and temperature inversion;and air pollution aggravates slightly with weak upward motion accompanied by stronger temperature inversion.
daily variation of air qualityvertical movement of atmospheresynoptic classification
万方数据
维普
