Temporal And Spatial Characteristics And The Influence Factor Analysis Of Haze Days With Different Levels In Liaoning Province

Haze is a weather phenomenon which has attracted much attention in recent years.Liaoning Province,as an vital old industrial base,haze weather phenomenon occurs frequently in recent years,which has reduced visibility,increased air pollution,and had a strong impact on transportation,health,industrial and agricultural production.It is of great theoretical and practical significance to strengthen the research on the formation mechanism and temporal and spatial characteristics of haze weather.The article used hourly weather observation data from 14 cities and hourly data of pollutants'concentrations from 2014 to 2016 in Liaoning.The latest classification standards are used to classify the haze levels,and analyze temporal and spatial characteristics of different levels of haze weather.Taking Shenyang as the representative,using correlation analysis and regression analysis methods to research the impact of meteorological elements and pollution factors on visibility in 2016.Using the Back-trajectory model and cluster analysis method,the relationship between different transport effects and the occurrence rate of haze are analyzed from 2014 to 2015 in Liaoning.Using a heavy pollution weather process in Liaoning Province,the changes in meteorological elements during this hazy weather are analyzed based on satellite remote sensing monitoring data,meteorological data,environmental monitoring data,and sounding data.At the same time,using the back-trajectory model to analyze the pollutions'transport path,and the formation mechanism of the hazy weather are obtained.The main conclusions are as follows:?1?The results indicate that for temporal variation of haze day,the maximum mean monthly haze day in Liaoning province occurs in January,and the minimum value in June.Haze days are mainly concentrated in winter and autumn,accounting for over 70%of annual total,followed by summer and the in spring.The highest averaged number of annual haze days in Liaoning Province is in 2014,and is in a decreasing trend.Mild and moderate haze is also in a decreasing trend,while severe and severity haze haze have no significant change.The number of mild days are the highest,and severe and severity haze was less.From the point of view of spatial distribution,the number of monthly,seasonal,annual haze days are more in the central regions,and less on both sides.The spatial difference is significant,there is a high-value region located in Shenyang City and two sub-high-value regions in Jinzhou City and Chaoyang City.Regional spatial distribution is different in different periods.?2?Visibility,relative humidity and six pollutants concentration have obvious monthly and daily variation characteristic.Among the six pollutants,the correlation between visibility and PM_2.5.5 is the highest,and the correlation coefficient is-0.71,followed by the correlation coefficient with PM₁₀.Among the meteorological factors,the correlation with relative humidity is the highest,and the correlation coefficient is-0.57.In different seasons,the correlation between visibility and PM_2.5.5 is higher than that of PM₁₀,and the correlation between visibility and particulate matter is greatest in winter.?3?The occurrence rate and the level of haze corresponding to the backward trajectory in different directions are obviously different.In the four seasons of Liaoning Province,the local and inter-regional urban transport are the main factors during the haze on four seasons.The regional transport includes pollutants from Beijing-Tianjin-Hebei,and Shandong Province,which are transported to the Liaoning region under the influence of the southwest airstream,and from Heilongjiang and Jilin areas which are transported to the Liaoning area under the influence of the northerly airsteam in autumn and winter.?4?The results showed that the main pollution component were gas pollutants?CO,NO₂?and particulate matter(PM_2.5,PM₁₀)produced by straw burning in Heilongjiang and Jilin.The atmospheric trajectory analysis showed the northerly winds provided favorable weather conditions for pollutants transportation.Atmospheric stratification stability,light wind and high humidity conditions provided advantage meteorological conditions for the heavy pollution weather developing and lasting.There is a deep inversion layer near the ground,causing vertical and horizontal diffusion of pollutants suppressed and accumulated in Liaoning.At the same time,the large-scale precipitation increased humidity which led to pollutants concentrations increase and expand the degree of air pollution.