Study On AOD Spatiotemporal Variation Characteristics And Influencing Factors In Wuhai Mining Area

With the rapid development of China's social economy,the process of urbanization and industrialization is advancing,the consumption of energy resources has risen sharply,the problem of air pollution caused by human factors has become increasingly serious,and it has caused serious impacts and harms on human health and the growth of animals and plants in nature..As a resource-based city dominated by the secondary industry,Wuhai,coal mining and chemical industry can make the city's economy develop rapidly,and the atmospheric environment in the region has also been seriously polluted.Aerosol optical depth(Aerosol Optical Depth,AOD)is an important factor to measure aerosol,which can effectively reflect the degree of regional air pollution.This study uses the data of MAIAC AOD products from 2003 to 2018 combined with meteorological data,statistical data,NDVI remote sensing data and land use cover data,using wavelet change analysis,trend analysis,trajectory clustering analysis,potential source analysis,correlation analysis,buffering Area analysis and other methods,first analyze the spatial and temporal evolution characteristics of AOD in Wuhai mining area and typical mining area;secondly analyze the characteristics of AOD external transport in typical haze weather process in combination with backward trajectory model;then analyze the large-scale and pixel-scale AOD of the mining area and the impact factors Correlation,to explore the main influencing factors;finally,the analysis of the mining area and different buffer sensitive areas to determine the boundary area of the AOD of the mining area.The main conclusions of this article are as follows:(1)There are obvious spatial distribution differences between the annual and quarterly AOD of Wuhai mining area from 2003 to 2018.The high annual AOD value of Wuhai mining area presents a three-stage planar distribution,and the high AOD of spring to winter moves from north to south.Distribution pattern;AOD in Wuhai mining area showed a downward trend in the past 16 years.The average AOD of Wuhai mining area has obvious periodic changes.The interannual cycle is mainly 3a and 5a,and the quarterly cycle is February,May,December and 20.The overall trend is decreasing.On the pixel scale,the AOD change in the Wuhai mining area generally shows a decreasing trend,the area with the basically unchanged area is the largest,the area with the decreasing trend is the second,and the area with the increasing trend is the smallest.(2)Among the 72 h air mass backward trajectories in Wuhai mining area,the air mass trajectory at the height of 1000 m has the longest transmission distance.From West Asia-Xinjiang-Mongolia-Inner Mongolia Alxa League to Wuhai,the air mass trajectory at the height of 100 m and 500 m is relatively short.From Xinjiang-Mongolia-Inner Mongolia Alxa League to Wuhai,the air mass sank near the ground and the air flow was not smooth,causing severe haze.The 72 h forward trajectory line passes through Ordos City to the south first,then the air mass at 1000 m height and 100 m height dissipate to the flat area in the east,and the air mass at 500 m height dissipates to the southwest area.Among the four backward trajectory clustering channels,the largest number of airflow trajectories is from Xinjiang-Gansu-Inner Mongolia Alxa LeagueWuhai direction.AOD in Wuhai mining area is affected by cross-regional transmission.The west of Wuhai,Gansu,Xinjiang and Mongolia are the main potential sources of AOD foreign transportation in Wuhai mining area,providing external transportation to AOD in Wuhai mining area.(3)On a large scale,the main influencing factors of AOD in the Wuhai mining area are artificial factors such as raw coal output and coke output.Natural factors and land-use cover factors have little effect.On the pixel scale,the area distribution of the strong positive correlation between AOD and raw coal output,coke output and air temperature in the Wuhai mining area is large,and the strong negative correlation with the wind speed and precipitation of natural factors is concentrated and distributed in large areas in the south and middle..(4)The ratio p between the urban scale of the Wuhai mining area and the small-scale eastern mining area and the Wuda mining area of the typical mining area gradually decreases with the increase of the sensitive area,and the impact of the mining area on the surrounding environment gradually weakens.The most significant reduction in the range of 2km~4km,25 km The sensitive area and the mining area within the range have significant correlation,and the correlation gradually decreases as the range of the sensitive area increases.