| China’s economy has developed rapidly since the Reform and opening up.However,with the advancement of urbanization and industrialization,many environmental problems have also arisen,which has also aroused great concern.This article takes the GBA(Guangdong-Hong Kong-Macao Greater Bay Area)as an example to study this phenomenon.The Guangdong-Hong Kong-Macao Greater Bay Area is one of the four largest bay areas in the world,it has the characteristics of a developed economy,a large population,a sensitive climate,and a fragile ecology.At the same time,the research on the atmospheric environment and absorptive aerosols index(Absorbable aerosol index)is still blank.So it is necessary for us to study the quality of the atmospheric environment.This paper uses the daily products of OMAERUV data from2005 to 2019 to study the temporal and spatial distribution characteristics of the absorptive aerosol index in the Guangdong-Hong Kong-Macao Greater Bay Area,and then uses methods such as Standard deviation analysis,spatial autocorrelation analysis,Theil-Sen Median trend analysis and Mann-Kendall test,Hurst index,backward trajectory and cluster analysis to reveal the change trend and space of the absorptive aerosol index in the Greater Bay Area within 15 years.The correlation between absorbable aerosol index and natural and anthropogenic factors was analyzed to provide reference for regional air pollution control.The main conclusions are as follows:(1)The annual average value of the absorbent aerosol index in the Guangdong-Hong Kong-Macao Greater Bay Area has shown an increasing trend,with an average annual increase of 4.5%.The largest increase occurred in 2017,which was0.185.The maximum value of the absorptive aerosol index of 0.986 also appeared in2017 year.The spatial distribution of the annual average value of the absorptive aerosol index presents the characteristics of high in the central region and low in the southeast and northwest regions.Guangzhou、Foshan、Jiangmen and most areas of Zhongshan have always been high-value areas(AAI>0.4).The western part of Jiangmen City,the eastern part of Dongguan and Shenzhen,the southern part of Zhaoqing City and Hong Kong are at a medium level(0<AAI<0.4),while Huizhou City and the northern part of Zhaoqing vary within the range of AAI<0.4.(2)The seasonal distribution characteristics of the Absorbable Aerosol Index value in the Guangdong-Hong Kong-Macao Greater Bay Area:spring was the highest,followed by winter and autumn,and the lowest in summer.In terms of spatial distribution,the surrounding area with Guangzhou as the center in the Greater Bay Area was the high value area of the four seasons:In the spring,the total absorptive aerosol index of the Greater Bay Area was ranked 6th;in summer,the Greater Bay Area reaches the lowest value among the four seasons;the value of the absorptive aerosol index in autumn begins to rise,at this time,the entire area of the Greater Bay Area The absorptive aerosol index value was mainly 2～3 grades;in winter,the absorptive aerosol index value of the Greater Bay Area reaches 2～5 grades.(3)The overall stability of the absorptive aerosol index value in the Greater Bay Area presents a distribution pattern in which the east and west ends are clustered,and the middle part was scattered,with significant differences in height.The regions with poor stability and worse stability were mainly distributed in Guangzhou,Foshan,Zhongshan,Zhuhai,Dongguan and the western part of Shenzhen,and the regions with good stability and better stability were mainly distributed in Zhaoqing City and Huizhou City.The AAI stable area was the transition zone from the poor and worse stable area to the good stable area.These areas were less disturbed by human activities and natural factors than the poor stable and worse stable areas.(4)The average goodness-of-fit R~2 between the monthly average value of the absorptive aerosol index,the monthly average precipitation,and the monthly average temperature were 0.812 and 0.886,showing a significant negative correlation respectively.This showed that precipitation played a role in diluting and scouring absorptive aerosols,and rising temperatures also aggravated the vertical convection of the atmosphere,which was conducive to the diffusion of atmospheric pollutants.The GDP of the Greater Bay Area and the value of the primary,secondary,and tertiary industries had a significant correlation with the AAI value.The correlation coefficients were 0.946,0.847,0.931,and-0.549.Among them,the AAI value had a significant negative correlation with the proportion of the tertiary industry(service industry,tourism),which showed that as the proportion of the tertiary industry increaseing,the AAI value appeared to decrease.There was a very significant positive correlation between the number of motor vehicles and industrial exhaust emissions and AAI(p<0.01),and the average goodness of fit R~2 reached 0.894 and 0.919,respectively,indicating that the number of motor vehicles directly leaded to vehicle exhaust emissions.The increase in the amount had further affected the increase of the AAI value;industrial waste gas also had an important contribution to the AAI value of the Greater Bay Area.(5)NDVI can reflect the metabolic intensity of vegetation,and vegetation can retain and filter dust aerosols and other particulate matter,thereby reducing the concentration of absorptive aerosols to a certain extent.From the perspective of the normalized vegetation index and the AAI value,the areas negatively correlated with the AAI value were mainly distributed in Guangzhou,Foshan,and Dongguan,and the correlations mostly vary between-1 and 0;the positively correlated areas were distributed in Guangzhou,Foshan,and Dongguan.In areas with high vegetation coverage such as Zhaoqing City and Huizhou City,the correlation was between 0 and 1,indicating that areas with high NDVI values had low AAI values.The correlation between AAI and NDVI had passed the confidence test(p<0.05)The grid point data reached 68.42%.(6)In spring,the northwest airflow moved the fastest and had the longest transportation distance,followed by the western airflow,while the eastern airflow was the slowest;in summer and autumn,the airflow came from the northwest and the west;in winter,the airflow trajectory could be roughly divided into three types:Northwest airflow,northern airflow and eastern airflow,the northwest route had the highest transport height(57.29%),followed by the lowest transport height(34.38%).The distribution of the backward trajectory was basically consistent with the distribution of the PSCF value.Pollutants in the northern region followed the cold air southward to affect the Greater Bay Area.The airflow trajectory and the spatial distribution of the PSCF both indicated that the main source of contribution to excess air pollutants in the Greater Bay Area was provided by local sources.In addition,the potential contributions of Taiwan,Fujian,Jiangxi and other places were also relatively large.(7)Based on the pixel-based spatial correlation calculation method,the correlation between the ozone column concentration and the absorptive aerosol index showed that the spatial distribution was in Zhaoqing,Foshan,Dongguan,and Shenzhen,while the negatively correlated area appeared in Guangzhou.Central China,Zhongshan City,eastern Hong Kong,and most areas of Huizhou City.The population in this region closed to the harbor and the ozone concentration was also lower than that in the western region.In summary,the change of absorptive aerosol index was related to the change of total ozone in addition to the change of absorptive aerosol concentration itself. |
PDF Full Text Request