The Spatial And Temporal Characteristics Of Atmospheric Aerosol And Its Environmental Effects Over The Belt And Road

In recent years,the problem of air pollution has become increasingly prominent.Aerosol has become the main factor in the study of air pollution.Although aerosol is relatively low in the atmosphere,as an important part of the earth-atmosphere-ocean system,it has an important impact on the climate,environment and human health.The Belt and Road is the most severe and concentrated aerosol pollution area in the world.Therefore,it is of great significance to study and analyze the temporal and spatial variation characteristics of aerosol and its environmental effects in the region,not only to fully grasp the regional distribution and changes of air pollution,but also to provide some theoretical basis for the sustainable development of atmospheric environment.Based on MODIS,OMI and TRMM multi-source Satellite remote sensing data,this paper makes a comprehensive analysis of the temporal and spatial variation characteristics of aerosol and its environmental effects over the Belt and Road by means of remote sensing,geography and statistics.Firstly,Aerosol Optical Depth(AOD),Angstrom Exponent ?(AE)and UV Aerosol Index(UVAI)were used to analyze the temporal and spatial distribution characteristics of aerosol in the Belt and Road and the typical high pollution area.Then,it discusses the impact of aerosols on atmospheric environment based on Cloud Fraction(CF),Cloud Optical Depth(COD),Cloud Effective Particle Radius Liquid or Ice(CERL/ CERI),Cloud Top Temperature(CTT),Cloud Top Pressure(CTP)and precipitation data.Finally,the Arabian Sea as a typical sea area is study to explores the impact of aerosols on the marine environment combined with chlorophyll data(Chl-a).The main conclusions are as follows:(1)The distribution of AOD over the Belt and Road from 2003 to 2017 are as follows: the area of high AOD over land is mainly distributed in areas where mostly desert dust sources and concentrated of human activities,including eastern China,Xinjiang,northern India Peninsula,central and western Africa,and Arabian Peninsula.The area of high AOD over sea is located in the coastal area near the eastern part of China,the Arabian Sea,the Bay of Bengal,and the west coast of Africa.Moreover,the area of high AOD over sea is significantly affected by land sources.The seasonal differences of regional AOD are obvious,and the AOD in spring and summer is higher than that in autumn and winter.In the past 15 years,the AOD has increased significantly in the Arabian Sea and the Bay of Bengal,while decreased significantly over the sea area of eastern China.The AOD has been significantly different over the land,it has increased significantly in the Indian Peninsula,Central Russia,Arabia,Northern Africa and Central Asia while decreased significantly in Eastern China.In addition,air pollution has improved in recent years.(2)The distribution characteristics of AE over the Belt and Road from 2003 to 2017 are as follows: AE values less than 1 are mostly concentrated in desert areas with frequent dust storms,and there are more dust aerosol with coarse particles.The AE values greater than 1 mainly occur in densely populated and industrially developed areas,with a large number of artificial aerosols with fine particles.(3)The distribution characteristics of UVAI over the Belt and Road from 2005 to 2017 are as follows: the absorbing aerosol is widely distributed in this area,and the maximum of UVAI is concentrated in Sahara desert,Arabia Peninsula and Taklimakan desert area.Non-absorbable aerosols exist in all seasons,relatively few in spring and winter,but more in summer and autumn.Among them,non-absorbable aerosols are mainly distributed in the Qinghai-Tibet Plateau and southwestern China in summer,and non-absorbable aerosols are mostly distributed in the tropical ocean in autumn.(4)For the three high-pollution areas on the land,the area 1(Eastern China)is mainly affected by human activities,and anthropogenic aerosols are dominated.Therefore,fine-grained pollutants are of the majority and AE values are larger.In winter,the absorption of aerosol is widely distributed,while in summer,due to more precipitation,the area of absorbing aerosol is less,and there is a nonabsorbent aerosol.The area 2(India-Pakistan border)is mainly affected by desert dust and human activities,and AOD is largest in summer.The AE value is less than 1 in spring and summer.The variation of regional UVAI is relatively stable,and the absorbing aerosols is more widely distributed.The area 3(Midwest Africa)is mainly affected by sand and dust and dust aerosol is dominant.In spring,AOD and UVAI are both the largest while AE is the smallest.Besides,aerosols are higher in spring and summer than in autumn and winter.(5)The spatial and temporal distribution of aerosol has a significant impact on the atmospheric environment.It is found that there is a close relationship between AOD and cloud and precipitation.In the high AOD region which are eastern China,Indian Peninsula,northern Africa and the Arabian Sea,CF,COD and precipitation increase with the increase of AOD,while CTT and CTP decrease with the increase of AOD.However,in the central and Western Africa,CF,COD and precipitation decrease with the increase of AOD,while CTT and CTP increase with the increase of AOD,which may be due to the complexity of aerosol radiation effects.The relationship between CER and AOD is more complicated.In the same region,CERI is larger than CERL.The response of AOD to CERI is more obvious,and they are almost negatively correlated,while AOD and CERL are positively correlated in Eastern China and Indian Peninsula.(6)The marine aerosol has certain influence on the marine environment.The results showed that the spatial distributions of AOD and Chl-a changed more significantly with the seasons in the Arabian Sea,and generally showed a gradual decrease from offshore to the open seas.The AOD was higher in summer than spring,and in winter was higher than that in autumn.The specific performance of Chl-a was higher in autumn and winter but lower in spring and summer,and its variability was high.From the correlation coefficient analysis between AOD and Chl-a in spring and winter,the correlation between AOD and Chl-a was significantly in the northwestern Arabian Sea,and it tends to gradually decrease from north to south and from the coast to the center of the sea.