Multi-source Satellite Remote Sensing Analysis Of Regional Pollution Gas Characteristics In China

Since China entered the 21st century,the process of industrialization and urbanization has accelerated,the social and economic development has been rapid,and the emission of pollutant gases into the atmosphere from human activities has been increasing,which can cause a series of climate and environmental effects and thus seriously endanger human health.In this work,we used OMI/MLS tropospheric O₃ column concentration data and OMI,OMPS,and TROPOMI tropospheric NO₂ and SO₂ column concentration data.Based on the data applicability analysis comparing to ground-based observations,we analyzed the long-term trends,seasonal and monthly variations,and epidemic period variations of pollutant gases in China,and the correlation between the pollutant gases and various influencing factors.The main conclusions are as follows.(1)In the statistical correlation between the tropospheric O₃ column concentration in OMI/MLS inversion and the measured ground-based concentration,68.1%of the cities passed the significance test.Over 80%of the cities passed the significance analysis in the statistical correlation between the tropospheric NO₂ and ground-based concentration in OMI,OMPS and TROPOMI inversion,and OMI had the best correlation,but in UCS and BTH region TROPOMI is better than the other two.In addition,the deviation high value area of remote sensing of the three data is in eastern China,OMI>OMPS>TROPOMI.Finally,the correlation between tropospheric SO₂column concentrations and measured ground concentrations of OMI and OMPS inversions pass the significance test in 63.5%and 53.2%of cities,respectively.Overall OMI is higher than OMPS,and the overestimation area is mainly distributed in northern China,while it is lower than OMPS in southern China.(2)The tropospheric O₃ shows an upward trend,tropospheric NO₂ shows a weak upward trend,and tropospheric SO₂ shows an eastward and westward trend from 2005to 2020 in the Chinese region.The seasonal trend of tropospheric O₃ is:summer>spring>autumn>winter,and the high value areas in summer are distributed in the North China Plain and Xinjiang Autonomous Region,while the Qinghai-Tibet Plateau is at a low level throughout the year.The seasonal trends of tropospheric NO₂and SO₂ are:winter>autumn>spring>summer,and the high value areas are mainly distributed in BTH region,Urumqi and Henan-Hebei area.Overall,O₃,NO₂ and SO₂tend to have higher concentrations in areas with high human activities,and their distribution and trends are all roughly similar to those of their emissions or precursor emissions.In addition,wind fields,precipitation and solar radiation,as important conditions for their chemical mechanisms,play an important role in their changes.During the national epidemic closed management,there was a more obvious decrease in tropospheric NO₂ and SO₂ column concentrations,which lasted for two weeks and then started to rebound in mid-February.