Comparison of Results of Long-Term Measurements of Stratospheric and Tropospheric Column NO₂ Contents using Satellite Ozone Monitoring Instrument to Results of Ground-Based Measurements

Abstract

Results of measurements of NO2 contents in vertical columns of the stratosphere and troposphere using the Ozone Monitoring Instrument aboard the EOS–Aura satellite in 2004–2020 are compared to results of ground-based measurements at stations of the Network for the Detection of Atmospheric Composition Change (NDACC), first of all, to results of measurements at the Zvenigorod Scientific Station (ZSS) of the A.M. Obukhov Institute of Atmospheric Physics Russian Academy of Sciences. The comparison of satellite data to the ZSS data is done using the both products of satellite measurements—the stratospheric and tropospheric column NO2 contents. When comparing the data of OMI and ground-based measurements at other stations, satellite values of the NO2 content in the stratospheric column are compared to values of the total column NO2 content obtained in ground-based measurements. Correspondence between the results of satellite and ground-based measurements is characterized by the magnitude of the difference between them, linear correlation coefficients and regression coefficients. The difference has a noticeable seasonal variation. Correlation and regression coefficients depend significantly on the season. Characteristic patterns of correlation coefficient changes with latitude as well as features of correlation between satellite and ground-based data in the polar and middle latitudes of the southern hemisphere in spring have been revealed. For some stations, the dependence of the quantitative characteristics of the correspondence between the results of satellite and ground-based measurements on cloudiness has been revealed. Under cloudless conditions at the ZSS, a weakening of the correlation between satellite and ground-based values of the stratospheric NO2 content and an increase in the correlation between the values of the tropospheric NO2 content is noted. The dependence of the correspondence characteristics between the data of satellite and ground-based measurements on the level of pollution of the lower troposphere with nitrogen oxides has been revealed. The correlation between the values of the tropospheric NO2 content in the vicinity of the ZSS under strong pollution increases, while the correlation between the values of the stratospheric NO2 content decreases. Based on the results of the comparison of satellite and ground-based data, estimates of the upper threshold values of the tropospheric NO2 content at different stations is obtained. The lowest values have been obtained for polar stations, and the highest value has been obtained for the ZSS which is most susceptible to anthropogenic pollution due to its proximity to the Moscow megapolis.