Analysis of variations and trends of the NO2 slant column abundance obtained by DOAS measurements at Stara Zagora and at NDACC European mid-latitude stations in comparison with subtropical stations

Werner, R.; Valev, Dimitar; Atanassov, Atanas Marinov; Guineva, V.; Kirillov, A. S.

doi:10.1016/j.jastp.2013.01.016

Cited by 8 publications

(6 citation statements)

References 41 publications

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“…Эти предикторы представляют в регрессионной модели основные важные процессы, оказывающие влияние на изменчивость стратосферных примесей. В различных комбинациях они использовались при анализе трендов NO 2 [7,[16][17][18][19][20][21].…”

Section: метод решенияunclassified

Аccounting for autocorrelation in a linear regression problem on an example of analysis of atmospheric column NO2 content

Груздев

2019

Известия Российской академии наук. Физика атмосферы и океана

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A method is proposed for taking into account a serial correlation (an autocorrelation) of data in a linear regression problem, which allows accounting for the autocorrelation on long scales. A residual series is presented as an autoregressive process of an order, k, that can be much larger than 1, and the autocorrelation function of the processes is calculated by solving the system of the Yule–Walker equations. Given the autocorrelation function, the autocorrelation matrix is constructed which enters the formulas for estimates of regression coefficients and their errors. The efficiency of the method is demonstrated on the base of the multiple regression analysis of data of 26-year measurements of the column NO2 contents at the Zvenigorod Research Station of the Institute of Atmospheric Physics. Estimates of regression coefficients and their errors depend on the autoregression order k. At first the error increases with increasing k. Then it approaches its maximum and thereafter begins to decrease. In the case of NO2 at the Zvenigorod Station the error more than doubled in its maximum compared to the beginning value. The decrease in the error after approaching the maximum stops if k approaches the value such that the autoregressive process of this order allows accounting for important features of the autocorrelation function of the residual series. Estimates have been obtained of seasonally dependent linear trends and effects on NO2 of nature factors such that the 11-year solar cycle, the quasi-biennial oscillation, the North Atlantic Oscillation and other.

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Section: метод решенияunclassified

Аccounting for autocorrelation in a linear regression problem on an example of analysis of atmospheric column NO2 content

Груздев

2019

Известия Российской академии наук. Физика атмосферы и океана

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“…Out of several air pollutants, photochemical oxidants are amongst large group in which NO 2 has adverse impact on environment and human health [11], considered as the second most harmful pollutant after PM 10 [12]. Pak-EPA also declared it second most dangerous air pollutant in five big cities of Pakistan such as Lahore, Islamabad, Peshawar, Quetta and Karachi in 2006 [8].…”

Section: Introductionmentioning

confidence: 99%

“…Tropospheric nitrogen oxides (NO x : NO+NO 2 ) converted into NO 2 by the help of oxidation [12] which plays significant role in formation of secondary pollutants [13] thus cause environmental acidification [10]. NO 2 is originated from both primary sources and secondary transformation in the atmosphere [14].…”

Section: Introductionmentioning

confidence: 99%

Nitrogen Dioxide Monitoring In Urban Areas of Lahore, Pakistan

Bilal¹

2022

AJEE

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Nitrogen dioxide (NO2) plays significant role in atmospheric chemistry mainly in secondary air pollutants formation which consequently result in environmental acidification. It has adverse impact on human health and considered as the second most harmful air pollutant after PM10 in major cities of Pakistan including Lahore. In this study, 15 major urban sites of Lahore with respect to vehicular flow were focused during rush hours from 1:30 pm to 9:30 pm for the monitoring of NO2 level. Chemiluminescence technique was applied to identify NO2 concentrations by using Horiba APNA-370 monitor. For sampling, four months of winter season November 2016 to February 2017 were selected and measured monthly average mean values; associated meteorological conditions like temperature, wind speed, rainfall and relative humidity were also monitored. A spatial distribution map of different locations for NO2 concentrations was developed by using geostatistical tool ArcGIS. The highest NO2 values near the main roads were mainly due to intense traffic flow and vehicular emissions unlike residential and commercial locations. Moreover, the NO2 level exceeded the NEQS standards at most of the sampling points during study. Therefore, it is mandatory to take desired steps in order to develop effective mechanism to control air pollution before it becomes a serious hazard for human beings living in urban areas.

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“…However, whilst surface air quality monitors and satellites often benefit from long-term records, accurate multidecennial data sets from ground-based spectrometers are not yet widely available (Wang et al, 2020;Gruzdev and Elokhov, 2021). Such series are also beneficial for assessing trends in the NO 2 stratospheric concentration (Gruzdev, 2009;Werner et al, 2013), e.g. for climate studies, and for evaluating the abatement effects on the tropospheric loads resulting from environmental policies and emission controls, vehicle fleet renovation, and even worldwide crises such as the recent (2008) economic recession or the confinement due to the SARS-CoV-2 pandemic (Castellanos and Boersma, 2012;Russell et al, 2012;Hilboll et al, 2013;Vrekoussis et al, 2013;Bassani et al, 2021;Diémoz et al, 2021;Macdonald et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Advanced NO<sub>2</sub> retrieval technique for the Brewer spectrophotometer applied to the 20-year record in Rome, Italy

Diémoz

Siani

Casadio³

et al. 2021

Earth Syst. Sci. Data

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Abstract. A re-evaluated data set of nitrogen dioxide (NO2) column densities over Rome for the years 1996 to 2017 is here presented. This long-term record is obtained from ground-based direct sun measurements with a MkIV Brewer spectrophotometer (serial number #067) and further reprocessed using a novel algorithm. Compared to the original Brewer algorithm, the new method includes updated NO2 absorption cross sections and Rayleigh scattering coefficients, and it accounts for additional atmospheric compounds and instrumental artefacts, such as the spectral transmittance of the filters, the alignment of the wavelength scale, and internal temperature. Moreover, long-term changes in the Brewer radiometric sensitivity are tracked using statistical methods for in-field calibration. The resulting series presents only a few (about 30) periods with missing data longer than 1 week and features NO2 retrievals for more than 6100 d, covering nearly 80 % of the considered 20-year period. The high quality of the data is demonstrated by two independent comparisons. In the first intensive campaign, Brewer #067 is compared against another Brewer (#066), recently calibrated at the Izaña Atmospheric Observatory through the Langley method and there compared to reference instrumentation from the Network for the Detection of Atmospheric Composition Change (NDACC). Data from this campaign show a highly significant Pearson's correlation coefficient of 0.90 between the two series of slant column densities (SCDs), slope 0.98 and offset 0.05 DU (Dobson units; 1.3×1015 molec.cm-2). The average bias between the vertical column densities is 0.03 DU (8.1×1014 molec.cm-2), well within the combined uncertainty of both instruments. Brewer #067 is also independently compared with new-generation instrumentation, a co-located Pandora spectrometer (#117), over a 1-year-long period (2016–2017) at Sapienza University of Rome, showing linear correlation indices above 0.96 between slant column densities, slope of 0.97, and offset of 0.02 DU (5.4×1014 molec.cm-2). The average bias between vertical column densities is negligible (−0.002 DU or -5.4×1013 molec.cm-2). This, incidentally, represents the first intercomparison of NO2 retrievals between a MkIV Brewer and a Pandora instrument. Owing to its accuracy and length, the Brewer data set collected in Rome can be useful for satellite calibration/validation exercises, comparison with photochemical models, and better aerosol optical depth estimates (NO2 optical depth climatology). In addition, it can be employed to identify long-term trends in NO2 column densities in a metropolitan environment, over two decades witnessing important changes in environmental policies, emission loads and composition, and the effect of a worldwide economic recession, to offer just a few examples. The method can be replicated on the more than 80 MkIV spectrophotometers operating worldwide in the frame of the international Brewer network. The NO2 data set described in this paper can be freely accessed at https://doi.org/10.5281/zenodo.4715219 (Diémoz and Siani, 2021).

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Analysis of variations and trends of the NO2 slant column abundance obtained by DOAS measurements at Stara Zagora and at NDACC European mid-latitude stations in comparison with subtropical stations

Cited by 8 publications

References 41 publications

Аccounting for autocorrelation in a linear regression problem on an example of analysis of atmospheric column NO2 content

Аccounting for autocorrelation in a linear regression problem on an example of analysis of atmospheric column NO2 content

Nitrogen Dioxide Monitoring In Urban Areas of Lahore, Pakistan

Advanced NO<sub>2</sub> retrieval technique for the Brewer spectrophotometer applied to the 20-year record in Rome, Italy

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Analysis of variations and trends of the NO2 slant column abundance obtained by DOAS measurements at Stara Zagora and at NDACC European mid-latitude stations in comparison with subtropical stations

Cited by 8 publications

References 41 publications

Аccounting for autocorrelation in a linear regression problem on an example of analysis of atmospheric column NO2 content

Аccounting for autocorrelation in a linear regression problem on an example of analysis of atmospheric column NO2 content

Nitrogen Dioxide Monitoring In Urban Areas of Lahore, Pakistan

Advanced NO&lt;sub&gt;2&lt;/sub&gt; retrieval technique for the Brewer spectrophotometer applied to the 20-year record in Rome, Italy

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Advanced NO<sub>2</sub> retrieval technique for the Brewer spectrophotometer applied to the 20-year record in Rome, Italy