Validation of tropospheric NO2 column measurements of GOME-2A and OMI using MAX-DOAS and direct sun network observations
Abstract. Multi-axis differential optical absorption spectroscopy (MAX-DOAS) and direct sun NO2 vertical column network data are used to investigate the accuracy of tropospheric NO2 column measurements of the GOME-2 instrument on the MetOp-A satellite platform and the OMI instrument on Aura. The stu...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
18 November
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| In: |
Atmospheric measurement techniques
Year: 2020, Volume: 13, Issue: 11, Pages: 6141-6174 |
| ISSN: | 1867-8548 |
| DOI: | https://doi.org/10.5194/amt-13-6141-2020 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/https://doi.org/10.5194/amt-13-6141-2020 Verlag, lizenzpflichtig, Volltext: https://amt.copernicus.org/articles/13/6141/2020/ 
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| Author Notes: | Gaia Pinardi, Michel Van Roozendael, François Hendrick, Nicolas Theys, Nader Abuhassan, Alkiviadis Bais, Folkert Boersma, Alexander Cede, Jihyo Chong, Sebastian Donner, Theano Drosoglou, Anatoly Dzhola, Henk Eskes, Udo Frieß, José Granville, Jay R. Herman, Robert Holla, Jari Hovila, Hitoshi Irie, Yugo Kanaya, Dimitris Karagkiozidis, Natalia Kouremeti, Jean-Christopher Lambert, Jianzhong Ma, Enno Peters, Ankie Piters, Oleg Postylyakov, Andreas Richter, Julia Remmers, Hisahiro Takashima, Martin Tiefengraber, Pieter Valks, Tim Vlemmix, Thomas Wagner, and Folkard Wittrock |
| Summary: | Abstract. Multi-axis differential optical absorption spectroscopy (MAX-DOAS) and direct sun NO2 vertical column network data are used to investigate the accuracy of tropospheric NO2 column measurements of the GOME-2 instrument on the MetOp-A satellite platform and the OMI instrument on Aura. The study is based on 23 MAX-DOAS and 16 direct sun instruments at stations distributed worldwide. A method to quantify and correct for horizontal dilution effects in heterogeneous NO2 field conditions is proposed. After systematic application of this correction to urban sites, satellite measurements are found to present smaller biases compared to ground-based reference data in almost all cases. We investigate the seasonal dependence of the validation results as well as the impact of using different approaches to select satellite ground pixels in coincidence with ground-based data. In optimal comparison conditions (satellite pixels containing the station) the median bias between satellite tropospheric NO2 column measurements and the ensemble of MAX-DOAS and direct sun measurements is found to be significant and equal to −34% for GOME-2A and −24% for OMI. These biases are further reduced to −24% and −18% respectively, after application of the dilution correction. Comparisons with the QA4ECV satellite product for both GOME-2A and OMI are also performed, showing less scatter but also a slightly larger median tropospheric NO2 column bias with respect to the ensemble of MAX-DOAS and direct sun measurements. |
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| Item Description: | Im Titel ist "2" in NO2 tiefgestellt Gesehen am 08.02.2020 |
| Physical Description: | Online Resource |
| ISSN: | 1867-8548 |
| DOI: | https://doi.org/10.5194/amt-13-6141-2020 |