OMI total bromine monoxide (OMBRO) data product: algorithm, retrieval and measurement comparisons
This paper presents the retrieval algorithm for the operational Ozone Monitoring Instrument (OMI) total bromine monoxide (BrO) data product (OMBRO) developed at the Smithsonian Astrophysical Observatory (SAO) and shows comparisons with correlative measurements and retrieval results. The algorithm is...
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2019
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This paper presents the retrieval algorithm for the operational Ozone Monitoring Instrument (OMI) total bromine monoxide (BrO) data product (OMBRO) developed at the Smithsonian Astrophysical Observatory (SAO) and shows comparisons with correlative measurements and retrieval results. The algorithm is based on direct nonlinear least squares fitting of radiances from the spectral range 319.0–347.5 nm . Radiances are modeled from the solar irradiance, attenuated by contributions from BrO and interfering gases, and including rotational Raman scattering, additive and multiplicative closure polynomials, correction for Nyquist undersampling and the average fitting residual spectrum. The retrieval uses albedo- and wavelength-dependent air mass factors (AMFs), which have been pre-computed using a single mostly stratospheric BrO profile. The BrO cross sections are multiplied by the wavelength-dependent AMFs before fitting so that the vertical column densities (VCDs) are retrieved directly. The fitting uncertainties of BrO VCDs typically vary between 4 and 7×10 12 molecules cm −2 ( ∼10 %–20 % of the measured BrO VCDs). Additional fitting uncertainties can be caused by the interferences from O 2 - O 2 and H 2 CO and their correlation with BrO. AMF uncertainties are estimated to be around 10 % when the single stratospheric-only BrO profile is used. However, under conditions of high tropospheric concentrations, AMF errors due to this assumption of profile can be as high as 50 %. The retrievals agree well with GOME-2 observations at simultaneous nadir overpasses and with ground-based zenith-sky measurements at Harestua, Norway, with mean biases less than <math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mn mathvariant="normal">0.22</mn><mo>±</mo><mn mathvariant="normal">1.13</mn><mo>×</mo><msup><mn mathvariant="normal">10</mn><mn mathvariant="normal">13</mn></msup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="96pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="21e81717dfc4ccb936c22a4ec884a85f"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-2067-2019-ie00001.svg" width="96pt" height="14pt" src="amt-12-2067-2019-ie00001.png"/></svg:svg> and <math xmlns="http://www.w3.org/1998/Math/MathML" id="M9" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">0.12</mn><mo>±</mo><mn mathvariant="normal">0.76</mn><mo>×</mo><msup><mn mathvariant="normal">10</mn><mn mathvariant="normal">13</mn></msup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="88pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="b0a934d14212a27333a508589a46f793"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-2067-2019-ie00002.svg" width="88pt" height="14pt" src="amt-12-2067-2019-ie00002.png"/></svg:svg> molecules cm −2 , respectively. Global distribution and seasonal variation of OMI BrO are generally consistent with previous satellite observations. Finally, we confirm the capacity of OMBRO retrievals to observe enhancements of BrO over the US Great Salt Lake despite the current retrieval setup considering a stratospheric profile in the AMF calculations. OMBRO retrievals also show significant BrO enhancements from the eruption of the Eyjafjallajökull volcano, although the BrO retrievals are affected under high SO 2 loading conditions by the sub-optimum choice of SO 2 cross sections. |
format |
Text |
author |
Suleiman, Raid M. Chance, Kelly Liu, Xiong González Abad, Gonzalo Kurosu, Thomas P. Hendrick, Francois Theys, Nicolas |
spellingShingle |
Suleiman, Raid M. Chance, Kelly Liu, Xiong González Abad, Gonzalo Kurosu, Thomas P. Hendrick, Francois Theys, Nicolas OMI total bromine monoxide (OMBRO) data product: algorithm, retrieval and measurement comparisons |
author_facet |
Suleiman, Raid M. Chance, Kelly Liu, Xiong González Abad, Gonzalo Kurosu, Thomas P. Hendrick, Francois Theys, Nicolas |
author_sort |
Suleiman, Raid M. |
title |
OMI total bromine monoxide (OMBRO) data product: algorithm, retrieval and measurement comparisons |
title_short |
OMI total bromine monoxide (OMBRO) data product: algorithm, retrieval and measurement comparisons |
title_full |
OMI total bromine monoxide (OMBRO) data product: algorithm, retrieval and measurement comparisons |
title_fullStr |
OMI total bromine monoxide (OMBRO) data product: algorithm, retrieval and measurement comparisons |
title_full_unstemmed |
OMI total bromine monoxide (OMBRO) data product: algorithm, retrieval and measurement comparisons |
title_sort |
omi total bromine monoxide (ombro) data product: algorithm, retrieval and measurement comparisons |
publishDate |
2019 |
url |
https://doi.org/10.5194/amt-12-2067-2019 https://amt.copernicus.org/articles/12/2067/2019/ |
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Norway |
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Norway |
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Eyjafjallajökull |
genre_facet |
Eyjafjallajökull |
op_source |
eISSN: 1867-8548 |
op_relation |
doi:10.5194/amt-12-2067-2019 https://amt.copernicus.org/articles/12/2067/2019/ |
op_doi |
https://doi.org/10.5194/amt-12-2067-2019 |
container_title |
Atmospheric Measurement Techniques |
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12 |
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4 |
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2067 |
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2084 |
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1766405554460164096 |
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ftcopernicus:oai:publications.copernicus.org:amt66011 2023-05-15T16:09:43+02:00 OMI total bromine monoxide (OMBRO) data product: algorithm, retrieval and measurement comparisons Suleiman, Raid M. Chance, Kelly Liu, Xiong González Abad, Gonzalo Kurosu, Thomas P. Hendrick, Francois Theys, Nicolas 2019-04-04 application/pdf https://doi.org/10.5194/amt-12-2067-2019 https://amt.copernicus.org/articles/12/2067/2019/ eng eng doi:10.5194/amt-12-2067-2019 https://amt.copernicus.org/articles/12/2067/2019/ eISSN: 1867-8548 Text 2019 ftcopernicus https://doi.org/10.5194/amt-12-2067-2019 2020-07-20T16:22:53Z This paper presents the retrieval algorithm for the operational Ozone Monitoring Instrument (OMI) total bromine monoxide (BrO) data product (OMBRO) developed at the Smithsonian Astrophysical Observatory (SAO) and shows comparisons with correlative measurements and retrieval results. The algorithm is based on direct nonlinear least squares fitting of radiances from the spectral range 319.0–347.5 nm . Radiances are modeled from the solar irradiance, attenuated by contributions from BrO and interfering gases, and including rotational Raman scattering, additive and multiplicative closure polynomials, correction for Nyquist undersampling and the average fitting residual spectrum. The retrieval uses albedo- and wavelength-dependent air mass factors (AMFs), which have been pre-computed using a single mostly stratospheric BrO profile. The BrO cross sections are multiplied by the wavelength-dependent AMFs before fitting so that the vertical column densities (VCDs) are retrieved directly. The fitting uncertainties of BrO VCDs typically vary between 4 and 7×10 12 molecules cm −2 ( ∼10 %–20 % of the measured BrO VCDs). Additional fitting uncertainties can be caused by the interferences from O 2 - O 2 and H 2 CO and their correlation with BrO. AMF uncertainties are estimated to be around 10 % when the single stratospheric-only BrO profile is used. However, under conditions of high tropospheric concentrations, AMF errors due to this assumption of profile can be as high as 50 %. The retrievals agree well with GOME-2 observations at simultaneous nadir overpasses and with ground-based zenith-sky measurements at Harestua, Norway, with mean biases less than <math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mn mathvariant="normal">0.22</mn><mo>±</mo><mn mathvariant="normal">1.13</mn><mo>×</mo><msup><mn mathvariant="normal">10</mn><mn mathvariant="normal">13</mn></msup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="96pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="21e81717dfc4ccb936c22a4ec884a85f"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-2067-2019-ie00001.svg" width="96pt" height="14pt" src="amt-12-2067-2019-ie00001.png"/></svg:svg> and <math xmlns="http://www.w3.org/1998/Math/MathML" id="M9" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">0.12</mn><mo>±</mo><mn mathvariant="normal">0.76</mn><mo>×</mo><msup><mn mathvariant="normal">10</mn><mn mathvariant="normal">13</mn></msup></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="88pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="b0a934d14212a27333a508589a46f793"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-12-2067-2019-ie00002.svg" width="88pt" height="14pt" src="amt-12-2067-2019-ie00002.png"/></svg:svg> molecules cm −2 , respectively. Global distribution and seasonal variation of OMI BrO are generally consistent with previous satellite observations. Finally, we confirm the capacity of OMBRO retrievals to observe enhancements of BrO over the US Great Salt Lake despite the current retrieval setup considering a stratospheric profile in the AMF calculations. OMBRO retrievals also show significant BrO enhancements from the eruption of the Eyjafjallajökull volcano, although the BrO retrievals are affected under high SO 2 loading conditions by the sub-optimum choice of SO 2 cross sections. Text Eyjafjallajökull Copernicus Publications: E-Journals Norway Atmospheric Measurement Techniques 12 4 2067 2084 |