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1. Abrupt declines in tropospheric nitrogen dioxide over China after the outbreak of COVID-19

Author

Liu, Fei, Page, Aaron, Strode, Sarah A., Yoshida, Yasuko, Choi, Sungyeon, Zheng, Bo, Lamsal, Lok N., Li, Can, Krotkov, Nickolay A., Eskes, Henk, van der A, Ronald, Veefkind, Pepijn, Levelt, Pieternel, Joiner, Joanna, and Hauser, Oliver P.

Subjects
Physics - Atmospheric and Oceanic Physics, Economics - General Economics
Abstract

China's policy interventions to reduce the spread of the coronavirus disease 2019 have environmental and economic impacts. Tropospheric nitrogen dioxide indicates economic activities, as nitrogen dioxide is primarily emitted from fossil fuel consumption. Satellite measurements show a 48% drop in tropospheric nitrogen dioxide vertical column densities from the 20 days averaged before the 2020 Lunar New Year to the 20 days averaged after. This is 20% larger than that from recent years. We relate to this reduction to two of the government's actions: the announcement of the first report in each province and the date of a province's lockdown. Both actions are associated with nearly the same magnitude of reductions. Our analysis offers insights into the unintended environmental and economic consequences through reduced economic activities., Comment: 29 pages, 11 figures

Published
2020

3. 5 years of Sentinel-5P TROPOMI operational ozone profiling and geophysical validation using ozonesonde and lidar ground-based networks.

Author

Keppens, Arno, Di Pede, Serena, Hubert, Daan, Lambert, Jean-Christopher, Veefkind, Pepijn, Sneep, Maarten, De Haan, Johan, ter Linden, Mark, Leblanc, Thierry, Compernolle, Steven, Verhoelst, Tijl, Granville, José, Nath, Oindrila, Fjæraa, Ann Mari, Boyd, Ian, Niemeijer, Sander, Van Malderen, Roeland, Smit, Herman G. J., Duflot, Valentin, and Godin-Beekmann, Sophie

Subjects
TROPOSPHERIC ozone, OZONE, LIDAR, OZONE layer, ZENITH distance, DEGREES of freedom, STRATOSPHERE
Abstract

The Sentinel-5 Precursor (S5P) satellite operated by the European Space Agency has carried the TROPOspheric Monitoring Instrument (TROPOMI) on a Sun-synchronous low-Earth orbit since 13 October 2017. The S5P mission has acquired more than 5 years of TROPOMI nadir ozone profile data retrieved from the level 0 to 1B processor version 2.0 and the level 1B to 2 optimal-estimation-based processor version 2.4.0. The latter is described in detail in this work, followed by the geophysical validation of the resulting ozone profiles for the period May 2018 to April 2023. Comparison of TROPOMI ozone profile data to co-located ozonesonde and lidar measurements used as references concludes to a median agreement better than 5 % to 10 % in the troposphere. The bias goes up to - 15 % in the upper stratosphere (35–45 km) where it can exhibit vertical oscillations. The comparisons show a dispersion of about 30 % in the troposphere and 10 % to 20 % in the upper troposphere to lower stratosphere and in the middle stratosphere, which is close to mission requirements. Chi-square tests of the observed differences confirm on average the validity of the ex ante (prognostic) satellite and ground-based data uncertainty estimates in the middle stratosphere above about 20 km. Around the tropopause and below, the mean chi-square value increases up to about four, meaning that the ex ante TROPOMI uncertainty is underestimated. The information content of the ozone profile retrieval is characterised by about five to six vertical subcolumns of independent information and a vertical sensitivity (i.e. the fraction of the information that originates from the measurement) nearly equal to unity at altitudes from about 20 to 50 km, decreasing rapidly at altitudes above and below. The barycentre of the retrieved information is usually close to the nominal retrieval altitude in the 20–50 km altitude range, with positive and negative offsets of up to 10 km below and above this range, respectively. The effective vertical resolution of the profile retrieval usually ranges within 10–15 km, with a minimum close to 7 km in the middle stratosphere. Increased sensitivities and higher effective vertical resolutions are observed at higher solar zenith angles (above about 60°), as can be expected, and correlate with higher retrieved ozone concentrations. The vertical sensitivity of the TROPOMI tropospheric ozone retrieval is found to depend on the solar zenith angle, which translates into a seasonal and meridian dependence of the bias with respect to reference measurements. A similar although smaller effect can be seen for the viewing zenith angle. Additionally, the bias is negatively correlated with the surface albedo for the lowest three ozone subcolumns (0–18 km), despite the albedo's apparently slightly positive correlation with the retrieval degrees of freedom in the signal. For the 5 years of TROPOMI ozone profile data that are available now, an overall positive drift is detected for the same three subcolumns, while a negative drift is observed above (24–32 km), resulting in a negligible vertically integrated drift. [ABSTRACT FROM AUTHOR]

Published
2024
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4. Investigating expanding air pollution and climate change on the African continent

Author

Levelt, Pieternel, primary, Marais, Eloise A, additional, Worden, Helen, additional, Tang, Wenfu, additional, Martinez-Alonso, Sara, additional, Edwards, David, additional, Eskes, Henk, additional, Veefkind, Pepijn, additional, Brown, Steve, additional, Gameli Hodoli, Collins, additional, Felix Hughes, Allison, additional, Lefer, Barry, additional, Sheldon, Drobot, additional, and Westervelt, Dan, additional

Published
2024
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7. Tropical tropospheric ozone distribution and trends from in situ and satellite data

Author

Gaudel, Audrey, primary, Bourgeois, Ilann, additional, Li, Meng, additional, Chang, Kai-Lan, additional, Ziemke, Jerald, additional, Sauvage, Bastien, additional, Stauffer, Ryan M., additional, Thompson, Anne M., additional, Kollonige, Debra E., additional, Smith, Nadia, additional, Hubert, Daan, additional, Keppens, Arno, additional, Cuesta, Juan, additional, Heue, Klaus-Peter, additional, Veefkind, Pepijn, additional, Aikin, Kenneth, additional, Peischl, Jeff, additional, Thompson, Chelsea R., additional, Ryerson, Thomas B., additional, Frost, Gregory J., additional, McDonald, Brian C., additional, and Cooper, Owen R., additional

Published
2024
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8. Supplementary material to "Tropical tropospheric ozone distribution and trends from in situ and satellite data"

Author

Gaudel, Audrey, primary, Bourgeois, Ilann, additional, Li, Meng, additional, Chang, Kai-Lan, additional, Ziemke, Jerald, additional, Sauvage, Bastien, additional, Stauffer, Ryan M., additional, Thompson, Anne M., additional, Kollonige, Debra E., additional, Smith, Nadia, additional, Hubert, Daan, additional, Keppens, Arno, additional, Cuesta, Juan, additional, Heue, Klaus-Peter, additional, Veefkind, Pepijn, additional, Aikin, Kenneth, additional, Peischl, Jeff, additional, Thompson, Chelsea R., additional, Ryerson, Thomas B., additional, Frost, Gregory J., additional, McDonald, Brian C., additional, and Cooper, Owen R., additional

Published
2024
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9. Five years of Sentinel-5p TROPOMI operational ozone profiling and geophysical validation using ozonesonde and lidar ground-based networks

Author

Keppens, Arno, primary, Di Pede, Serena, additional, Hubert, Daan, additional, Lambert, Jean-Christopher, additional, Veefkind, Pepijn, additional, Sneep, Maarten, additional, De Haan, Johan, additional, ter Linden, Mark, additional, Leblanc, Thierry, additional, Compernolle, Steven, additional, Verhoelst, Tijl, additional, Granville, José, additional, Nath, Oindrila, additional, Fjaeraa, Ann Mari, additional, Boyd, Ian, additional, Niemeijer, Sander, additional, Van Malderen, Roeland, additional, Smit, Herman G. J., additional, Duflot, Valentin, additional, Godin-Beekmann, Sophie, additional, Johnson, Bryan J., additional, Steinbrecht, Wolfgang, additional, Tarasick, David W., additional, Kollonige, Debra E., additional, Stauffer, Ryan M., additional, Thompson, Anne M., additional, Dehn, Angelika, additional, and Zehner, Claus, additional

Published
2024
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10. New Era of Air Quality Monitoring from Space : Geostationary Environment Monitoring Spectrometer (GEMS)

Author

Kim, Jhoon, Jeong, Ukkyo, Ahn, Myoung-Hwan, Kim, Jae H., Park, Rokjin J., Lee, Hanlim, Song, Chul Han, Choi, Yong-Sang, Lee, Kwon-Ho, Yoo, Jung-Moon, Jeong, Myeong-Jae, Park, Seon Ki, Lee, Kwang-Mog, Song, Chang-Keun, Kim, Sang-Woo, Kim, Young Joon, Kim, Si-Wan, Kim, Mijin, Go, Sujung, Liu, Xiong, Chance, Kelly, Miller, Christopher Chan, Al-Saadi, Jay, Veihelmann, Ben, Bhartia, Pawan K., Torres, Omar, Abad, Gonzalo González, Haffner, David P., Ko, Dai Ho, Lee, Seung Hoon, Woo, Jung-Hun, Chong, Heesung, Park, Sang Seo, Nicks, Dennis, Choi, Won Jun, Moon, Kyung-Jung, Cho, Ara, Yoon, Jongmin, Kim, Sang-kyun, Hong, Hyunkee, Lee, Kyunghwa, Lee, Hana, Lee, Seoyoung, Choi, Myungje, Veefkind, Pepijn, Levelt, Pieternel F., Edwards, David P., Kang, Mina, Eo, Mijin, Bak, Juseon, Baek, Kanghyun, Kwon, Hyeong-Ahn, Yang, Jiwon, Park, Junsung, Han, Kyung Man, Kim, Bo-Ram, Shin, Hee-Woo, Choi, Haklim, Lee, Ebony, Chong, Jihyo, Cha, Yesol, Koo, Ja-Ho, Irie, Hitoshi, Hayashida, Sachiko, Kasai, Yasko, Kanaya, Yugo, Liu, Cheng, Lin, Jintai, Crawford, James H., Carmichael, Gregory R., Newchurch, Michael J., Lefer, Barry L., Herman, Jay R., Swap, Robert J., Lau, Alexis K. H., Kurosu, Thomas P., Jaross, Glen, Ahlers, Berit, Dobber, Marcel, McElroy, C. Thomas, and Choi, Yunsoo

Published
2020

11. Current potential of CH4 emission estimates using TROPOMI in the Middle East.

Author

Liu, Mengyao, A, Ronald van der, Weele, Michiel van, Bryan, Lotte, Eskes, Henk, Veefkind, Pepijn, Liu, Yongxue, Lin, Xiaojuan, Laat, Jos de, and Ding, Jieying

Subjects
EMISSION inventories, INFRARED imaging, DATABASES, METHANE, PETROLEUM industry
Abstract

An improved divergence method has been developed to estimate annual methane (CH4) emissions from TROPOspheric Monitoring Instrument (TROPOMI) observations. It has been applied to the period of 2018 to 2021 over the Middle East, where the orography is complicated, and the mean mixing ratio of methane (XCH4) might be affected by albedos or aerosols over some locations. To adapt to extreme changes of terrain over mountains or coasts, winds are used with their divergent part removed. A temporal filter is introduced to identify highly variable emissions and further exclude fake sources caused by retrieval artifacts. We compare our results to widely used bottom-up anthropogenic emission inventories: Emissions Database for Global Atmospheric Research (EDGAR), Community Emissions Data System (CEDS) and Global Fuel Exploitation Inventory (GFEI) over several regions representing various types of sources. The NOX emissions from EDGAR and Daily Emissions Constrained by Satellite Observations (DECSO), and the industrial heat sources identified by Visible Infrared Imaging Radiometer Suite (VIIRS) are further used to better understand our resulting methane emissions. Our results indicate possibly large underestimations of methane emissions in metropolises like Tehran (up to 50 %) and Isfahan (up to 70 %) in Iran. The derived annual methane emissions from oil/gas production near the Caspian Sea in Turkmenistan are comparable to GEFI but more than two times higher than EDGAR and CEDS in 2019. Large discrepancies of distribution of methane sources in Riyadh and its surrounding areas are found between EDGAR, CEDS, GFEI and our emissions. The methane emission from oil/gas production in the east to Riyadh seems to be largely overestimated by EDGAR and CEDS, while our estimates, and also GFEI and DECSO NOX indicate much lower emissions from industry activities. On the other hand, regions like Iran, Iraq, and Oman are dominated by sources from oil and gas exploitation that probably includes more irregular releases of methane, with the result that our estimates, that include only invariable sources, are lower than the bottom-up emission inventories. [ABSTRACT FROM AUTHOR]

Published
2024
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12. Tropical tropospheric ozone distribution and trends from in situ and satellite data.

Author

Gaudel, Audrey, Bourgeois, Ilann, Li, Meng, Chang, Kai-Lan, Ziemke, Jerald, Sauvage, Bastien, Stauffer, Ryan M., Thompson, Anne M., Kollonige, Debra E., Smith, Nadia, Hubert, Daan, Keppens, Arno, Cuesta, Juan, Heue, Klaus-Peter, Veefkind, Pepijn, Aikin, Kenneth, Peischl, Jeff, Thompson, Chelsea R., Ryerson, Thomas B., and Frost, Gregory J.

Subjects
TROPOSPHERIC ozone, GLOBAL radiation, OZONE, REMOTE sensing, OZONESONDES
Abstract

Tropical tropospheric ozone (TTO) is important for the global radiation budget because the longwave radiative effect of tropospheric ozone is higher in the tropics than mid-latitudes. In recent decades the TTO burden has increased, partly due to the ongoing shift of ozone precursor emissions from mid-latitude regions toward the equator. In this study, we assess the distribution and trends of TTO using ozone profiles measured by high quality in situ instruments from the IAGOS (In-Service Aircraft for a Global Observing System) commercial aircraft, the SHADOZ (Southern Hemisphere ADditional OZonesondes) network, and the ATom (Atmospheric Tomographic Mission) aircraft campaign, as well as six satellite records reporting tropical tropospheric column ozone (TTCO): TROPOMI, OMI, OMI/MLS, OMPS/MERRA2, CrIS, and IASI/GOME2. With greater availability of ozone profiles across the tropics we can now demonstrate that tropical India is among the most polluted regions (e.g., Western Africa, tropical South Atlantic, Southeast Asia, Malaysia/Indonesia) with present-day 95th percentile ozone values reaching 80 nmol mol−1 in the lower free troposphere, comparable to mid-latitude regions such as Northeast China/Korea. In situ observations show that TTO increased between 1994 and 2019, with the largest mid- and upper tropospheric increases above India, Southeast Asia and Malaysia/Indonesia (from 3.4 ± 0.8 to 6.8 ± 1.8 nmol mol−1 decade−1), reaching 11 ± 2.4 and 8 ± 0.8 nmol mol−1 decade−1 close to the surface (India and Malaysia/Indonesia, respectively). The longest continuous satellite records only span 2004−2019, but also show increasing ozone across the tropics when their full sampling is considered, with maximum trends over Southeast Asia of 2.31 ± 1.34 nmol mol−1 decade−1 (OMI) and 1.69 ± 0.89 nmol mol−1 decade−1 (OMI/MLS). In general, the sparsely sampled aircraft and ozonesonde records do not detect the 2004−2019 ozone increase, which could be due to the genuine trends on this timescale being masked by the additional uncertainty resulting from sparse sampling. The fact that the sign of the trends detected with satellite records changes above three IAGOS regions, when their sampling frequency is limited to that of the in situ observations, demonstrates the limitations of sparse in situ sampling strategies. This study exposes the need to maintain and develop high frequency continuous observations (in situ and remote sensing) above the tropical Pacific Ocean, the Indian Ocean, Western Africa and South Asia in order to estimate accurate and precise ozone trends for these regions. In contrast, Southeast Asia and Malaysia/Indonesia are regions with such strong increases of ozone that the current in situ sampling frequency is adequate to detect the trends on a relatively short 15-year time scale. [ABSTRACT FROM AUTHOR]

Published
2024
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13. Five years of Sentinel-5p TROPOMI operational ozone profiling and geophysical validation using ozonesonde and lidar ground-based networks.

Author

Keppens, Arno, Di Pede, Serena, Hubert, Daan, Lambert, Jean-Christopher, Veefkind, Pepijn, Sneep, Maarten, De Haan, Johan, ter Linden, Mark, Leblanc, Thierry, Compernolle, Steven, Verhoelst, Tijl, Granville, José, Nath, Oindrila, Fjæraa, Ann Mari, Boyd, Ian, Niemeijer, Sander, Van Malderen, Roeland, Smit, Herman G. J., Duflot, Valentin, and Godin-Beekmann, Sophie

Subjects
TROPOSPHERIC ozone, OZONE, LIDAR, ZENITH distance, DEGREES of freedom, STRATOSPHERE
Abstract

The Sentinel-5 Precursor (S5P) satellite operated by the European Space Agency (ESA) carries the TROPOspheric Monitoring Instrument (TROPOMI) on a Sun-synchronous low-Earth orbit since October 13, 2017. The S5P mission has acquired more than five years of TROPOMI nadir ozone profile data retrieved from the Level-0-to-1B processor version 2.0 and the Level-1B-to-2 Optimal Estimation based processor version 2.4.0. The latter is described in detail in this work, followed by the geophysical validation of the resulting ozone profiles for the period May 2018 to April 2023. Comparison of TROPOMI ozone profile data to co-located ozonesonde and lidar measurements used as references, concludes to a median agreement better than 5 to 10 % in the troposphere. The bias goes up to -15 % in the upper stratosphere (35-45 km) where it can exhibit vertical oscillations. The comparisons show a dispersion of about 30 % in the troposphere and 10 to 20 % in the upper troposphere to lower stratosphere (UTLS) and in the middle stratosphere, which is close to mission requirements. Chi-square tests of the observed differences confirm on average the validity of the ex-ante (prognostic) satellite and ground-based data uncertainty estimates in the middle stratosphere, above about 20 km. Around the tropopause and below, the mean chi-square value increases up to about four, meaning that the ex-ante TROPOMI uncertainty is underestimated. The information content of the ozone profile retrieval is characterised by about five to six vertical sub-columns of independent information and a vertical sensitivity nearly equal to unity at altitudes from about 20 to 50 km, decreasing rapidly at altitudes above and below. The barycentre of the retrieved information is usually close to the nominal retrieval altitude in the 20-50 km altitude range, with positive and negative offsets of up to 10 km below and above this range, respectively. The effective vertical resolution of the profile retrieval usually ranges within 10-15 km, with a minimum close to 7 km in the middle stratosphere. Increased sensitivity and higher effective vertical resolution are observed at higher solar zenith angle (SZA, above about 60°C), as can be expected, and correlate with higher retrieved ozone concentrations. The vertical sensitivity of the TROPOMI tropospheric ozone amount is found to depend on solar zenith angle, which translates into a seasonal and meridian dependence of its bias with respect to reference measurements. A similar although smaller effect can be seen for the viewing zenith angle (VZA). Additionally, the bias is negatively correlated with the surface albedo for the 6-12 km ozone subcolumn, despite the latter's apparently slightly positive correlation with the retrieval degrees of freedom in the signal. For the five years of TROPOMI ozone profile data that are available now, an overall positive drift is detected for the lowest three subcolumns (0-18 km), while a negative drift is observed for the two subcolumns above (18-32 km), resulting in a negligible vertically integrated drift. [ABSTRACT FROM AUTHOR]

Published
2024
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14. TROPOMI-derived NO2 emissions from copper/cobalt mining and other industrial activities in the Copperbelt (DRC and Zambia)

Author

Martinez-Alonso, Sara, primary, Veefkind, Pepijn, additional, Dix, Barbara Klara, additional, Gaubert, Benjamin, additional, Theys, Nicolas, additional, Granier, Claire, additional, Soulié, Antonin, additional, Darras, Sabine, additional, Eskes, Henk, additional, Tang, Wenfu, additional, Worden, Helen M., additional, Gouw, Joost A de, additional, and Levelt, Pieternel F, additional

Published
2023
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15. The Antarctic stratospheric Nitrogen Hole: Southern Hemisphere and Antarctic springtime total nitrogen dioxide and total ozone variability as observed in Sentinel-5p TROPOMI data.

Author

Laat, Adrianus de, Geffen, Jos van, Stammes, Piet, A, Ronald van der, Eskes, Henk, and Veefkind, Pepijn

Subjects
OZONE layer, NITROGEN dioxide, OZONE, OZONE layer depletion, PHASE space, NITROGEN
Abstract

Denitrification of the stratospheric vortex is a crucial process for the Antarctic Ozone Hole formation resulting in an analogous stratospheric "Nitrogen Hole". Here, 2018–2021 daily TROPOMI measurements are used for the first time for a detailed characterization of this Nitrogen Hole. Nitrogen dioxide total columns exhibit strong spatiotemporal and seasonal variations associated with both photochemistry as well as transport and mixing processes. Combined with total ozone column data two main regimes are identified: inner-vortex ozone and nitrogen dioxide depleted air and outer-vortex air enhanced in ozone and nitrogen dioxide. Within the vortex total ozone and total stratospheric nitrogen dioxide are strongly correlated which is much less evident outside of the vortex. Connecting both main regimes are what is defined here as "mixing lines", a third regime of coherent patterns in the total nitrogen dioxide column – total ozone column phase space. These mixing lines exist because of differences in three dimensional variations of nitrogen dioxide and ozone thereby providing information about vortex dynamics and cross-vortex edge mixing. On the other hand, interannual variability of nitrogen dioxide – total ozone characteristics are rather small except in 2019 when the vortex was unusually unstable. Overall, the results show that daily stratospheric nitrogen dioxide column satellite measurements provide an innovative means for characterizing and Polar stratospheric denitrification processes and vortex dynamics and potentially long term monitoring if the total nitrogen column data record is extended with past satellite observations. [ABSTRACT FROM AUTHOR]

Published
2023
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16. A TROPOMI- and GLM-Based Estimate of NOx Production by Lightning over the U.S.

Author

Allen, Dale, Pickering, Kenneth, Bucsela, Eric, Van Geffen, Jos, Eskes, Henk, Krotkov, Nickolay, Koshak, William, and Veefkind, Pepijn

Subjects
Meteorology And Climatology
Abstract

Lightning produces NO because the extreme temperatures (>20000 K) in lightning channels dissociate molecular O2 and molecular N2, which then combine to form NOx which quickly reacts with O3 to form NO2. Lightning is responsible for 10-15% of NOx emissions globally. This is 2 – 8 Tg N a-1 [Schumann and Huntrieser, 2007] or 100 to 400 mol per flash. Much of the uncertainty stems from limited knowledge of lightning NOx production per flash (LNOx PE) or per unit flash length. Most LNOx is injected into mid- and upper-troposphere where away from deep convection its lifetime is longer relative to lower troposphere NOx. NOx in this region enhances the concentrations of upper tropospheric NOy, OH, and O3 and contributes to positive radiative forcing by O3 and negative forcing by CH4. We have previously used OMI NO2 to obtain estimates of LNOx production per flash over the Gulf of Mexico (Pickering et al., 2016, JGR), in convective events during NASA’s TC4 field program (Bucsela et al., 2010, JGR), and over broad regions of the tropics (Allen et al., 2019, JGR) and midlatitudes (Bucsela et al., 2019, JGR). In the latter studies, we obtained PE values of 170 ± 100 mol flash and 180 ± 100 mol flash, respectively.

Published
2019

17. Emissions from Mining-related Activities in Africa using TROPOMI Satellite Observations

Author

Martínez-Alonso, Sara, primary, Veefkind, Pepijn, additional, Dix, Barbara, additional, Gaubert, Benjamin, additional, Granier, Claire, additional, Soulié, Antonin, additional, Darras, Sabine, additional, Theys, Nicolas, additional, Emmons, Louisa, additional, Eskes, Henk, additional, Tang, Wenfu, additional, Worden, Helen, additional, deGouw, Joost, additional, and Levelt, Pieternel, additional

Published
2023
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25. Absorption cross-sections of ozone in the ultraviolet and visible spectral regions: Status report 2015

Author

Orphal, Johannes, Staehelin, Johannes, Tamminen, Johanna, Braathen, Geir, De Backer, Marie-Renée, Bais, Alkiviadis, Balis, Dimitris, Barbe, Alain, Bhartia, Pawan K., Birk, Manfred, Burkholder, James B., Chance, Kelly, von Clarmann, Thomas, Cox, Anthony, Degenstein, Doug, Evans, Robert, Flaud, Jean-Marie, Flittner, David, Godin-Beekmann, Sophie, Gorshelev, Viktor, Gratien, Aline, Hare, Edward, Janssen, Christof, Kyrölä, Erkki, McElroy, Thomas, McPeters, Richard, Pastel, Maud, Petersen, Michael, Petropavlovskikh, Irina, Picquet-Varrault, Benedicte, Pitts, Michael, Labow, Gordon, Rotger-Languereau, Maud, Leblanc, Thierry, Lerot, Christophe, Liu, Xiong, Moussay, Philippe, Redondas, Alberto, Van Roozendael, Michel, Sander, Stanley P., Schneider, Matthias, Serdyuchenko, Anna, Veefkind, Pepijn, Viallon, Joële, Viatte, Camille, Wagner, Georg, Weber, Mark, Wielgosz, Robert I., and Zehner, Claus

Published
2016
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27. Intercomparison of Sentinel-5P TROPOMI cloud products for tropospheric trace gas retrievals

Author

Latsch, Miriam, primary, Richter, Andreas, additional, Eskes, Henk, additional, Sneep, Maarten, additional, Wang, Ping, additional, Veefkind, Pepijn, additional, Lutz, Ronny, additional, Loyola, Diego, additional, Argyrouli, Athina, additional, Valks, Pieter, additional, Wagner, Thomas, additional, Sihler, Holger, additional, van Roozendael, Michel, additional, Theys, Nicolas, additional, Yu, Huan, additional, Siddans, Richard, additional, and Burrows, John P., additional

Published
2022
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28. Retrieval of Aerosol Properties

Author

de Leeuw, Gerrit, Kinne, Stefan, Léon, Jean-Francois, Pelon, Jacques, Rosenfeld, Daniel, Schaap, Martijn, Veefkind, Pepijn J., Veihelmann, Ben, Winker, David M., von Hoyningen-Huene, Wolfgang, Burrows, John P., editor, Borrell, Peter, editor, and Platt, Ulrich, editor

Published
2011
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29. Tropospheric and stratospheric ozone profiles during the 2019 TROpomi vaLIdation eXperiment (TROLIX-19)

Author

Sullivan, John T., primary, Apituley, Arnoud, additional, Mettig, Nora, additional, Kreher, Karin, additional, Knowland, K. Emma, additional, Allaart, Marc, additional, Piters, Ankie, additional, Van Roozendael, Michel, additional, Veefkind, Pepijn, additional, Ziemke, Jerry R., additional, Kramarova, Natalya, additional, Weber, Mark, additional, Rozanov, Alexei, additional, Twigg, Laurence, additional, Sumnicht, Grant, additional, and McGee, Thomas J., additional

Published
2022
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31. Validation of the TROPOMI/S5P Aerosol Layer Height using EARLINET lidars

Author

Michailidis, Konstantinos, primary, Koukouli, Maria-Elissavet, additional, Balis, Dimitris, additional, Veefkind, Pepijn, additional, de Graaf, Martin, additional, Mona, Lucia, additional, Papagianopoulos, Nikolaos, additional, Pappalardo, Gesolmina, additional, Tsikoudi, Ioanna, additional, Amiridis, Vassilis, additional, Marinou, Eleni, additional, Gialitaki, Anna, additional, Mamouri, Rodanthi-Elissavet, additional, Nisantzi, Argyro, additional, Bortoli, Daniele, additional, João Costa, Maria, additional, Salgueiro, Vanda, additional, Papayannis, Alexandros, additional, Mylonaki, Maria, additional, Alados-Arboledas, Lucas, additional, Romano, Salvatore, additional, Perrone, Maria Rita, additional, and Baars, Holger, additional

Published
2022
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32. Supplementary material to "Intercomparison of Sentinel-5P TROPOMI cloud products for tropospheric trace gas retrievals"

Author

Latsch, Miriam, primary, Richter, Andreas, additional, Eskes, Henk, additional, Sneep, Maarten, additional, Wang, Ping, additional, Veefkind, Pepijn, additional, Lutz, Ronny, additional, Loyola, Diego, additional, Argyrouli, Athina, additional, Valks, Pieter, additional, Wagner, Thomas, additional, Sihler, Holger, additional, van Roozendael, Michel, additional, Theys, Nicolas, additional, Yu, Huan, additional, Siddans, Richard, additional, and Burrows, John P., additional

Published
2022
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34. Ozone Monitoring Instrument (OMI) collection 4: establishing a 17-year-long series of detrended level-1b data

Author

Kleipool, Quintus, primary, Rozemeijer, Nico, additional, van Hoek, Mirna, additional, Leloux, Jonatan, additional, Loots, Erwin, additional, Ludewig, Antje, additional, van der Plas, Emiel, additional, Adrichem, Daley, additional, Harel, Raoul, additional, Spronk, Simon, additional, ter Linden, Mark, additional, Jaross, Glen, additional, Haffner, David, additional, Veefkind, Pepijn, additional, and Levelt, Pieternel F., additional

Published
2022
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35. Combined UV and IR ozone profile retrieval from TROPOMI and CrIS measurements

Author

Mettig, Nora, primary, Weber, Mark, additional, Rozanov, Alexei, additional, Burrows, John P., additional, Veefkind, Pepijn, additional, Thompson, Anne M., additional, Stauffer, Ryan M., additional, Leblanc, Thierry, additional, Ancellet, Gerard, additional, Newchurch, Michael J., additional, Kuang, Shi, additional, Kivi, Rigel, additional, Tully, Matthew B., additional, Van Malderen, Roeland, additional, Piters, Ankie, additional, Kois, Bogumil, additional, Stübi, René, additional, and Skrivankova, Pavla, additional

Published
2022
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36. Measurement Report: Tropospheric and Stratospheric Ozone Profiles during the 2019 TROpomi vaLIdation eXperiment (TROLIX-19)

Author

Sullivan, John, primary, Apituley, Arnoud, additional, Mettig, Nora, additional, Kreher, Karin, additional, Knowland, K. Emma, additional, Allart, Marc, additional, Piters, Ankie, additional, Van Roozendael, Michel, additional, Veefkind, Pepijn, additional, Ziemke, Jerry, additional, Kramarova, Natalya, additional, Weber, Mark, additional, Rozanov, Alexei, additional, Twigg, Laurence, additional, Sumnicht, Grant, additional, and McGee, Thomas, additional

Published
2022
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40. Supplementary material to "OMI Collection 4: establishing a 17-year long series of detrended L1b data"

Author

Kleipool, Quintus, primary, Rozemeijer, Nico, additional, van Hoek, Mirna, additional, Leloux, Jonatan, additional, Loots, Erwin, additional, Ludewig, Antje, additional, van der Plas, Emiel, additional, Adrichem, Daley, additional, Harel, Raoul, additional, Spronk, Simon, additional, ter Linden, Mark, additional, Jaross, Glen, additional, Haffner, David, additional, Veefkind, Pepijn, additional, and Levelt, Pieternel, additional

Published
2022
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41. OMI Collection 4: establishing a 17-year long series of detrended L1b data

Author

Kleipool, Quintus, primary, Rozemeijer, Nico, additional, van Hoek, Mirna, additional, Leloux, Jonatan, additional, Loots, Erwin, additional, Ludewig, Antje, additional, van der Plas, Emiel, additional, Adrichem, Daley, additional, Harel, Raoul, additional, Spronk, Simon, additional, ter Linden, Mark, additional, Jaross, Glen, additional, Haffner, David, additional, Veefkind, Pepijn, additional, and Levelt, Pieternel, additional

Published
2022
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42. Supplementary material to "Combined UV and IR ozone profile retrieval from TROPOMI and CrIS measurements"

Author

Mettig, Nora, primary, Weber, Mark, additional, Rozanov, Alexei, additional, Burrows, John P., additional, Veefkind, Pepijn, additional, Smith, Nadia, additional, Thompson, Anne M., additional, Stauffer, Ryan M., additional, Leblanc, Thierry, additional, Kivi, Rigel, additional, Tully, Matthew B., additional, Van Malderen, Roeland, additional, Piters, Ankie, additional, Kois, Bogumil, additional, Stübi, René, additional, and Skrivankova, Pavla, additional

Published
2021
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43. Combined UV and IR ozone profile retrieval from TROPOMI and CrIS measurements

Author

Mettig, Nora, primary, Weber, Mark, additional, Rozanov, Alexei, additional, Burrows, John P., additional, Veefkind, Pepijn, additional, Smith, Nadia, additional, Thompson, Anne M., additional, Stauffer, Ryan M., additional, Leblanc, Thierry, additional, Kivi, Rigel, additional, Tully, Matthew B., additional, Van Malderen, Roeland, additional, Piters, Ankie, additional, Kois, Bogumil, additional, Stübi, René, additional, and Skrivankova, Pavla, additional

Published
2021
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44. A New Divergence Method to Quantify Methane Emissions Using Observations of Sentinel‐5P TROPOMI

Author

Liu, Mengyao, primary, van der A, Ronald, additional, van Weele, Michiel, additional, Eskes, Henk, additional, Lu, Xiao, additional, Veefkind, Pepijn, additional, de Laat, Jos, additional, Kong, Hao, additional, Wang, Jingxu, additional, Sun, Jiyunting, additional, Ding, Jieying, additional, Zhao, Yuanhong, additional, and Weng, Hongjian, additional

Published
2021
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45. Ozone profile retrieval from nadir TROPOMI measurements in the UV range

Author

Mettig, Nora, primary, Weber, Mark, additional, Rozanov, Alexei, additional, Arosio, Carlo, additional, Burrows, John P., additional, Veefkind, Pepijn, additional, Thompson, Anne M., additional, Querel, Richard, additional, Leblanc, Thierry, additional, Godin-Beekmann, Sophie, additional, Kivi, Rigel, additional, and Tully, Matthew B., additional

Published
2021
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46. CHAPS: a sustainable approach to targeted air pollution observation from small satellites

Author

Swartz, William H., primary, Krotkov, Nickolay, additional, Lamsal, Lok, additional, Otter, Gerard, additional, van Kempen, Floris, additional, Boldt, John, additional, Morgan, Frank, additional, van der Laan, Ludger, additional, Zimbeck, Walter, additional, Storck, Steven, additional, Post, Zachary, additional, Janz, Scott, additional, Kowalewski, Matthew, additional, Li, Can, additional, Veefkind, Pepijn, additional, and Levelt, Pieternel, additional

Published
2021
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47. Assessment of the TROPOMI tropospheric NO2 product based on airborne APEX observations

Author

Tack, Frederik, Merlaud, Alexis, Iordache, Marian-Daniel, Pinardi, Gaia, Dimitropoulou, Ermioni, Eskes, Henk, Bomans, Bart, Veefkind, Pepijn, and Roozendael, Michel

Subjects
TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES, lcsh:TA715-787, lcsh:Earthwork. Foundations, lcsh:TA170-171, lcsh:Environmental engineering
Abstract

Sentinel-5 Precursor (S-5P), launched in October 2017, carrying the TROPOspheric Monitoring Instrument (TROPOMI) nadir-viewing spectrometer, is the first mission of the Copernicus Programme dedicated to the monitoring of air quality, climate, and ozone. In the presented study, the TROPOMI tropospheric nitrogen dioxide (NO2) level-2 (L2) product (OFFL v1.03.01; 3.5 km × 7 km at nadir observations) has been validated over strongly polluted urban regions by comparison with coincident high-resolution Airborne Prism EXperiment (APEX) remote sensing observations (∼ 75 m × 120 m). Satellite products can be optimally assessed based on (APEX) airborne remote sensing observations, as a large amount of satellite pixels can be fully mapped at high accuracy and in a relatively short time interval, reducing the impact of spatiotemporal mismatches. In the framework of the S-5P validation campaign over Belgium (S5PVAL-BE), the APEX imaging spectrometer has been deployed during four mapping flights (26–29 June 2019) over the two largest urban regions in Belgium, i.e. Brussels and Antwerp, in order to map the horizontal distribution of tropospheric NO2. For each flight, 10 to 20 TROPOMI pixels were fully covered by approximately 2700 to 4000 APEX measurements within each TROPOMI pixel. The TROPOMI and APEX NO2 vertical column density (VCD) retrieval schemes are similar in concept. Overall, for the ensemble of the four flights, the standard TROPOMI NO2 VCD product is well correlated (R = 0.92) but biased negatively by −1.2 ± 1.2 × 1015 molec cm−2 or −14 ± 12 %, on average, with respect to coincident APEX NO2 retrievals. When replacing the coarse 1∘ × 1∘ the massively parallel (MP) version of the Tracer Model version 5 (TM5) a priori NO2 profiles by NO2 profile shapes from the Copernicus Atmospheric Monitoring Service (CAMS) regional chemistry transport model (CTM) ensemble at 0.1∘ × 0.1∘, R is 0.94 and the slope increases from 0.82 to 0.93. The bias is reduced to −0.1 ± 1.0 × 1015 molec cm−2 or −1.0 ± 12 %. The absolute difference is on average 1.3 × 1015 molec cm−2 (16 %) and 0.7 × 1015 molec cm−2 (9 %), when comparing APEX NO2 VCDs with TM5-MP-based and CAMS-based NO2 VCDs, respectively. Both sets of retrievals are well within the mission accuracy requirement of a maximum bias of 25 %–50 % for the TROPOMI tropospheric NO2 product for all individual compared pixels. Additionally, the APEX data set allows the study of TROPOMI subpixel variability and impact of signal smoothing due to its finite satellite pixel size, typically coarser than fine-scale gradients in the urban NO2 field. For a case study in the Antwerp region, the current TROPOMI data underestimate localized enhancements and overestimate background values by approximately 1–2 × 1015 molec cm−2 (10 %–20 %).

Published
2021

48. Ground-based validation of the Copernicus Sentinel-5p TROPOMI NO2 measurements with the NDACC ZSL-DOAS, MAX-DOAS and Pandonia global networks

Author

Verhoelst, Tiji, Pinardi, Gala, Eskes, Henk J., Fjæraa, Ann Mari, Boersma, Klaas Folkert, Levelt, Pieternel F., Navarro-Comas, Monica, Piters, Ankie J. M., Sinyakov, Valery P., Strong, Kimberley, Veefkind, Pepijn J., Yela-González, Margarita, Verhoelst, Tijl, Compernolle, Steven, Pinardi, Gaia, Lambert, Jean-Christopher, Eskes, Henk, Eichmann, Kai-Uwe, Fjaeraa, Ann, Granville, José, Niemeijer, Sander, Cede, Alexander, Tiefengraber, Martin, Hendrick, François, Pazmino, Andrea, Bais, Alkiviadis, Bazureau, Ariane, Folkert Boersma, K, Bognar, Kristof, Dehn, Angelika, Donner, Sebastian, Elokhov, Aleksandr, Gebetsberger, Manuel, Goutail, Florence, Grutter de la Mora, Michel, Gruzdev, Aleksandr, Gratsea, Myrto, Hansen, Georg, Irie, Hitoshi, Jepsen, Nis, Kanaya, Yugo, Karagkiozidis, Dimitris, Kivi, Rigel, Kreher, Karin, Levelt, Pieternel, Liu, Cheng, Müller, Moritz, Navarro Comas, Monica, Piters, Ankie, Pommereau, Jean-Pierre, Portafaix, Thierry, Prados-Roman, Cristina, Puentedura, Olga, Querel, Richard, Remmers, Julia, Richter, Andreas, Rimmer, John, Rivera Cárdenas, Claudia, Saavedra De Miguel, Lidia, Sinyakov, Valery, Stremme, Wolfgang, Strong, Kimberly, Van Roozendaël, Michel, Pepijn Veefkind, J, Wagner, Thomas, Wittrock, Folkard, Yela González, Margarita, Zehner, Claus, Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Royal Netherlands Meteorological Institute (KNMI), Norsk Institutt for Luftforskning (NILU), Meteorology and Air Quality Group, Wageningen University and Research [Wageningen] (WUR), Delft University of Technology (TU Delft), Instituto Nacional de Técnica Aeroespacial (INTA), Kyrgyz National University of Jusup Balasagyn, Department of Physics [Toronto], University of Toronto, BK Scientific GmbH, Institut für Umweltphysik [Bremen] (IUP), Universität Bremen, Science [&] Technology Corporation [Delft] (S [&] T), NASA Goddard Space Flight Center (GSFC), Institute of Meteorology and Geophysics [Innsbruck], University of Innsbruck, STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratory of Atmospheric Physics [Thessaloniki], Aristotle University of Thessaloniki, European Space Research Institute (ESRIN), European Space Agency (ESA), Max-Planck-Institut für Chemie (MPIC), Max-Planck-Gesellschaft, A.M.Obukhov Institute of Atmospheric Physics (IAP), Russian Academy of Sciences [Moscow] (RAS), Centro de Ciencias de la Atmosfera [Mexico], Universidad Nacional Autónoma de México (UNAM), National Observatory of Athens (NOA), Center for Environmental Remote Sensing [Chiba] (CEReS), Chiba University, Danish Meteorological Institute (DMI), Research Institute for Global Change (RIGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Space and Earth Observation Centre [Sodankylä], Finnish Meteorological Institute (FMI), Department of Precision Machinery and Precision Instrumentation [Hefei], University of Science and Technology of China [Hefei] (USTC), Laboratoire de l'Atmosphère et des Cyclones (LACy), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Météo France, National Institute of Water and Atmospheric Research [Lauder] (NIWA), University of Manchester [Manchester], Institute of Environmental Physics [Bremen] (IUP), and University of Bremen

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere
Abstract

International audience; This paper reports on consolidated ground-based validation results of the atmospheric NO2 data produced operationally since April 2018 by the TROPOMI instrument on board of the ESA/EU Copernicus Sentinel-5 Precursor (S5p) satellite. Tropospheric, stratospheric, and total NO2 column data from S5p are compared to correlative measurements collected from, respectively, 19 Multi-Axis DOAS (MAX-DOAS), 26 NDACC Zenith-Scattered-Light DOAS (ZSL-DOAS), and 25 PGN/Pandora instruments distributed globally. The validation methodology gives special care to minimizing mismatch errors due to imperfect spatio-temporal co-location of the satellite and correlative data, e.g., by using tailored observation operators to account for differences in smoothing and in sampling of atmospheric structures and variability, and photochemical modelling to reduce diurnal cycle effects. Compared to the ground-based measurements, S5p data show, on an average: (i) a negative bias for the tropospheric column data, of typically −23 to −37 % in clean to slightly polluted conditions, but reaching values as high as −51 % over highly polluted areas; (ii) a slight negative bias for the stratospheric column data, of about −0.2 Pmolec/cm2, i.e. approx. −2 % in summer to −15 % in winter; and (iii) a bias ranging from zero to −50 % for the total column data, found to depend on the amplitude of the total NO2 column, with small to slightly positive bias values for columns below 6 Pmolec/cm2 and negative values above. The dispersion between S5p and correlative measurements contains mostly random components, which remain within mission requirements for the stratospheric column data (0.5 Pmolec/cm2), but exceed those for the tropospheric column data (0.7 Pmolec/cm2). While a part of the biases and dispersion may be due to representativeness differences, it is known that errors in the S5p tropospheric columns exist due to shortcomings in the (horizontally coarse) a-priori profile representation in the TM5-MP chemistry transport model used in the S5p retrieval, and to a lesser extent, to the treatment of cloud effects. Although considerable differences (up to 2 Pmolec/cm2 and more) are observed at single ground-pixel level, the near-real-time (NRTI) and off-line (OFFL) versions of the S5p NO2 operational data processor provide similar NO2 column values and validation results when globally averaged, with the NRTI values being on average 0.79 % larger than the OFFL values.

Published
2021

49. Unprecedented Arctic ozone loss in 2011

Author

Manney, Gloria L., Santee, Michelle L., Rex, Markus, Livesey, Nathaniel J., Pitts, Michael C., Veefkind, Pepijn, Nash, Eric R., Wohltmann, Ingo, Lehmann, Ralph, Froidevaux, Lucien, Poole, Lamont R., Schoeberl, Mark R., Haffner, David P., Davies, Jonathan, Dorokhov, Valery, Gernandt, Hartwig, Johnson, Bryan, Kivi, Rigel, Kyro, Esko, Larsen, Niels, Levelt, Pieternel F., Makshtas, Alexander, McElroy, C. Thomas, Nakajima, Hideaki, Parrondo, Maria Concepcion, Tarasick, David W., von der Gathen, Peter, Walker, Kaley A., and Zinoviev, Nikita S.

Subjects
Atmosphere -- Research, Earth -- Atmosphere, Ozone layer depletion -- Environmental aspects -- Research, Air pollution -- Environmental aspects -- Research, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Chemical ozone destruction occurs over both polar regions in local winter-spring. In the Antarctic, essentially complete removal of lower-stratospheric ozone currently results in an ozone hole every year, whereas in the Arctic, ozone loss is highly variable and has until now been much more limited. Here we demonstrate that chemical ozone destruction over the Arctic in early 2011 was--for the first time in the observational record--comparable to that in the Antarctic ozone hole. Unusually long-lasting cold conditions in the Arctic lower stratosphere led to persistent enhancement in ozone-destroying forms of chlorine and to unprecedented ozone loss, which exceeded 80 per cent over 18-20 kilometres altitude. Our results show that Arctic ozone holes are possible even with temperatures much milder than those in the Antarctic. We cannot at present predict when such severe Arctic ozone depletion may be matched or exceeded., Since the emergence of the Antarctic 'ozone hole' in the 1980s (1) and elucidation of the chemical mechanisms (2-5) and meteorological conditions (6) involved in its formation, the likelihood of [...]

Published
2011
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50. Supplementary material to "Ozone Profile Retrieval from nadir TROPOMI measurements in the UV range"

Author

Mettig, Nora, primary, Weber, Mark, additional, Rozanov, Alexei, additional, Arosio, Carlo, additional, Burrows, John P., additional, Veefkind, Pepijn, additional, Thompson, Anne M., additional, Querel, Richard, additional, Leblanc, Thierry, additional, Godin-Beekmann, Sophie, additional, Kivi, Rigel, additional, and Tully, Matthew B., additional

Published
2021
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