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Comparative assessment of TROPOMI and OMI formaldehyde observations and validation against MAX-DOAS network column measurements

De Smedt, Isabelle and Pinardi, Gaia and Vigouroux, Corinne and Compernolle, Steven and Bais, Alkiviadis F. and Benavent, N. and Boersma, F. and Chan, Ka Lok and Donner, Sebastian and Eichmann, K.U. and Hedelt, Pascal and Hendrick, Francoise and Irie, Hitoshi and Kumar, Vinod and Lambert, Jean-Christopher and Langerock, Bavo and Lerot, Christophe and Liu, Cheng and Loyola, Diego and Piters, Ankie and Richter, Andreas and Rivera Cardenas, Claudia and Romahn, Fabian and Ryan, Robert George and Sinha, Vinayak and Theys, Nicolas and Vlietinck, Jonas and Wagner, Thomas and Wang, Ting and Yu, Huan and Van Roozendael, M. (2021) Comparative assessment of TROPOMI and OMI formaldehyde observations and validation against MAX-DOAS network column measurements. Atmospheric Chemistry and Physics (ACP), 21 (16), pp. 12561-12593. Copernicus Publications. doi: 10.5194/acp-21-12561-2021. ISSN 1680-7316.

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Official URL: https://acp.copernicus.org/articles/21/12561/2021/


The TROPOspheric Monitoring Instrument (TROPOMI), launched in October 2017 on board the Sentinel-5 Precursor (S5P) satellite, monitors the composition of the Earth's atmosphere at an unprecedented horizontal resolution as fine as 3.5 × 5.5 km2. This paper assesses the performances of the TROPOMI formaldehyde (HCHO) operational product compared to its predecessor, the OMI (Ozone Monitoring Instrument) HCHO QA4ECV product, at different spatial and temporal scales. The parallel development of the two algorithms favoured the consistency of the products, which facilitates the production of long-term combined time series. The main difference between the two satellite products is related to the use of different cloud algorithms, leading to a positive bias of OMI compared to TROPOMI of up to 30 % in tropical regions. We show that after switching off the explicit correction for cloud effects, the two datasets come into an excellent agreement. For medium to large HCHO vertical columns (larger than 5 × 1015 molec. cm−2) the median bias between OMI and TROPOMI HCHO columns is not larger than 10 % (< 0.4 × 1015 molec. cm−2). For lower columns, OMI observations present a remaining positive bias of about 20 % (< 0.8 × 1015 molec. cm−2) compared to TROPOMI in midlatitude regions. Here, we also use a global network of 18 MAX-DOAS (multi-axis differential optical absorption spectroscopy) instruments to validate both satellite sensors for a large range of HCHO columns. This work complements the study by Vigouroux et al. (2020), where a global FTIR (Fourier transform infrared) network is used to validate the TROPOMI HCHO operational product. Consistent with the FTIR validation study, we find that for elevated HCHO columns, TROPOMI data are systematically low (−25 % for HCHO columns larger than 8 × 1015 molec. cm−2), while no significant bias is found for medium-range column values. We further show that OMI and TROPOMI data present equivalent biases for large HCHO levels. However, TROPOMI significantly improves the precision of the HCHO observations at short temporal scales and for low HCHO columns. We show that compared to OMI, the precision of the TROPOMI HCHO columns is improved by 25 % for individual pixels and by up to a factor of 3 when considering daily averages in 20 km radius circles. The validation precision obtained with daily TROPOMI observations is comparable to the one obtained with monthly OMI observations. To illustrate the improved performances of TROPOMI in capturing weak HCHO signals, we present clear detection of HCHO column enhancements related to shipping emissions in the Indian Ocean. This is achieved by averaging data over a much shorter period (3 months) than required with previous sensors (5 years) and opens new perspectives to study shipping emissions of VOCs (volatile organic compounds) and related atmospheric chemical interactions.

Item URL in elib:https://elib.dlr.de/143579/
Document Type:Article
Title:Comparative assessment of TROPOMI and OMI formaldehyde observations and validation against MAX-DOAS network column measurements
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
De Smedt, IsabelleBelgian Institute for Space Aeronomy, Brussels, Belgiumhttps://orcid.org/0000-0002-3541-7725UNSPECIFIED
Pinardi, GaiaBelgian Institute for Space Aeronomy, Brussels, Belgiumhttps://orcid.org/0000-0001-5428-916XUNSPECIFIED
Vigouroux, CorinneBelgian Institute for Space Aeronomy, Brussels, BelgiumUNSPECIFIEDUNSPECIFIED
Compernolle, StevenBelgian Institute for Space Aeronomy, Brussels, Belgiumhttps://orcid.org/0000-0003-0872-0961UNSPECIFIED
Bais, Alkiviadis F.Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greecehttps://orcid.org/0000-0003-3899-2001UNSPECIFIED
Benavent, N.Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano (CSIC), Madrid, SpainUNSPECIFIEDUNSPECIFIED
Boersma, F.Royal Netherlands Meteorological Institute, KNMI, De Bilt, the NetherlandsUNSPECIFIEDUNSPECIFIED
Eichmann, K.U.Institut für Umweltphysik,UniversitätBremen,Bremen,GermanyUNSPECIFIEDUNSPECIFIED
Hedelt, PascalUNSPECIFIEDhttps://orcid.org/0000-0002-1752-0040UNSPECIFIED
Hendrick, FrancoiseBelgian Institute for Space Aeronomy, Brussels, BelgiumUNSPECIFIEDUNSPECIFIED
Irie, HitoshiCenter for Environmental Remote Sensing, Chiba University (Chiba U), Chiba, JapanUNSPECIFIEDUNSPECIFIED
Kumar, VinodMax Planck Institute for Chemistry, Mainz, GermanyUNSPECIFIEDUNSPECIFIED
Lambert, Jean-ChristopherRoyal Belgian Institute for Space Aeronomy (BIRA)UNSPECIFIEDUNSPECIFIED
Langerock, BavoBelgian Institute for Space Aeronomy, BIRA-IASB, Ringlaan 3, 1080 Brussels, BelgiumUNSPECIFIEDUNSPECIFIED
Lerot, ChristopheBelgian Institute for Space Aeronomy (BIRA-IASB), Brussels, BelgiumUNSPECIFIEDUNSPECIFIED
Liu, ChengSchool of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, Chinahttps://orcid.org/0000-0002-3759-9219UNSPECIFIED
Loyola, DiegoUNSPECIFIEDhttps://orcid.org/0000-0002-8547-9350UNSPECIFIED
Piters, AnkieRoyal Netherlands Meteorological Institute (KNMI), De Bilt, the NetherlandsUNSPECIFIEDUNSPECIFIED
Richter, AndreasInstitute of Environmental Physics, University of Bremen (IUP-B), Bremen, Germanyhttps://orcid.org/0000-0003-3877-8275UNSPECIFIED
Rivera Cardenas, ClaudiaCentro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexicohttps://orcid.org/0000-0002-8617-265XUNSPECIFIED
Ryan, Robert GeorgeSchool of Earth Sciences, The University of Melbourne, Melbourne, AustraliaUNSPECIFIEDUNSPECIFIED
Sinha, VinayakDepartment of Earth and Environmental Sciences, Indian Institute of Science Education and Research (IISER), Mohali, Indiahttps://orcid.org/0000-0002-5508-0779UNSPECIFIED
Theys, NicolasBelgian Institute for Space Aeronomy, Brussels, BelgiumUNSPECIFIEDUNSPECIFIED
Vlietinck, JonasBelgian Institute for Space Aeronomy, Brussels, BelgiumUNSPECIFIEDUNSPECIFIED
Wagner, ThomasMax Planck Institute for Chemistry, MainzUNSPECIFIEDUNSPECIFIED
Wang, TingInstitute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, ChinaUNSPECIFIEDUNSPECIFIED
Yu, HuanBelgian Institute for Space Aeronomy, Brussels, BelgiumUNSPECIFIEDUNSPECIFIED
Van Roozendael, M.BIRA-IASB – Royal Belgian Institute for Space Aeronomy, Brussels, BelgiumUNSPECIFIEDUNSPECIFIED
Journal or Publication Title:Atmospheric Chemistry and Physics (ACP)
Refereed publication:Yes
Open Access:Yes
Gold Open Access:Yes
In ISI Web of Science:Yes
Page Range:pp. 12561-12593
Publisher:Copernicus Publications
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Earth Observation
DLR - Research area:Raumfahrt
DLR - Program:R EO - Earth Observation
DLR - Research theme (Project):R - Remote Sensing and Geo Research, R - Spectroscopic methods of the atmosphere
Location: Oberpfaffenhofen
Institutes and Institutions:Remote Sensing Technology Institute > Atmospheric Processors
Deposited By: Hedelt, Pascal
Deposited On:23 Aug 2021 11:22
Last Modified:24 Aug 2021 10:01

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