eprintid: 10206253
rev_number: 8
eprint_status: archive
userid: 699
dir: disk0/10/20/62/53
datestamp: 2025-03-19 12:33:33
lastmod: 2025-03-19 12:33:33
status_changed: 2025-03-19 12:33:33
type: article
metadata_visibility: show
sword_depositor: 699
creators_name: Opacka, Beata
creators_name: Stavrakou, Trissevgeni
creators_name: Müller, Jean-François
creators_name: De Smedt, Isabelle
creators_name: van Geffen, Jos
creators_name: Marais, Eloise A
creators_name: Horner, Rebekah P
creators_name: Millet, Dylan B
creators_name: Wells, Kelly C
creators_name: Guenther, Alex B
title: Natural emissions of VOC and NOx over Africa
constrained by TROPOMI HCHO and NO2 data using the
MAGRITTEv1.1 model
ispublished: pub
divisions: UCL
divisions: B03
divisions: C03
divisions: F26
note: © Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
abstract: Abstract. Natural emissions (vegetation, soil, and lightning) are the dominant sources of non-methane biogenic volatile organic compounds (BVOCs) and nitrogen oxides (NOx≡ NO + NO2) released into the atmosphere over Africa. BVOCs and NOx interact with each other and strongly impact their own chemical lifetimes and degradation pathways, in particular through their influence on hydroxyl radical levels. To account for this intricate interplay between NOx and VOCs, we design and apply a novel inversion setup aiming at simultaneous optimization of monthly VOC and NOx emissions in 2019 in a regional chemistry-transport model, based on Tropospheric Ozone Monitoring Instrument (TROPOMI) HCHO and NO2 satellite observations. The TROPOMI-based inversions suggest substantial underestimations of natural NOx and VOC emissions used as a priori in the model. The annual flux over Africa increases from 125 to 165 Tg yr−1 for isoprene, from 1.9 to 2.4 TgN yr−1 for soil NO emissions, and from 0.5 to 2.0 TgN yr−1 for lightning NO emissions. Despite the NOx emission increase, evaluation against in situ NO2 measurements at seven rural sites in western Africa displays significant model underestimations after optimization. The large increases in lightning emissions are supported by comparisons with TROPOMI cloud-sliced upper-tropospheric NO2 volume mixing ratios, which remain underestimated by the model even after optimization. Our study strongly supports the application of a bias correction to the TROPOMI HCHO data and the use of a two-species constraint (vs. single-species inversion), based on comparisons with isoprene columns retrieved from the Cross-track Infrared Sensor (CrIS).
date: 2025-03-10
date_type: published
publisher: Copernicus GmbH
official_url: https://doi.org/10.5194/acp-25-2863-2025
oa_status: green
full_text_type: pub
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 2368989
doi: 10.5194/acp-25-2863-2025
lyricists_name: Marais, Eloise
lyricists_id: EAMAR45
actors_name: Marais, Eloise
actors_id: EAMAR45
actors_role: owner
full_text_status: public
publication: Atmospheric Chemistry and Physics
volume: 25
number: 5
pagerange: 2863-2894
issn: 1680-7324
citation:        Opacka, Beata;    Stavrakou, Trissevgeni;    Müller, Jean-François;    De Smedt, Isabelle;    van Geffen, Jos;    Marais, Eloise A;    Horner, Rebekah P;             ... Guenther, Alex B; + view all <#>        Opacka, Beata;  Stavrakou, Trissevgeni;  Müller, Jean-François;  De Smedt, Isabelle;  van Geffen, Jos;  Marais, Eloise A;  Horner, Rebekah P;  Millet, Dylan B;  Wells, Kelly C;  Guenther, Alex B;   - view fewer <#>    (2025)    Natural emissions of VOC and NOx over Africa constrained by TROPOMI HCHO and NO2 data using the MAGRITTEv1.1 model.                   Atmospheric Chemistry and Physics , 25  (5)   pp. 2863-2894.    10.5194/acp-25-2863-2025 <https://doi.org/10.5194/acp-25-2863-2025>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10206253/1/Opacka-2025-ACP-VOCs-NOx-Africa.pdf