Trends and seasonal variability in ammonia across major biomes in western and central Africa inferred from long-term series of ground-based and satellite measurements

Abstract 3) is the most abundant alkaline component in the atmosphere. Changes in NH3 concentrations have important implications for atmospheric chemistry, air quality, and ecosystem integrity. We present a long-term ammonia (NH3) assessment in the western and central African regions within the framework of the International Network to study Deposition and Atmospheric chemistry in Africa (INDAAF) programme. We analyse seasonal variations and trends in NH3 concentrations and total column densities along an African ecosystem transect spanning dry savannas in Banizoumbou, Niger, and Katibougou, Mali; wet savannas in Djougou, Benin, and Lamto, Côte d'Ivoire; and forests in Bomassa, Republic of the Congo, and Zoétélé, Cameroon. We use a 21-year record of observations (1998–2018) from INDAAF passive samplers and an 11-year record of observations (2008–2018) of atmospheric vertical column densities from the Infrared Atmospheric Sounding Interferometer (IASI) to evaluate NH3 ground-based concentrations and total column densities, respectively. Climatic data (air temperature, rainfall amount, and leaf area index), as well as ammonia emission data of biomass combustion from the fourth version of the Global Fire Emissions Database (GFED4) and anthropogenic sources from the Community Emissions Data System (CEDS), were compared with total NH3 concentrations and total columns over the same periods. Annual mean ground-based NH3 concentrations are around 5.7–5.8 ppb in dry savannas, 3.5–4.7 ppb in wet savannas, and 3.4–5.6 ppb in forests. Annual IASI NH3 total column densities are 10.0–10.7 × 15  molec. cm- 2 × 15  molec. cm- 2 × 15  molec. cm- 2 3 concentrations increase at Bomassa (+ - 1 - - 1 3 total column density measurements show yearly increasing trends at Katibougou (+ - 1 + - 1 + - 1 3 in the INDAAF stations. The results also show that the drivers of trends are (1) agriculture in the dry savanna of Katibougou; (2) air temperature and agriculture in the wet savanna of Djougou and Lamto; and (3) leaf area index, air temperature, residential, and agriculture in the forest of Bomassa.

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch

References and Relationships

• Bibliographic citation: Trends and seasonal variability in ammonia across major biomes in western and central Africa inferred from long-term series of ground-based and satellite measurements ; volume:23 ; number:16 ; year:2023 ; pages:9473-9494 ; extent:22 ; Atmospheric chemistry and physics ; 23, Heft 16 (2023), 9473-9494 (gesamt 22)

Contributors, Places and Time

• Creator: Ossohou, Money ; Hickman, Jonathan Edward ; Clarisse, Lieven ; Coheur, Pierre-François ; Van Damme, Martin ; Adon, Marcellin ; Yoboué, Véronique ; Gardrat, Eric ; Alvès, Maria Dias ; Galy-Lacaux, Corinne

Further information

• DOI: 10.5194/acp-23-9473-2023
• URN: urn:nbn:de:101:1-2023083104235016138413
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 14.08.2025, 10:57 AM CEST