Measurements of  nitric oxide and ammonia soil  fluxes from a wet
savanna ecosystem site in West  Africa during the DACCIWA field
campaign

Pacifico, Federica; Delon, Claire; Jambert, Corinne; Durand, Pierre; Morris, Eleanor; Evans, M. J.; Lohou, Fabienne; Derrien, Solène; Donnou, Venance H. E.; Houeto, A.; Martínez, Irene Reinares; Brilouet, Pierre‐Etienne

doi:10.5194/acp-2017-1198

Cited by 3 publications

(3 citation statements)

References 19 publications

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“…At Savè, the Karlsruhe Institute of Technology (KIT) and the Paul Sabatier University (UPS) have set up meteorological and atmospheric composition measurements. UPS installed a chemical analyzer (ThermoEnvironment instrument), which measured NO 2 , NO, and CO surface concentrations (Pacifico et al, 2018;Kalthoff et al, 2018). Raw observations acquired at 10 s are averaged hourly.…”

Section: Observational Datasetsmentioning

confidence: 99%

Diurnal cycle of coastal anthropogenic pollutant transport over southern West Africa during the DACCIWA campaign

et al. 2019

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Abstract. During the monsoon season, pollutants emitted by large coastal cities and biomass burning plumes originating from central Africa have complex transport pathways over southern West Africa (SWA). The Dynamics–Aerosol–Chemistry–Cloud Interactions in West Africa (DACCIWA) field campaign has provided numerous dynamical and chemical measurements in and around the super-site of Savè in Benin (≈185 km away from the coast), which allows quantification of the relative contribution of advected pollutants. Through the combination of in situ ground measurements with aircraft, radio-sounding, satellite, and high-resolution chemistry-transport modeling with the CHIMERE model, the source attribution and transport pathways of pollutants inland (here, NOx and CO) are carefully analyzed for the 1–7 July 2016 period. The relative contributions of different sources (i.e., emissions from several large coastal cities) to the air quality in Savè are characterized. It is shown that a systematic diurnal cycle exists with high surface concentrations of pollutants from 18:00 to 22:00 UTC. This evening peak is attributed to pollution transport from the coastal city of Cotonou (Benin). Numerical model experiments indicate that the anthropogenic pollutants are accumulated during the day close to the coast and transported northward as soon as the daytime convection in the atmospheric boundary layer ceases after 16:00 UTC, reaching 8∘ N at 21:00 UTC. When significant biomass burning pollutants are transported into continental SWA, they are mixed with anthropogenic pollutants along the coast during the day, and this mixture is then transported northward. At night, most of the coastal anthropogenic plumes are transported within the planetary boundary layer (below about 500 m above ground level), whereas the biomass burning pollutants are mostly transported above it, thus generally not impacting ground level air quality.

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Section: Observational Datasetsmentioning

confidence: 99%

Diurnal cycle of coastal anthropogenic pollutant transport over southern West Africa during the DACCIWA campaign

et al. 2019

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“…Nitrogen monoxide (NO) and nitrogen dioxide (NO 2 ) were measured on an 8 m high tower and carbon monoxide (CO) was measured separately at 3.50 m above ground level (a.g.l. NO, before and after the campaign, respectively, and 9.28 ppm for NO 2 , both with 5 % precision (Pacifico et al, 2018).…”

Section: Gas Concentrations Of No X and Comentioning

confidence: 93%

The Vertical Variability of Black Carbon Observed in the Atmospheric Boundary Layer during DACCIWA

Altstädter¹,

Deetz²,

Vogel³

et al. 2019

Preprint

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Abstract. The vertical variability of the black carbon (BC) mass concentration in the atmospheric boundary layer (ABL) is analysed during the West-African Monsoon (WAM) season. BC was measured with a micro aethalometer (model AE51, AethLabs) integrated in the payload bay of the unmanned research aircraft ALADINA (Application of Light-weight Aircraft for Detecting IN situ Aerosol) as part of the field experiment of the DACCIWA (Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa) project. In total, 53 measurement flights were performed at the local airfield of Save, Benin, in the period of 2–16 July 2016. The mean results show a high variability of BC (1.79 to 2.42 ± 0.31 μg/m3) influenced by the stratification of the ABL during the WAM. The model COSMO-ART (Consortium for Small-scale Modelling–Aerosols and Reactive Trace gases) was applied for the field campaign period and used in order to investigate possible sources of the measured BC. The model output was compared with the BC data on two selected measurement days (14 and 15 July 2016). The modeled vertical profiles of BC show that the observed BC was already altered, as the size was mainly dominated by the accumulation mode. Further, the calculated vertical transects of wind speed and BC showed that the measured BC layer was transported from the south with maritime inflow, but was mixed vertically after to the onset of the nocturnal low-level jet (NLLJ) at the measurement site. The validations and the ground observations of gas concentrations NOx and CO confirm that primary emission could be excluded during the case study, in contrast to initially expected. The case underlines the important role of BC transport processes in the WAM area.

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“…NO in N 2 diluted with zero air. Reference NO and NO 2 were ISO 6141:2015 certified at 8.73 and 8.58 ppm for NO before and after the campaign, respectively, and 9.28 ppm for NO 2 , both with 5 % precision (Pacifico et al, 2019).…”

Section: Gas Concentrations Of No X and Comentioning

confidence: 99%

The vertical variability of black carbon observed in the atmospheric boundary layer during DACCIWA

et al. 2020

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Abstract. This study underlines the important role of the transported black carbon (BC) mass concentration in the West African monsoon (WAM) area. BC was measured with a micro-aethalometer integrated in the payload bay of the unmanned research aircraft ALADINA (Application of Light-weight Aircraft for Detecting IN situ Aerosol). As part of the DACCIWA (Dynamics–Aerosol–Chemistry–Cloud Interactions in West Africa) project, 53 measurement flights were carried out at Savè, Benin, on 2–16 July 2016. A high variability of BC (1.79 to 2.42±0.31 µg m−3) was calculated along 155 vertical profiles that were performed below cloud base in the atmospheric boundary layer (ABL). In contrast to initial expectations of primary emissions, the vertical distribution of BC was mainly influenced by the stratification of the ABL during the WAM season. The article focuses on an event (14 and 15 July 2016) which showed distinct layers of BC in the lowermost 900 m above ground level (a.g.l.). Low concentrations of NOx and CO were sampled at the Savè supersite near the aircraft measurements and suggested a marginal impact of local sources during the case study. The lack of primary BC emissions was verified by a comparison of the measured BC with the model COSMO-ART (Consortium for Small-scale Modelling–Aerosols and Reactive Trace gases) that was applied for the field campaign period. The modelled vertical profiles of BC led to the assumption that the measured BC was already altered, as the size was mainly dominated by the accumulation mode. Further, calculated vertical transects of wind speed and BC presume that the observed BC layer was transported from the south with maritime inflow but was mixed vertically after the onset of a nocturnal low-level jet at the measurement site. This report contributes to the scope of DACCIWA by linking airborne BC data with ground observations and a model, and it illustrates the importance of a more profound understanding of the interaction between BC and the ABL in the WAM region.

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Measurements of nitric oxide and ammonia soil fluxes from a wet savanna ecosystem site in West Africa during the DACCIWA field campaign

Cited by 3 publications

References 19 publications

Diurnal cycle of coastal anthropogenic pollutant transport over southern West Africa during the DACCIWA campaign

Diurnal cycle of coastal anthropogenic pollutant transport over southern West Africa during the DACCIWA campaign

The Vertical Variability of Black Carbon Observed in the Atmospheric Boundary Layer during DACCIWA

The vertical variability of black carbon observed in the atmospheric boundary layer during DACCIWA

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