The Effect of Atmospheric Stability on the Surface-Layer Characteristics in a Low-Wind Area of Tropical West Africa

Jegede, Olugbemiro J.; Fasheun, T. A.; Adeyefa, Z.D.; Balogun, Ahmed A.

doi:10.1023/a:1000447600185

Cited by 10 publications

(4 citation statements)

References 13 publications

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“…ms (Jegede et al, 1997;Ayoola et al, 2014). It has a dimension approximated 1500 m by 300 m. Typical varieties of arable crops; such as maize, cassava, water melon and fruits are planted every year and the area is characterized with a few scattered trees.…”

Section: Methodology Site Descriptionmentioning

confidence: 99%

Diurnal variation of carbon dioxide flux above growing cowpea (<i>Vigna unguiculata [L] Walp.</i>) at an agricultural site in Ile-Ife, Nigeria

Ajao¹,

Jegede²

2019

Ife Journal of Science

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The goal of this study was to investigate the diurnal variation of carbon dioxide (CO) flux above cowpea 2 (Vigna unguiculata [L.] Walp) in relation to its phenological stages of growth. The experimental site was an agricultural area located at the Teaching and Research farm of Obafemi Awolowo University, Ile-Ife, Nigeria.. The planting of cowpea covered two cycles, March-June and August-November, 2015, which represented dryto-wet and wet-to-dry seasonal transitions in the area respectively. An eddy covariance system was deployed on site from which turbulent flux of carbon dioxide had been determined. In addition, net radiation, photosynthetically active radiation (PAR), leaf surface temperature, soil moisture and thermal parameters were measured within the plant environment. Concentration of CO at the study location decreased by about 50 % to 2-3-2 minimum values, 650 mgm at 1500 hrs (LT), which is coincident with maximum PAR value of 1800 Wm .-2-1 From sunset until dawn, the CO flux measured increased steadily from about 0.2 mgm s around 1800 hrs (LT) 2-2-1 to reach maximum value, about 0.5 mgm s at 0300 hr. Irrespective of growth stage of the plant, CO flux was 2 maximum during nighttime.

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Section: Methodology Site Descriptionmentioning

confidence: 99%

Diurnal variation of carbon dioxide flux above growing cowpea (<i>Vigna unguiculata [L] Walp.</i>) at an agricultural site in Ile-Ife, Nigeria

Ajao¹,

Jegede²

2019

Ife Journal of Science

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“…In AERMOD, if the boundary layer is stable, only two limits for the horizontal dispersion are considered: the coherent plume limit generated by shifting wind and the random plume limit when the plume spread is assumed uniformly distributed throughout the area (Cimorelli et al, 2005;Perry et al, 2005;Venkatram et al, 2004). It should also be noted that surface albedo inputs in this case were taken from literature values (Jegede et al, 1997). Nevertheless, AERMOD values were much lower compared with the non-buoyant source estimates from ADMS taking January 2015 as a typical scenario.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Dispersion of gas flaring emissions in the Niger delta: Impact of prevailing meteorological conditions and flare characteristics

Fawole

Cai

Abiye

et al. 2019

Environmental Pollution

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An understanding of the dispersion and level of emissions source of atmospheric pollutants; whether point, area or volume sources, is required to inform policies on air pollution and dayto-day predictions of pollution level. Very few studies have carried out simulations of the dispersion pattern and ground-level concentration of pollutants emitted from real-world gas flares. The limited availability of official data on gas flares from the oil and gas industries makes accurate dispersion calculations difficult. Using ADMS 5 and AERMOD, this study assessed the sensitivity of dispersion and ground-level concentration of pollutants from gas flares in the Niger Delta to prevailing meteorological condition; fuel composition; and flare size. Although, during the non-WAM (West African Monsoon) months (November and March), the simulated ground-level concentrations of pollutants from a single flare are lower, the dispersion of pollutants is towards both the inland and coastal communities. In the WAM months, the ground-level concentrations are higher and are dispersed predominantly over the inland communities. Less buoyant plumes from smaller flares (lower volume flow rates) and/or flaring of fuel with lower heat content results in higher ground-level concentrations in areas closer to the flare. Considering the huge number of flares scattered around the region, a mitigation of the acute local pollution level would be to combine short stacks flaring at lower volume flow rates to enhance the volume flow rate of a single exhaust, and hence, the buoyancy of the plume exiting the stack. Main finding Flare and fuel characteristics significantly affects the dispersion pattern and ground-level concentration of pollutants. There is greater population dose during the non-WAM months.

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“…Previous studies using wind direction as to characterize atmospheric stability have done so with limited geographic coverage and a focus on temporal averaging (i.e., climatology) over the instantaneous characterization possible with data acquired from the AWAKEN campaign. [17][18][19]…”

Section: Introductionmentioning

confidence: 99%

Extracting Atmospheric Stability Information from Dual-Doppler Radar Scans in the AWAKEN Campaign

Nadolsky,

Schroeder,

Hirth

2024

J. Phys.: Conf. Ser.

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Dual-Doppler (DD) derived wind direction (β) fields are used in a novel approach to assess atmospheric stability by way of power spectral density (PSD) and bulk statistical analyses. Data on atmospheric stability, thermodynamic profiles, and wind behavior, as acquired during the AWAKEN campaign, are examined for a measurement time period featuring two stability transitions to analyze differences in flow structure as a function of stability regime. Analysis of the β fields yielded promising results when compared to stability regime and can be applied to other cases.

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The Effect of Atmospheric Stability on the Surface-Layer Characteristics in a Low-Wind Area of Tropical West Africa

Cited by 10 publications

References 13 publications

Diurnal variation of carbon dioxide flux above growing cowpea (<i>Vigna unguiculata [L] Walp.</i>) at an agricultural site in Ile-Ife, Nigeria

Diurnal variation of carbon dioxide flux above growing cowpea (<i>Vigna unguiculata [L] Walp.</i>) at an agricultural site in Ile-Ife, Nigeria

Dispersion of gas flaring emissions in the Niger delta: Impact of prevailing meteorological conditions and flare characteristics

Extracting Atmospheric Stability Information from Dual-Doppler Radar Scans in the AWAKEN Campaign

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