Analysis of temporal and spatial variability of total column ozone over West Africa using daily TOMS measurements

Oluleye, Ayodeji; Okogbue, Emmanuel Chilekwu

doi:10.5094/apr.2013.044

Cited by 21 publications

(19 citation statements)

References 27 publications

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“…However, further investigations are necessary, knowing that the determination of the effective start of the rainy season is capital for sowing in such regions. The analysis of the ECMWF atmospheric profiles shows that the Maroua atmosphere state and dynamics present many similarities with what was reported in some studies in West Africa, a neighboring zone [9,11,47,48]. Adding to this, the good correlation coefficients obtained between ECMWF and measured meteorological data at ground level show the capacity of ECMWF profiles to characterize the Maroua atmosphere and therefore show the possibility to use these in solar radiation simulation.…”

Section: Vertically Distributed Quantitiessupporting

confidence: 51%

“…The ozone concentration followed the TCWV seasonal variations; thus the minimum occurred during the dry season, while the maximum occurred during the wet season. These variations are usual and were similar to those in N'djamena (12.12 • N, 14.92 • E), a neighboring area, where, although the high insolation dry period appears to be favorable for an abundant ozone production, the contrary occurs for the TCO variation, which is driven by wind dynamics over West Africa [48]. The same type of evolution is also observed in tropical Indian regions (latitudes <20 • N), where TCO concentration raise and the peak has been related to the monsoon occurrence [49].…”

Section: Total Column Quantitiesmentioning

confidence: 56%

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ECMWF Atmospheric Profiles in Maroua, Cameroon: Analysis and Overview of the Simulation of Downward Global Solar Radiation

et al. 2018

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Atmospheric analysis data from the European Center for Medium-Range Weather Forecasts (ECMWF) have been acquired and are used to characterize the meteorological situation in Maroua, Cameroon (10.614 • N, 14.361 • E) at 12:00 UTC. These are then used to simulate downward global solar radiation (DGSR) with the moderate-resolution transmittance (MODTRAN) radiative transfer code (RTC). In comparison with meteorological data measured during the year 2014 in Maroua, ECMWF atmospheric quantities at ground level, in general, showed good correlation coefficients and slight differences. It is shown that ECMWF atmospheric profiles can thus be used to complete the scarce atmospheric data and to study the atmosphere state and dynamics, such as the African monsoon phenomenon detected in this region, which regulates the rainy season. In addition, they are more suitable to simulate clear-sky DGSR compared to MODTRAN standard atmospheric profiles. The causes and effects of the substantial bias and weak correlation coefficient observed with ECMWF wind data and the constant underestimation of simulated DGSR in comparison with ground-based measurements are investigated. The paper emphasizes the need for a better characterization of the Maroua atmosphere state and dynamics as well as the simulation of more accurate and reliable DGSR under any atmospheric conditions.

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Section: Vertically Distributed Quantitiessupporting

confidence: 51%

Section: Total Column Quantitiesmentioning

confidence: 56%

ECMWF Atmospheric Profiles in Maroua, Cameroon: Analysis and Overview of the Simulation of Downward Global Solar Radiation

et al. 2018

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“…'Backscattered' radiation is solar radiation that has penetrated to the Earth's lower atmosphere. There, it is scattered by air molecules and clouds back through the stratosphere to the satellite sensors [8]. It is important to note that TOMS cannot measure ozone below clouds.…”

Section: Datamentioning

confidence: 99%

“…The occurrence of maximum ozone concentration with the peak tropical rainfall could possibly be attributed to the active weather system during the months. Active weather ensures strong mixing and vigorous transport which causes the transportation of ozone from the tropical stratosphere into the mid and high latitudinal region [8]. The tropical rainfall season is characterized with minimum surface temperature and evaporation.…”

Section: Monthly Distribution Of Total Ozone Columnmentioning

confidence: 99%

“…The production and depletion appeared to be less problematic since both are sufficiently slow and thus capable of removing any irregularity in either of the ways. Anthropogenic depletion of ozone by ChloroFluoroCarbon (CFC) that finds its way to the stratosphere is the source of concern because the process is fast and the depleting agents are abundant [4]. Ozone varies across the latitudinal and longitudinal and also varies hourly, daily, monthly, seasonally and yearly.…”

Section: Introductionmentioning

confidence: 99%

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The Influence of Rainfall and Temperature on Total Column Ozone over West Africa

Eresanya¹,

Oluleye²,

Daramola³

2017

AIR

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This study aims at analyzing the influence of rainfall and temperature on Total Column Ozone (TCO) over West Africa. It provides adequate information on the spatial variability of total column ozone concentration, temperature distribution across latitudinal zones, monthly distribution and inter-annual variability of total ozone column and interrelationship between monthly ozone and distribution of precipitation rate over West Africa. The result of this work shows that, there are significant interconnectivities between total ozone column variability with precipitation and temperature. The correlation between Annual coefficient of Relative Variation (ACRV) of Total Column Ozone (TCO) with average annual temperature and average precipitation shows that there is correlation in ACRV of total ozone column trends over West Africa with temperature and precipitation. A strong positive value correlation was observed between the ACRV of ozone and average annual temperature which increases from 25°C to 29°C at the hot arid north of the region and the mean monthly maximum ozone Coincides with the tropical summer rainfall over West Africa between June and September, which showed that there is a significant relationship between rainfall and total ozone column over West Africa. Temperature and ozone tend to increase across the latitude while rainfall decreases across the latitude. These observations suggest significant Original Research Article

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Aerosols’ variability and their relationship with climatic parameters over West Africa

Ochei,

Oluleye,

Wolke

et al. 2023

Environ Monit Assess

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Aerosols’ influences on Earth’s climate have been documented by several authors. This ranges from scattering and reflecting of shortwave radiation (direct effect) which is also regarded as the “Whitehouse Effect,” to the ability to act as condensation nuclei (indirect effect) which results in cloud droplet formation. This broad summary of aerosol’s effect on earth’s climate has in turn affected some other weather variables either positively or negatively depending on people’s perspectives. This work was done in a view to ascertaining some of these claims by determining the statistical significance of some certain aerosol’s relationships with some selected weather variables. This was done over six (6) stations across the West African region to represent the climatic zones from the rainforest around the coasts to the desert of the Sahel. Data used consist of aerosol types (biomass burning, carbonaceous, dust, and PM2.5) and climatic types (convective precipitation, wind speed, and water vapor) over a period of 30 years, with the python and ferret programs explicitly used for the graphical analyses. Climatologically, locations close to the point source seem to record more of the presence of the pollutants than the farthest ones. Results indicated that aerosols were more pronounced in the dry months of NDJF over the rainforest region depending on the latitudinal position of the location. The relationship result showed a negative correlation between convective precipitation and aerosols, except carbonaceous. But the strongest relationship can be found between water vapor and the selected aerosol types.

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Analysis of temporal and spatial variability of total column ozone over West Africa using daily TOMS measurements

Cited by 21 publications

References 27 publications

ECMWF Atmospheric Profiles in Maroua, Cameroon: Analysis and Overview of the Simulation of Downward Global Solar Radiation

ECMWF Atmospheric Profiles in Maroua, Cameroon: Analysis and Overview of the Simulation of Downward Global Solar Radiation

The Influence of Rainfall and Temperature on Total Column Ozone over West Africa

Aerosols’ variability and their relationship with climatic parameters over West Africa

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