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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/13005

Title: Evidence of Long-Term Trend of Visibility in the Sahel and Coevolution with Meteorological Conditions and Vegetation Cover during the Recent Period
Authors: Silué, Siélé
N’Datchoh, Touré E.
Diedhiou, Arona
Quansah, Emmanuel
Doumbia, Madina
Keywords: Visibility
Issue Date: 2019
Publisher: Atmospheric and Climate Sciences
Citation: Atmospheric and Climate Sciences,
Abstract: In this study, the long term trend of the observed visibility data used directly (without conversion into dust concentrations) over Sahel was investigated between 1957 and 2013. Then, to review the influence of atmospheric factors and land surface conditions on this trend, the coevolution between the visibility and the dust surface mass concentration from MERRA-2 (Modern-Era Retrospective analysis for Research and Applications) reanalysis, the in-situ surface meteorological data (rainfall, relative humidity, wind speed, and air temperature), as well as the Normalized Difference Vegetation Index (NDVI) were analyzed from 2000 to 2013. We showed that the horizontal visibility has significantly decreased since the 1970s. The coevolution between the visibility and the dust surface mass concentration revealed that visibility decreased significantly with increments in dust concentrations. Visibility increases with rainfall and relative humidity. It is greater in areas of high vegetation cover than in deforested areas. Visibility is weakly correlated with wind speed and air temperature but generally, wind leads to a decrease in visibility, while warm air temperature is associated with a clearer sky and hence, high visibility. The worst visibility in the dry season results from high dust concentrations due to warm and dry wind conditions and less vegetation cover. Rainfall, relative humidity and vegetation cover are the dominant factors contributing to the decrease of dust loading in the Sahel.
Description: This article is published in Atmospheric and Climate Sciences and also available at DOI: 10.4236/acs.2019.93025
URI: 10.4236/acs.2019.93025
Appears in Collections:College of Science

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