Open AccessTemporal and spatial variations of the atmospheric dust loading throughout West Africa over the last thirty years
Author(s) -
G. M. N’Tchayi,
JeanLouis Bertrand,
Michel Legrand,
J. Baudet
Publication year - 1994
Publication title -
annales geophysicae
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.522
H-Index - 93
eISSN - 1432-0576
pISSN - 0992-7689
DOI - 10.1007/s00585-994-0265-3
Subject(s) - haze , visibility , arid , environmental science , period (music) , atmosphere (unit) , climatology , atmospheric sciences , economic shortage , atmospheric dust , physical geography , meteorology , geography , aerosol , geology , paleontology , linguistics , philosophy , physics , government (linguistics) , acoustics
The dust haze conditions, typical of the\udAfrican atmosphere south of the Sahara, are a result of wind-generated dust from\udarid lands. The magnitude of the dust haze is evaluated for the 30-year period\udbeginning in 1957 by calculating the number of occurrences where the observed\udvisibility was reduced below threshold values of 10 km and 5 km. The frequency\udof low visibility was several times greater for the 1977-1986 period than for\udthe 1957-1966 period. Large decreases in visibility are observed after the\udsevere droughts of 1972-1973 and 1982-1984. Contrasting regional differences of\udthe dustiness evolution are noticed. These differences are closely related to\udthe differences in the regional rainfall evolution. The increase in dustiness is\udbelieved to arise from dust produced in new desertic areas which result from\udrainfall shortages along the southern border of the Sahara