In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 18, No. 1 ( 2018-01-16), p. 445-465
Abstract:
Abstract. Carbon monoxide, CO, and fine atmospheric particulate matter,
PM2.5, are analyzed over the Guinean Gulf coastal region using the
WRF-CHIMERE modeling system and observations during the beginning of the
monsoon 2006 (from May to July), corresponding to the Africa
Multidisciplinary Monsoon Analysis (AMMA) campaign period. Along the Guinean Gulf coast, the contribution of long-range pollution
transport to CO or PM2.5 concentrations is important. The contribution
of desert dust PM2.5 concentration decreases from ∼ 38 % in
May to ∼ 5 % in July. The contribution of biomass burning
PM2.5 concentration from Central Africa increases from
∼ 10 % in May to ∼ 52 % in July. The anthropogenic
contribution is ∼ 30 % for CO and ∼ 10 % for
PM2.5 during the whole period. When focusing only on anthropogenic pollution, frequent northward transport
events from the coast to the Sahel are associated with periods of low wind
and no precipitation. In June, anthropogenic PM2.5 and CO concentrations
are higher than in May or July over the Guinean coastal region. Air mass
dynamics concentrate pollutants emitted in the Sahel due to a meridional
atmospheric cell. Moreover, a part of the pollution emitted remotely at the
coast is transported and accumulated over the Sahel. Focusing the analysis on the period 8–15 June, anthropogenic pollutants
emitted along the coastline are exported toward the north especially at the
beginning of the night (18:00 to 00:00 UTC) with the establishment of the
nocturnal low level jet. Plumes originating from different cities are mixed
for some hours at the coast, leading to high pollution concentration, because
of specific disturbed meteorological conditions.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-18-445-2018
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2018
detail.hit.zdb_id:
2069847-1
Permalink
