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Previsibility of mineral dust concentrations: The
CHIMERE-DUST forecast during the first AMMA experiment
dry season, 2009,
MENUT Laurent, Isabelle CHIAPELLO, Cyril MOULIN
Journal of Geophysical Research, 114, D07202, doi:10.1029/2008JD010523, Paper [PDF]:
Abstract
The previsibility of Northern Africa dust events is quantified using daily numerical
forecast simulations for the next three days. The dust concentrations fields, modeled by
CHIMERE-DUST, are first evaluate by comparisons to AERONET surface data, OMI and MSG
Seviri satellite measurements. The accuracy and spread between measurements and model are
discussed focussing on the first short observation period of the AMMA experiment in
western Africa, with a simulation period ranging from January to March 2006. Second, the
previsibility of dust is estimated by comparing model results for different leads in a
forecats mode. The model skill is evaluate in term of capability to forecast (i) the
surface wind speed (the key process for dust emissions), (ii) the dust emissions
(depending on the wind speed as well as numerous others uncertain parameters, including
threshold values on the friction velocity) and (iii) the transport of aerosols from source
to remote areas (depending of horizontal transport, convection etc.). It is shown that
emissions forecast can vary up to 80% (close to the sources) and that final forecasted
dust concentrations and relative optical thickness do not exceed 40% and 20% in forecast
variability.
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