Aeroglob

Quantification et caractérisation des aérosols atmosphérique à partir de mesure de l'irradiance globale

Mots clés
Aerosol, beam and global irradiance

Résumé
On the basis of the broadband simplified Solis clear sky model, a method is developed to quantify and characterize the atmospheric aerosols content and type from global and/or beam hourly irradiance measurements.

The use of this simplified model makes possible the determination of the broadband aerosol optical depth from the beam and global measurements separately. Day by day, on an hourly basis, the irradiance versus solar time curve is compared to the corresponding clear sky model, and a best fit is done for the aerosol otpical depth varying from 0.005 to 0.5, and for four different aerosol types. The result consists of four daily global and four daily beam aerosol optical depth values, one for each aerosol type. As the transmittance of the global and the beam irradiance components differs with the different aerosol types, the retrieved aerosol optical depths will also be different, depending on the type and the component.

The first issue of the method is the possibility to retrieve an aerosol optical depth from the sole global irradiance. If the beam component is also available, the comparison between the values retrieved from the global and the beam irradiances will then give an indication on the aerosol type.