Ruiz-Arias, J.A., University of JaŽn, Spain, Dudhia,
J., NCAR, Gueymard, C., Pozo-V‡zquez, D., University of JaŽn, Spain
Numerical Weather
Prediction (NWP) models constitute a very promising tool for solar resource
assessment and forecasting. However, they still need further development to
respond to the specific requirements of the solar industry. Very usually, NWP
do not provide the direct component (DNI) of the solar irradiance, which is
required for concentrating solar energy applications. Additionally, aerosol
effect has most often been oversimplified. However, current satellite imagery
is providing a rich source of broad measurements, which opens new avenues of
research.
In this contribution, we present
preliminary results of a new parameterization of the aerosol optical depth
(AOD) introduced in the shortwave GSFC scheme to yield DNI from the total AOD
at 550 nm. The performance of the model has been tested based on NOAAŐs SURFRAD
radiometric stations. The methodology reduces the MBE and RMSE in global
horizontal irradiance (GHI) and DNI by more than 50% on clear-sky days. On
August 21st, 2009 at the Boulder (Colorado) BSRN station, for instance, the MBE
was reduced from 7% to 2% and the RMSE from 9% to 4% for GHI. For DNI, the
improvement was 17% to 3%, and 24% to 7%, respectively.