In clear-sky conditions, one of the largest sources of error for predictions of solar irradiance and solar power is the aerosol optical depth (AOD). Direct normal irradiance (DNI) is particularly sensitive to AOD, while global horizontal irradiance (GHI) is less sensitive but still impacted. Therefore, particularly for concentrated solar power (CSP) plants, but also for standard photovoltaic (PV) solar power plants, accurate predictions of the AOD are crucial for accurate predictions of solar irradiance and power. Aerosol loading can also be significant in arid regions such as the Arabian Desert, where a number of new solar power plants have been or will soon be constructed, including the Shagaya Renewable Energy Park in western Kuwait.
In this study we present a climatological analysis of AOD forecasts over a 1-year period from the Global Forecast System (GFS) model and the Goddard Earth Observing System Model, Version 5 (GEOS-5). AOD predictions from both models are validated against Aerosol Robotic Network (AERONET) observing stations across the Arabian Desert region, to determine which of those AOD forecasting models yield better predictions. In addition, we will also compare AOD forecasts from the Weather Research and Forecasting (WRF) model using a new explicit dust model, with aerosol boundary conditions given by a monthly climatological aerosol dataset, and from the WRF model with the explicit dust model with aerosol boundary conditions given by forecasts from either GFS or GEOS5, whichever is better. Assessments of solar irradiance forecasts at Shagaya in Kuwait from these models will also be presented.