Retrieving Surface Solar Irradiance from Himawari-8: a Physics Based Approach and its Validation

This paper presents a physics-based method to estimate all components of surface solar irradiance (SSI) from Himawari-8 imagery. Cloud parameters were retrieved from satellite data, and SSI calculated using radiative transfer through look-up-tables. Detailed validation using 3 years of high quality 1-minute surface measurements at 11 stations across Australia consistently showed low bias (≤ 5 W/m
²
) across timescales for all SSI components, and rapidly reducing RMSE with increasing averaging period. Issues in validation using in-situ measurements will be discussed. We will also present an accurate analytical model for the calculation of circumsolar radiance applicable to clear and cloudy sky conditions.