Chapter 4 - Spectral Solar Irradiance Estimation in Cloudy-Sky Conditions

Based on previous research on light scattering by cloud particles and the development of radiative transfer models, this chapter delivers a concise overview of computing spectral solar radiation in cloudy-sky conditions and its relevance to solar energy applications. Section 2 introduces the computation of light absorption and scattering by clouds, which is essential for determining cloud transmittance and reflectance. Section 3 builds on that foundation to describe time-efficient radiative transfer models for cloudy-sky conditions. Section 4 evaluates the current empirical models for computing spectral solar irradiances and compares their strengths and limitations with physical models. Finally, Section 5 summarizes the chapter and outlines possible future research on the computation of spectral solar irradiances.