Atmospheric radiative transfer parametrization for solar energy yield calculations on buildings

In this paper the practical approach to evaluate the incoming solar radiation on buildings based on atmospheric composition and cloud cover is presented. The effects of absorption and scattering due to atmospheric composition is taken into account to calculate, using radiative transfer models, the net incoming solar radiation at surface level. A specific validation of the Alpine Region in Europe is presented with a special focus on the region of South Tyrol.

💡 Research Summary

The paper presents a practical methodology for estimating the solar radiation that reaches building façades by explicitly accounting for atmospheric composition and cloud cover. Recognizing that conventional building‑energy simulations often rely on coarse meteorological averages or fixed transmittance values, the authors develop a parameterized atmospheric radiative‑transfer model that integrates wavelength‑dependent absorption and scattering by gases (water vapour, CO₂, CH₄, etc.) and aerosols, as well as dynamic cloud effects.

Data acquisition begins with a comprehensive atmospheric database compiled from surface stations, radiosondes, and satellite products (e.g., column water vapour, aerosol optical depth). Spectroscopic absorption coefficients are drawn from the latest HITRAN releases, while aerosol scattering is modeled using Mie theory based on measured size distributions. Cloud influence is treated through a two‑step approach: (1) cloud type classification (high, mid, low) provides typical geometrical thickness and particle size parameters; (2) cloud optical depth is computed and weighted by the observed cloud‑cover fraction, allowing the model to capture rapid cloud‑induced variability.

The radiative‑transfer calculation follows the Lambert‑Beer law applied to each 5 nm spectral band from 300 nm to 2500 nm: τ(λ)=exp