Reconstruction of the integrated spectral irradiance in selected wavelength bands. This reconstruction is based on the composite of the ¹⁰Be South Pole record and neutron monitor data (red curve in Fig. 2). Panels from bottom to top: the 500–600 nm band is representative of the time evolution of the visible irradiance. The CN violet system is one of the most variable bands that is accessible from the ground. The Herzberg continuum is crucial for ozone production in the stratosphere. The Schumann-Runge band is important for heating processes in the middle atmosphere.