Diurnal evolution of the direct (B, blue line), diffuse (D, green line), and total (T, red line) surface solar flux between 200 and 1100 nm at four different latitudes during the Northern Hemisphere winter solstice, for τ _d,880  = 1 and τ _ca,12.1  = 0.02. The flux at the TOA (E) is represented by the black line. The values of the legend represent daily irradiation between 200 and 1100 nm in MJ m⁻².