The Narrow Band of Energy That Reaches Earth due to Ozone Depletion

Actinic flux calculated by Madronich showing spectrum of energy received at Earth when ozone is depleted.

A 50% decrease in total column ozone increases the amount of ultraviolet radiation reaching Earth’s surface by ~2 W m-2 between 290 and 340 nm (red shaded area) when Sun is directly overhead (Madronich, 1993). O3 and SO2, absorb solar energy strongly at wavelengths <400 nm. Absorption by O3 typically leads to photodissociation for wavelengths <411 nm. Actinic flux is photons cm-2 s-1, absorption cross section is cm2 per molecule, and increase in UV radiation is mW m-2 nm-1. Absorption data for O3 from (Rothman et al., 2013) and for SO2 from Hermans et al. (2009) and Vandaele et al. (2009).

Last updated 05-Dec-2015    © 2015 Peter L. Ward. All Rights Reserved