PNNL

Abstract

Climate modification by stratospheric SO2 injections to form sulfate aerosols may alter the spectral and angular distributions of solar ultraviolet and visible radiation reaching the Earth’s 16 surface, with potential consequences to environmental photobiology and photochemistry. We used modeling results from the CESM1 (WACCM) stratospheric aerosol geoengineering large ensemble (GLENS) project with the RCP8.5 emission scenario and with geoengineering consisting of SO2 injections at 2 different heights in the stratosphere. Zonally and monthly (March) averaged vertical profiles of O3, SO2, and sulfate aerosols at 30N and 70N served as input to a radiative transfer model to compute biologically active irradiances for DNA damage, UV Index, Photosynthetically Active Radiation (PAR), and two key tropospheric photodissociation coefficients, jO1D for O3 + h? (?