Atmospheric Chemistry and Physics (Nov 2012)
Impact of very short-lived halogens on stratospheric ozone abundance and UV radiation in a geo-engineered atmosphere
Abstract
The impact of very short-lived (VSL) halogenated source species on the ozone layer and surface erythemal ultraviolet radiation (UV<sub>ERY</sub>) is investigated in the context of geo-engineering of climate by stratospheric sulfur injection. For a projected 2040 model atmosphere, consideration of VSL halogens at their upper limit results in lower ozone columns and higher UV<sub>ERY</sub> due to geo-engineering for nearly all seasons and latitudes, with UV<sub>ERY</sub> rising by 12% and 6% in southern and northern high latitudes, respectively. When VSL halogen sources are neglected, future UV<sub>ERY</sub> increases due to declines in ozone column are nearly balanced by reductions of UV<sub>ERY</sub> due to scattering by the higher stratospheric aerosol burden in mid-latitudes. Consideration of VSL sources at their upper limit tips the balance, resulting in annual average increases in UV<sub>ERY</sub> of up to 5% in mid and high latitudes. Therefore, VSL halogens should be considered in models that assess the impact of stratospheric sulfur injections on the ozone layer.
