Abstract
Tropospheric ozone contributes significantly to human-induced greenhouse warming. Calculations from satellite measurements of spectral radiance suggest that ozone in the upper troposphere caused an average reduction in clear-sky outgoing long-wave radiation over the oceans of 0.48±0.14 W m−2 for the year 2006 between 45∘ S and 45∘ N. Radiative forcing from anthropogenic ozone in the troposphere is an important factor in climate change1, with an average value of 0.35 W m−2 according to the Intergovernmental Panel for Climate Change1 (IPCC). IPCC model results range from 0.25 to 0.65 W m−2, owing to uncertainties in the estimates of pre-industrial concentrations of tropospheric ozone1,2,3, and in the present spatial and temporal distributions of tropospheric ozone4,5,6,7,8, which are much more variable than those of longer-lived greenhouse gases such as carbon dioxide. Here, we analyse spectrally resolved measurements of infrared radiance from the Tropospheric Emission Spectrometer9 on board the NASA Aura satellite, as well as corresponding estimates of atmospheric ozone and water vapour, to obtain the reduction in clear-sky outgoing long-wave radiation due to ozone in the upper troposphere over the oceans. Accounting for sea surface temperature, we calculate an average reduction in clear-sky outgoing long-wave radiation for the year 2006 of 0.48±0.14 W m−2 between 45∘ S and 45∘ N. This estimate of the clear-sky greenhouse effect from tropospheric ozone provides a critical observational constraint for ozone radiative forcing used in climate model predictions.
Paper version not known (
Free)
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call