Quantifying the tropospheric ozone radiative effect and its temporal evolution in the satellite-era.

Using state-of-the-art satellite ozone profile products, and chemical transport model, we provide an updated estimate of the tropospheric ozone radiative effect (TO₃RE) and observational constraint on its variability over the decade 2008–2017. Previous studies have shown the short-term (i.e. a few years) globally weighted average TO₃RE to be 1.17±0.03 W/m², while our analysis suggests that the long-term (2008–2017) average TO₃RE to be 1.21–1.28 W/m². Over this decade, the modelled/observational TO₃RE linear trends show negligible change (i.e. ±0.1 %/year), so the tropospheric ozone radiative contribution to climate has remained stable with time. Two model sensitivity experiments fixing emissions and meteorology to one year (i.e. start year – 2008) show that ozone precursor emissions (meteorological factors) have had limited (substantial) impacts on the long-term tendency of globally weighted average TO₃RE. Here, the meteorological variability in the tropical/sub-tropical upper troposphere is dampening any tendency in TO₃RE from other factors (e.g. emissions, atmospheric chemistry). [ABSTRACT FROM AUTHOR]