On the evaluation of halocarbon radiative forcing and global warming potentials

Daniel, J. S.; Solomon, Susan; Albritton, D. L.

doi:10.1029/94jd02516

Cited by 137 publications

(156 citation statements)

References 32 publications

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“…Up to 1990, The SPARC (Stratospheric Processes and their Role in Climate) monthly mean ozone trend dataset was employed (Randel and Wu 1999;Kiehl et al 1999; see also the SPARC Newsletter article by Karoly 2000). After 1990, the imposed ozone trends assumed a linear relationship between effective equivalent stratospheric chlorine (EESC) and ozone changes (Daniel et al 1995). The burdens of ozone-depleting halogens contributing to EESC were assessed as in Montzka et al (1999).…”

Section: 'Baseline' Simulationsmentioning

confidence: 99%

Stratospheric temperature trends: impact of ozone variability and the QBO

et al. 2009

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In most climate simulations used by the Intergovernmental Panel on Climate Change 2007 fourth assessment report, stratospheric processes are only poorly represented. For example, climatological or simple specifications of time-varying ozone concentrations are imposed and the quasi-biennial oscillation (QBO) of equatorial stratospheric zonal wind is absent. Here we investigate the impact of an improved stratospheric representation using two sets of perturbed simulations with the Hadley Centre coupled ocean atmosphere model HadGEM1 with natural and anthropogenic forcings for the 1979-2003 period. In the first set of simulations, the usual zonal mean ozone climatology with superimposed trends is replaced with a time series of observed zonal mean ozone distributions that includes interannual variability associated with the solar cycle, QBO and volcanic eruptions. In addition to this, the second set of perturbed simulations includes a scheme in which the stratospheric zonal wind in the tropics is relaxed to appropriate zonal mean values obtained from the ERA-40 re-analysis, thus forcing a QBO. Both of these changes are applied strictly to the stratosphere only. The improved ozone field results in an improved simulation of the stepwise temperature transitions observed in the lower stratosphere in the aftermath of the two major recent volcanic eruptions. The contribution of the solar cycle signal in the ozone field to this improved representation of the stepwise cooling is discussed. The improved ozone field and also the QBO result in an improved simulation of observed trends, both globally and at tropical latitudes. The Eulerian upwelling in the lower stratosphere in the equatorial region is enhanced by the improved ozone field and is affected by the QBO relaxation, yet neither induces a significant change in the upwelling trend.

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Section: 'Baseline' Simulationsmentioning

confidence: 99%

Stratospheric temperature trends: impact of ozone variability and the QBO

et al. 2009

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“…Estimates of stratospheric ozone after 1990 were made by assuming a linear relationship between effective equivalent stratospheric chlorine (EESC) and ozone changes (Daniel et al 1995). The burdens of ozone-depleting halogens, which contribute to EESC, were predicted as in Montzka et al (1999).…”

Section: B Ozonementioning

confidence: 99%

Transient Climate Simulations with the HadGEM1 Climate Model: Causes of Past Warming and Future Climate Change

et al. 2006

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The ability of climate models to simulate large-scale temperature changes during the twentieth century when they include both anthropogenic and natural forcings and their inability to account for warming over the last 50 yr when they exclude increasing greenhouse gas concentrations has been used as evidence for an anthropogenic influence on global warming. One criticism of the models used in many of these studies is that they exclude some forcings of potential importance, notably from fossil fuel black carbon, biomass smoke, and land use changes. Herein transient simulations with a new model, the Hadley Centre Global Environmental Model version 1 (HadGEM1), are described, which include these forcings in addition to other anthropogenic and natural forcings, and a fully interactive treatment of atmospheric sulfur and its effects on clouds. These new simulations support previous work by showing that there was a significant anthropogenic influence on near-surface temperature change over the last century. They demonstrate that black carbon and land use changes are relatively unimportant for explaining global mean near-surface temperature changes.The pattern of warming in the troposphere and cooling in the stratosphere that has been observed in radiosonde data since 1958 can only be reproduced when the model includes anthropogenic forcings. However, there are some discrepancies between the model simulations and radiosonde data, which are largest where observational uncertainty is greatest in the Tropics and high latitudes.Predictions of future warming have also been made using the new model. Twenty-first-century warming rates, following policy-relevant emissions scenarios, are slightly greater in HadGEM1 than in the Third Hadley Centre Coupled Ocean-Atmosphere General Circulation Model (HadCM3) as a result of the extra forcing in HadGEM1. An experiment in which greenhouse gases and other anthropogenic forcings are stabilized at 2100 levels and held constant until 2200 predicts a committed twenty-second-century warming of less than 1 K, whose spatial distribution resembles that of warming during the twenty-first century, implying that the local feedbacks that determine the pattern of warming do not change significantly.

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“…Huck et al, 2005;. To attribute changes in stratospheric ozone to depletion by halogens, equivalent effective stratospheric chlorine (EESC) is used as an indicator of the chemical effects of ozone-depleting substances (ODSs) (Daniel et al, 1995). EESC is derived from measurements of ground-based halocarbon concentrations, taking into account their transport times into the stratosphere and their conversion into reactive chlorine (Cl y ) and bromine (Br y ) (e.g.…”

Section: Introductionmentioning

confidence: 99%