Effective radiative forcing from emissions of reactive gases and aerosols – a multi-model comparison
oleh: G. D. Thornhill, W. J. Collins, R. J. Kramer, R. J. Kramer, D. Olivié, R. B. Skeie, F. M. O'Connor, N. L. Abraham, N. L. Abraham, R. Checa-Garcia, S. E. Bauer, M. Deushi, L. K. Emmons, P. M. Forster, L. W. Horowitz, B. Johnson, J. Keeble, J.-F. Lamarque, M. Michou, M. J. Mills, J. P. Mulcahy, G. Myhre, P. Nabat, V. Naik, N. Oshima, M. Schulz, C. J. Smith, C. J. Smith, T. Takemura, S. Tilmes, T. Wu, G. Zeng, J. Zhang
| Format: | Article |
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| Diterbitkan: | Copernicus Publications 2021-01-01 |
Deskripsi
<p>This paper quantifies the pre-industrial (1850) to present-day (2014) effective radiative forcing (ERF) of anthropogenic emissions of NO<span class="inline-formula"><sub><i>X</i></sub></span>, volatile organic compounds (VOCs; including CO), SO<span class="inline-formula"><sub>2</sub></span>, NH<span class="inline-formula"><sub>3</sub></span>, black carbon, organic carbon, and concentrations of methane, N<span class="inline-formula"><sub>2</sub></span>O and ozone-depleting halocarbons, using CMIP6 models. Concentration and emission changes of reactive species can cause multiple changes in the composition of radiatively active species: tropospheric ozone, stratospheric ozone, stratospheric water vapour, secondary inorganic and organic aerosol, and methane. Where possible we break down the ERFs from each emitted species into the contributions from the composition changes. The ERFs are calculated for each of the models that participated in the AerChemMIP experiments as part of the CMIP6 project, where the relevant model output was available.</p> <p><span id="page854"/>The 1850 to 2014 multi-model mean ERFs (<span class="inline-formula">±</span> standard deviations) are <span class="inline-formula">−1.03</span> <span class="inline-formula">±</span> 0.37 W m<span class="inline-formula"><sup>−2</sup></span> for SO<span class="inline-formula"><sub>2</sub></span> emissions, <span class="inline-formula">−0.2</span>5 <span class="inline-formula">±</span> 0.09 W m<span class="inline-formula"><sup>−2</sup></span> for organic carbon (OC), 0.15 <span class="inline-formula">±</span> 0.17 W m<span class="inline-formula"><sup>−2</sup></span> for black carbon (BC) and <span class="inline-formula">−0.07</span> <span class="inline-formula">±</span> 0.01 W m<span class="inline-formula"><sup>−2</sup></span> for NH<span class="inline-formula"><sub>3</sub></span>. For the combined aerosols (in the piClim-aer experiment) it is <span class="inline-formula">−1.01</span> <span class="inline-formula">±</span> 0.25 W m<span class="inline-formula"><sup>−2</sup></span>. The multi-model means for the reactive well-mixed greenhouse gases (including any effects on ozone and aerosol chemistry) are 0.67 <span class="inline-formula">±</span> 0.17 W m<span class="inline-formula"><sup>−2</sup></span> for methane (CH<span class="inline-formula"><sub>4</sub></span>), 0.26 <span class="inline-formula">±</span> 0.07 W m<span class="inline-formula"><sup>−2</sup></span> for nitrous oxide (N<span class="inline-formula"><sub>2</sub></span>O) and 0.12 <span class="inline-formula">±</span> 0.2 W m<span class="inline-formula"><sup>−2</sup></span> for ozone-depleting halocarbons (HC). Emissions of the ozone precursors nitrogen oxides (NO<span class="inline-formula"><sub><i>x</i></sub></span>), volatile organic compounds and both together (O<span class="inline-formula"><sub>3</sub></span>) lead to ERFs of 0.14 <span class="inline-formula">±</span> 0.13, 0.09 <span class="inline-formula">±</span> 0.14 and 0.20 <span class="inline-formula">±</span> 0.07 W m<span class="inline-formula"><sup>−2</sup></span> respectively. The differences in ERFs calculated for the different models reflect differences in the complexity of their aerosol and chemistry schemes, especially in the case of methane where tropospheric chemistry captures increased forcing from ozone production.</p>