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1. Preindustrial to present-day changes in tropospheric hydroxyl radical and methane lifetime from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

Author

Naik, V., Voulgarakis, A., Fiore, A. M, Horowitz, L. W, Lamarque, J.-F., Lin, M., Prather, M. J, Young, P. J, Bergmann, D., Cameron-Smith, P. J, Cionni, I., Collins, W. J, Dalsoren, S. B, Doherty, R., Eyring, V., Faluvegi, G., Folberth, G. A, Josse, B., Lee, Y. H, MacKenzie, I. A, Nagashima, T., van Noije, T. P. C, Plummer, D. A, Righi, M., Rumbold, S. T, Skeie, R., Shindell, D. T, Stevenson, D. S, Strode, S., Sudo, K., Szopa, S., and Zeng, G.

Subjects
atmospheric chemistry, climate change, climate modeling, hydroxyl radical, methane, photolysis, radiative forcing, stratosphere, troposphere
Abstract

We have analysed time-slice simulations from 17 global models, participating in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP), to explore changes in present-day (2000) hydroxyl radical (OH) concentration and methane (CH4) lifetime relative to preindustrial times (1850) and to 1980. A comparison of modeled and observation-derived methane and methyl chloroform lifetimes suggests that the present-day global multi-model mean OH concentration is overestimated by 5 to 10% but is within the range of uncertainties. The models consistently simulate higher OH concentrations in the Northern Hemisphere (NH) compared with the Southern Hemisphere (SH) for the present-day (2000; inter-hemispheric ratios of 1.13 to 1.42), in contrast to observation-based approaches which generally indicate higher OH in the SH although uncertainties are large. Evaluation of simulated carbon monoxide (CO) concentrations, the primary sink for OH, against ground-based and satellite observations suggests low biases in the NH that may contribute to the high north–south OH asymmetry in the models. The models vary widely in their regional distribution of present-day OH concentrations (up to 34%). Despite large regional changes, the multi-model global mean (mass-weighted) OH concentration changes little over the past 150 yr, due to concurrent increases in factors that enhance OH (humidity, tropospheric ozone, nitrogen oxide (NOx) emissions, and UV radiation due to decreases in stratospheric ozone), compensated by increases in OH sinks (methane abundance, carbon monoxide and non-methane volatile organic carbon (NMVOC) emissions). The large inter-model diversity in the sign and magnitude of preindustrial to present-day OH changes (ranging from a decrease of 12.7% to an increase of 14.6%) indicate that uncertainty remains in our understanding of the long-term trends in OH and methane lifetime. We show that this diversity is largely explained by the different ratio of the change in global mean tropospheric CO and NOx burdens (ΔCO/ΔNOx, approximately represents changes in OH sinks versus changes in OH sources) in the models, pointing to a need for better constraints on natural precursor emissions and on the chemical mechanisms in the current generation of chemistry-climate models. For the 1980 to 2000 period, we find that climate warming and a slight increase in mean OH (3.5 ± 2.2%) leads to a 4.3 ± 1.9% decrease in the methane lifetime. Analysing sensitivity simulations performed by 10 models, we find that preindustrial to present-day climate change decreased the methane lifetime by about four months, representing a negative feedback on the climate system. Further, we analysed attribution experiments performed by a subset of models relative to 2000 conditions with only one precursor at a time set to 1860 levels. We find that global mean OH increased by 46.4 ± 12.2% in response to preindustrial to present-day anthropogenic NOx emission increases, and decreased by 17.3 ± 2.3%, 7.6 ± 1.5%, and 3.1 ± 3.0% due to methane burden, and anthropogenic CO, and NMVOC emissions increases, respectively.

Published
2013

2. Analysis of present day and future OH and methane lifetime in the ACCMIP simulations

Author

Voulgarakis, A., Naik, V., Lamarque, J.-F., Shindell, D. T, Young, P. J, Prather, M. J, Wild, O., Field, R. D, Bergmann, D., Cameron-Smith, P., Cionni, I., Collins, W. J, Dalsøren, S. B, Doherty, R. M, Eyring, V., Faluvegi, G., Folberth, G. A, Horowitz, L. W, Josse, B., MacKenzie, I. A, Nagashima, T., Plummer, D. A, Righi, M., Rumbold, S. T, Stevenson, D. S, Strode, S. A, Sudo, K., Szopa, S., and Zeng, G.

Subjects
atmospheric chemistry, climate change, climate modeling, hydroxyl radical, methane, photolysis, radiative forcing, stratosphere, troposphere
Abstract

Results from simulations performed for the Atmospheric Chemistry and Climate Modeling Intercomparison Project (ACCMIP) are analysed to examine how OH and methane lifetime may change from present day to the future, under different climate and emissions scenarios. Present day (2000) mean tropospheric chemical lifetime derived from the ACCMIP multi-model mean is 9.8 ± 1.6 yr (9.3 ± 0.9 yr when only including selected models), lower than a recent observationally-based estimate, but with a similar range to previous multi-model estimates. Future model projections are based on the four Representative Concentration Pathways (RCPs), and the results also exhibit a large range. Decreases in global methane lifetime of 4.5 ± 9.1% are simulated for the scenario with lowest radiative forcing by 2100 (RCP 2.6), while increases of 8.5 ± 10.4% are simulated for the scenario with highest radiative forcing (RCP 8.5). In this scenario, the key driver of the evolution of OH and methane lifetime is methane itself, since its concentration more than doubles by 2100 and it consumes much of the OH that exists in the troposphere. Stratospheric ozone recovery, which drives tropospheric OH decreases through photolysis modifications, also plays a partial role. In the other scenarios, where methane changes are less drastic, the interplay between various competing drivers leads to smaller and more diverse OH and methane lifetime responses, which are difficult to attribute. For all scenarios, regional OH changes are even more variable, with the most robust feature being the large decreases over the remote oceans in RCP8.5. Through a regression analysis, we suggest that differences in emissions of non-methane volatile organic compounds and in the simulation of photolysis rates may be the main factors causing the differences in simulated present day OH and methane lifetime. Diversity in predicted changes between present day and future OH was found to be associated more strongly with differences in modelled temperature and stratospheric ozone changes. Finally, through perturbation experiments we calculated an OH feedback factor (F) of 1.24 from present day conditions (1.50 from 2100 RCP8.5 conditions) and a climate feedback on methane lifetime of 0.33 ± 0.13 yr K−1, on average. Models that did not include interactive stratospheric ozone effects on photolysis showed a stronger sensitivity to climate, as they did not account for negative effects of climate-driven stratospheric ozone recovery on tropospheric OH, which would have partly offset the overall OH/methane lifetime response to climate change.

Published
2013

3. Tropospheric Ozone Changes, Radiative Forcing and Attribution to Emissions in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

Author

Stevenson, D.S, Young, P.J, Naik, V, Lamarque, J.-F, Shindell, D. T, Voulgarakis, A, Skeie, R. B, Dalsoren, S. B, Myhre, G, Berntsen, T. K, Folberth, G. A, Rumbold, S. T, Collins, W. J, MacKenzie, I. A, Doherty, R. M, Zeng, G, vanNoije, T. P. C, Strunk, A, Bergmann, D, Cameron-Smith, P, Plummer, D. A, Strode, S. A, Horowitz, L, Lee, Y. H, Szopa, S, Sudo, K, Nagashima, T, Josse, B, Cionni, I, Righi, M, Eyring, V, Conley, A, Bowman, K. W, Wild, O, and Archibald, A

Subjects
Meteorology And Climatology
Abstract

Ozone (O3) from 17 atmospheric chemistry models taking part in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) has been used to calculate tropospheric ozone radiative forcings (RFs). All models applied a common set of anthropogenic emissions, which are better constrained for the present-day than the past. Future anthropogenic emissions follow the four Representative Concentration Pathway (RCP) scenarios, which define a relatively narrow range of possible air pollution emissions. We calculate a value for the pre-industrial (1750) to present-day (2010) tropospheric ozone RF of 410 mW m−2. The model range of pre-industrial to present-day changes in O3 produces a spread (+/-1 standard deviation) in RFs of +/-17%. Three different radiation schemes were used - we find differences in RFs between schemes (for the same ozone fields) of +/-10 percent. Applying two different tropopause definitions gives differences in RFs of +/-3 percent. Given additional (unquantified) uncertainties associated with emissions, climate-chemistry interactions and land-use change, we estimate an overall uncertainty of +/-30 percent for the tropospheric ozone RF. Experiments carried out by a subset of six models attribute tropospheric ozone RF to increased emissions of methane (44+/-12 percent), nitrogen oxides (31 +/- 9 percent), carbon monoxide (15 +/- 3 percent) and non-methane volatile organic compounds (9 +/- 2 percent); earlier studies attributed more of the tropospheric ozone RF to methane and less to nitrogen oxides. Normalising RFs to changes in tropospheric column ozone, we find a global mean normalised RF of 42 mW m(−2) DU(−1), a value similar to previous work. Using normalised RFs and future tropospheric column ozone projections we calculate future tropospheric ozone RFs (mW m(−2); relative to 1750) for the four future scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) of 350, 420, 370 and 460 (in 2030), and 200, 300, 280 and 600 (in 2100). Models show some coherent responses of ozone to climate change: decreases in the tropical lower troposphere, associated with increases in water vapour; and increases in the sub-tropical to mid-latitude upper troposphere, associated with increases in lightning and stratosphere-to-troposphere transport. Climate change has relatively small impacts on global mean tropospheric ozone RF.

Published
2013
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4. Radiative Forcing in the ACCMIP Historical and Future Climate Simulations

Author

Shindell, Drew Todd, Lamarque, J.-F, Schulz, M, Flanner, M, Jiao, C, Chin, M, Young, P. J, Lee, Y. H, Rotstayn, L, Mahowald, N, Milly, G, Faluvegi, G, Balkanski, Y, Collins, W. J, Conley, A. J, Dalsoren, S, Easter, R, Ghan, S, Horowitz, L, Liu, X, Myhre, G, Nagashima, T, Naik, V, Rumbold, S. T, Skeie, R, and Voulgarakis, A

Subjects
Earth Resources And Remote Sensing
Abstract

A primary goal of the Atmospheric Chemistry and Climate Model IntercomparisonProject (ACCMIP) was to characterize the short-lived drivers of preindustrial to 2100climate change in the current generation of climate models. Here we evaluate historicaland 5 future radiative forcing in the 10 ACCMIP models that included aerosols, 8 of whichalso participated in the Coupled Model Intercomparison Project phase 5 (CMIP5).The models generally reproduce present-day climatological total aerosol opticaldepth (AOD) relatively well. components to this total, however, and most appear to underestimate AOD over East10 Asia. The models generally capture 1980-2000 AOD trends fairly well, though theyunderpredict AOD increases over the YellowEastern Sea. They appear to strongly underestimate absorbing AOD, especially in East Asia, South and Southeast Asia, SouthAmerica and Southern Hemisphere Africa.We examined both the conventional direct radiative forcing at the tropopause (RF) and the forcing including rapid adjustments (adjusted forcing AF, including direct andindirect effects). The models calculated all aerosol all-sky 1850 to 2000 global meanannual average RF ranges from 0.06 to 0.49 W m(sup -2), with a mean of 0.26 W m(sup -2) and a median of 0.27 W m(sup -2. Adjusting for missing aerosol components in some modelsbrings the range to 0.12 to 0.62W m(sup -2), with a mean of 0.39W m(sup -2). Screen20ing the models based on their ability to capture spatial patterns and magnitudes ofAOD and AOD trends yields a quality-controlled mean of 0.42W m(sup -2) and range of0.33 to 0.50 W m(sup -2) (accounting for missing components). The CMIP5 subset of ACCMIPmodels spans 0.06 to 0.49W m(sup -2), suggesting some CMIP5 simulations likelyhave too little aerosol RF. A substantial, but not well quantified, contribution to histori25cal aerosol RF may come from climate feedbacks (35 to 58). The mean aerosol AF during this period is 1.12W m(sup -2) (median value 1.16W m(sup -2), range 0.72 to1.44W m(sup -2), indicating that adjustments to aerosols, which include cloud, water vaporand temperature, lead to stronger forcing than the aerosol direct RF.

Published
2013
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5. Evaluation of preindustrial to present-day black carbon and its albedo forcing from Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

Author

Lee, Y. H, Lamarque, J.-F, Flanner, M. G, Jiao, C, Shindell, D. T, Bernsten, T, Bisiaux, M. M, Cao, J, Collins, W. J, Curran, M, Edwards, R, Faluvegi, G, Ghan, S, Horowitz, L. W, McConnell, J. R, Ming, J, Myhre, G, Nagashima, T, Naik, V, Rumbold, S. T, Skeie, R. B, Sudo, K, Takemura, T, Thevenon, F, Xu, B, and Yoon, J.-H

Subjects
Meteorology And Climatology
Abstract

As part of the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP), we evaluate the historical black carbon (BC) aerosols simulated by 8 ACCMIP models against observations including 12 ice core records, long-term surface mass concentrations, and recent Arctic BC snowpack measurements. We also estimate BC albedo forcing by performing additional simulations using offline models with prescribed meteorology from 1996-2000. We evaluate the vertical profile of BC snow concentrations from these offline simulations using the recent BC snowpack measurements. Despite using the same BC emissions, the global BC burden differs by approximately a factor of 3 among models due to differences in aerosol removal parameterizations and simulated meteorology: 34 Gg to 103 Gg in 1850 and 82 Gg to 315 Gg in 2000. However, the global BC burden from preindustrial to present-day increases by 2.5-3 times with little variation among models, roughly matching the 2.5-fold increase in total BC emissions during the same period.We find a large divergence among models at both Northern Hemisphere (NH) and Southern Hemisphere (SH) high latitude regions for BC burden and at SH high latitude regions for deposition fluxes. The ACCMIP simulations match the observed BC surface mass concentrations well in Europe and North America except at Ispra. However, the models fail to predict the Arctic BC seasonality due to severe underestimations during winter and spring. The simulated vertically resolved BC snow concentrations are, on average, within a factor of 2-3 of the BC snowpack measurements except for Greenland and the Arctic Ocean. For the ice core evaluation, models tend to adequately capture both the observed temporal trends and the magnitudes at Greenland sites. However, models fail to predict the decreasing trend of BC depositions/ice core concentrations from the 1950s to the 1970s in most Tibetan Plateau ice cores. The distinct temporal trend at the Tibetan Plateau ice cores indicates a strong influence from Western Europe, but the modeled BC increases in that period are consistent with the emission changes in Eastern Europe, the Middle East, South and East Asia. At the Alps site, the simulated BC suggests a strong influence from Europe, which agrees with the Alps ice core observations. At Zuoqiupu on the Tibetan Plateau, models successfully simulate the higher BC concentrations observed during the non-monsoon season compared to the monsoon season but overpredict BC in both seasons. Despite a large divergence in BC deposition at two Antarctic ice core sites, some models with a BC lifetime of less than 7 days are able to capture the observed concentrations. In 2000 relative to 1850, globally and annually averaged BC surface albedo forcing from the offline simulations ranges from 0.014 to 0.019Wm−2 among the ACCMIP models. Comparing offline and online BC albedo forcings computed by some of the same models, we find that the global annual mean can vary by up to a factor of two because of different aerosol models or different BC-snow parameterizations and snow cover. The spatial distributions of the offline BC albedo forcing in 2000 show especially high BC forcing (i.e., over 0.1W/sq. m) over Manchuria, Karakoram, and most of the Former USSR. Models predict the highest global annual mean BC forcing in 1980 rather than 2000, mostly driven by the high fossil fuel and biofuel emissions in the Former USSR in 1980.

Published
2013
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6. The Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP): Overview and Description of Models, Simulations and Climate Diagnostics

Author

Lamarque, J.-F, Shindell, D. T, Naik, V, Plummer, D, Josse, B, Righi, M, Rumbold, S. T, Schulz, M, Skeie, R. B, Strode, S, Young, P. J, Cionni, I, Dalsoren, S, Eyring, V, Bergmann, D, Cameron-Smith, P, Collins, W. J, Doherty, R, Faluvegi, G, Folberth, G, Ghan, S. J, Horowitz, L. W, Lee, Y. H, MacKenzie, I. A, and Nagashima, T

Subjects
Meteorology And Climatology
Abstract

The Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) consists of a series of time slice experiments targeting the long-term changes in atmospheric composition between 1850 and 2100, with the goal of documenting composition changes and the associated radiative forcing. In this overview paper, we introduce the ACCMIP activity, the various simulations performed (with a requested set of 14) and the associated model output. The 16 ACCMIP models have a wide range of horizontal and vertical resolutions, vertical extent, chemistry schemes and interaction with radiation and clouds. While anthropogenic and biomass burning emissions were specified for all time slices in the ACCMIP protocol, it is found that the natural emissions are responsible for a significant range across models, mostly in the case of ozone precursors. The analysis of selected present-day climate diagnostics (precipitation, temperature, specific humidity and zonal wind) reveals biases consistent with state-of-the-art climate models. The model-to- model comparison of changes in temperature, specific humidity and zonal wind between 1850 and 2000 and between 2000 and 2100 indicates mostly consistent results. However, models that are clear outliers are different enough from the other models to significantly affect their simulation of atmospheric chemistry.

Published
2013
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7. Spin‐up of UK Earth System Model 1 (UKESM1) for CMIP6

Author

Yool, A., primary, Palmiéri, J., additional, Jones, C. G., additional, Sellar, A. A., additional, de Mora, L., additional, Kuhlbrodt, T., additional, Popova, E. E., additional, Mulcahy, J. P., additional, Wiltshire, A., additional, Rumbold, S. T., additional, Stringer, M., additional, Hill, R. S. R., additional, Tang, Y., additional, Walton, J., additional, Blaker, A., additional, Nurser, A. J. G., additional, Coward, A. C., additional, Hirschi, J., additional, Woodward, S., additional, Kelley, D. I., additional, Ellis, R., additional, and Rumbold‐Jones, S., additional

Published
2020
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8. Improved Aerosol Processes and Effective Radiative Forcing in HadGEM3 and UKESM1

Author

Mulcahy, J. P., primary, Jones, C., additional, Sellar, A., additional, Johnson, B., additional, Boutle, I. A., additional, Jones, A., additional, Andrews, T., additional, Rumbold, S. T., additional, Mollard, J., additional, Bellouin, N., additional, Johnson, C. E., additional, Williams, K. D., additional, Grosvenor, D. P., additional, and McCoy, D. T., additional

Published
2018
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9. Evaluating the CLimate and Air Quality ImPacts of Short-livEd Pollutants (ECLIPSE)

Author

Stohl, A., Aamaas, B., Amann, M., Baker, L.H., Bellouin, N., Berntsen, T.K., Boucher, O., Cherian, R., Collins, W., Daskalakis, N., Dusinska, M., Eck-hardt, S., Fuglestvedt, J. S., Harju, M., Heyes, C., Hodnebrog, Ø., Hao, J., Im, Ulas, Kanakidou, M., Klimont, Z., Kupiainen, K., Law, K. S., Lund, M. T., Maas, R., MacIntosh, C. R., Myhre, G., Myriokefalitakis, S., Olivié, D., Quaas, J., Quennehen, B., Raut, J.-C., Rumbold, S. T., Samset, B.H., Schulz, M., Seland, Ø., Shine, K. P., Skeie, R. B., Wang, S., Yttri, K. E., and Zhu, T.

Published
2015

10. Current model capabilities for simulating black carbon and sulfate concentrations in the Arctic atmosphere: a multi-model evaluation using a comprehensive measurement data set

Author

Eckhardt, S., Quennehen, B., Olivié, D. J. L., Berntsen, T. K., Cherian, R., Christensen, J. H., Collins, W., Crepinsek, S., Daskalakis, N., Flanner, M., Herber, A., Heyes, C., Hodnebrog, Ø., Huang, L., Kanakidou, M., Klimont, Z., Langner, J., Law, K. S., Lund, M. T., Mahmood, R., Massling, A., Myriokefalitakis, S., Nielsen, I. E., Nøjgaard, J. K., Quaas, J., Quinn, P. K., Raut, J.-C., Rumbold, S. T., Schulz, M., Sharma, S., Skeie, R. B., Skov, H., Uttal, T., von Salzen, K., Stohl, A., Norwegian Institute for Air Research (NILU), TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Norwegian Meteorological Institute [Oslo] (MET), Center for International Climate and Environmental Research [Oslo] (CICERO), University of Oslo (UiO), Leipziger Institut für Meteorologie (LIM), Universität Leipzig [Leipzig], Department of Environmental Science [Roskilde] (ENVS), Aarhus University [Aarhus], University of Reading (UOR), Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office [Exeter], Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado [Boulder]-National Oceanic and Atmospheric Administration (NOAA), NOAA Earth System Research Laboratory (ESRL), National Oceanic and Atmospheric Administration (NOAA), Environmental Chemical Processes Laboratory [Heraklion] (ECPL), Department of Chemistry [Heraklion], University of Crete [Heraklion] (UOC)-University of Crete [Heraklion] (UOC), Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), International Institute for Applied Systems Analysis [Laxenburg] (IIASA), Climate Research Division [Toronto], Environment and Climate Change Canada, Swedish Meteorological and Hydrological Institute (SMHI), School of Earth and Ocean Sciences [Victoria] (SEOS), University of Victoria [Canada] (UVIC), COMSATS Institute of Information Technology [Islamabad] (CIIT), Institute of Chemical Engineering Sciences - Hellas [Crete] (ICE-HT), Foundation for Research and Technology - Hellas (FORTH), NOAA Pacific Marine Environmental Laboratory [Seattle] (PMEL), Canadian Centre for Climate Modelling and Analysis (CCCma), and Universität Leipzig

Subjects
lcsh:Chemistry, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Zeppelinobservatoriet, lcsh:QD1-999, [SDE]Environmental Sciences, Miljövetenskap, lcsh:Physics, lcsh:QC1-999, Environmental Sciences
Abstract

International audience; The concentrations of sulfate, black carbon (BC) and other aerosols in the Arctic are characterized by high values in late winter and spring (so-called Arctic Haze) and low values in summer. Models have long been struggling to capture this seasonality and especially the high concentrations associated with Arctic Haze. In this study, we evaluate sulfate and BC concentrations from eleven different models driven with the same emission inventory against a comprehensive pan-Arctic measurement data set over a time period of two years (2008–2009). The set of models consisted of one Lagrangian particle dispersion model, four chemistry-transport models (CTMs), one atmospheric chemistry-weather forecast model and five chemistry-climate models (CCMs), of which two were nudged to meteorological analyses and three were running freely. The measurement data set consisted of surface measurements of equivalent BC (eBC) from five stations (Alert, Barrow, Pallas, Tiksi and Zeppelin), elemental carbon (EC) from Station Nord and Alert and aircraft measurements of refractory BC (rBC) from six different campaigns. We find that the models generally captured the measured eBC/rBC and sulfate concentrations quite well, compared to past comparisons. However, the aerosol seasonality at the surface is still too weak in most models. Concentrations of eBC and sulfate averaged over three surface sites are underestimated in winter/spring in all but one model (model means for January-March underestimated by 59 and 37% for BC and sulfate, respectively), whereas concentrations in summer are overestimated in the model mean (by 88 and 44% for July–September), but with over- as well as underestimates present in individual models. The most pronounced eBC underestimates, not included in the above multi-site average, are found for the station Tiksi in Siberia where the measured annual mean eBC concentration is three times higher than the average annual mean for all other stations. This suggests an underestimate of BC sources in Russia in the emission inventory used. Based on the campaign data, biomass burning was identified as another cause of the modelling problems. For sulfate, very large differences were found in the model ensemble, with an apparent anti-correlation between modeled surface concentrations and total atmospheric columns. There is a strong correlation between observed sulfate and eBC concentrations with consistent sulfate/eBC slopes found for all Arctic stations, indicating that the sources contributing to sulfate and BC are similar throughout the Arctic and that the aerosols are internally mixed and undergo similar removal. However, only three models reproduced this finding, whereas sulfate and BC are weakly correlated in the other models. Overall, no class of models (e.g., CTMs, CCMs) performed better than the others and differences are independent of model resolution.

Published
2015

11. Multi-model evaluation of short-lived pollutant distributions over east Asia during summer 2008

Author

Quennehen, B., Raut, J.-C., Law, K. S., Daskalakis, N., Ancellet, G., Clerbaux, C., Kim, S.-W., Lund, M. T., Myhre, G., Olivié, D. J. L., Safieddine, S., Skeie, R. B., Thomas, J. L., Tsyro, S., Bazureau, A., Bellouin, N., Hu, M., Kanakidou, M., Klimont, Z., Kupiainen, K., Myriokefalitakis, S., Quaas, J., Rumbold, S. T., Schulz, M., Cherian, R., Shimizu, A., Wang, J., Yoon, S.-C., Zhu, T., Quennehen, B., Raut, J.-C., Law, K. S., Daskalakis, N., Ancellet, G., Clerbaux, C., Kim, S.-W., Lund, M. T., Myhre, G., Olivié, D. J. L., Safieddine, S., Skeie, R. B., Thomas, J. L., Tsyro, S., Bazureau, A., Bellouin, N., Hu, M., Kanakidou, M., Klimont, Z., Kupiainen, K., Myriokefalitakis, S., Quaas, J., Rumbold, S. T., Schulz, M., Cherian, R., Shimizu, A., Wang, J., Yoon, S.-C., and Zhu, T.

Abstract

The ability of seven state-of-the-art chemistry–aerosol models to reproduce distributions of tropospheric ozone and its precursors, as well as aerosols over eastern Asia in summer 2008, is evaluated. The study focuses on the performance of models used to assess impacts of pollutants on climate and air quality as part of the EU ECLIPSE project. Models, run using the same ECLIPSE emissions, are compared over different spatial scales to in situ surface, vertical profiles and satellite data. Several rather clear biases are found between model results and observations, including overestimation of ozone at rural locations downwind of the main emission regions in China, as well as downwind over the Pacific. Several models produce too much ozone over polluted regions, which is then transported downwind. Analysis points to different factors related to the ability of models to simulate VOC-limited regimes over polluted regions and NOx limited regimes downwind. This may also be linked to biases compared to satellite NO2, indicating overestimation of NO2 over and to the north of the northern China Plain emission region. On the other hand, model NO2 is too low to the south and west of this region and over South Korea/Japan. Overestimation of ozone is linked to systematic underestimation of CO particularly at rural sites and downwind of the main Chinese emission regions. This is likely to be due to enhanced destruction of CO by OH. Overestimation of Asian ozone and its transport downwind implies that radiative forcing from this source may be overestimated. Model-observation discrepancies over Beijing do not appear to be due to emission controls linked to the Olympic Games in summer 2008. With regard to aerosols, most models reproduce the satellite-derived AOD patterns over eastern China. Our study nevertheless reveals an overestimation of ECLIPSE model mean surface BC and sulphate aerosols in urban China in summer 2008. The effect of the short-term emission mitigation in Beijing

Published
2016

12. Multi-model evaluation of short-lived pollutant distributions over east Asia during summer 2008

Author

Quennehen, B., primary, Raut, J.-C., additional, Law, K. S., additional, Daskalakis, N., additional, Ancellet, G., additional, Clerbaux, C., additional, Kim, S.-W., additional, Lund, M. T., additional, Myhre, G., additional, Olivié, D. J. L., additional, Safieddine, S., additional, Skeie, R. B., additional, Thomas, J. L., additional, Tsyro, S., additional, Bazureau, A., additional, Bellouin, N., additional, Hu, M., additional, Kanakidou, M., additional, Klimont, Z., additional, Kupiainen, K., additional, Myriokefalitakis, S., additional, Quaas, J., additional, Rumbold, S. T., additional, Schulz, M., additional, Cherian, R., additional, Shimizu, A., additional, Wang, J., additional, Yoon, S.-C., additional, and Zhu, T., additional

Published
2016
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13. Evaluating the climate and air quality impacts of short-lived pollutants

Author

Stohl, A., primary, Aamaas, B., additional, Amann, M., additional, Baker, L. H., additional, Bellouin, N., additional, Berntsen, T. K., additional, Boucher, O., additional, Cherian, R., additional, Collins, W., additional, Daskalakis, N., additional, Dusinska, M., additional, Eckhardt, S., additional, Fuglestvedt, J. S., additional, Harju, M., additional, Heyes, C., additional, Hodnebrog, Ø., additional, Hao, J., additional, Im, U., additional, Kanakidou, M., additional, Klimont, Z., additional, Kupiainen, K., additional, Law, K. S., additional, Lund, M. T., additional, Maas, R., additional, MacIntosh, C. R., additional, Myhre, G., additional, Myriokefalitakis, S., additional, Olivié, D., additional, Quaas, J., additional, Quennehen, B., additional, Raut, J.-C., additional, Rumbold, S. T., additional, Samset, B. H., additional, Schulz, M., additional, Seland, Ø., additional, Shine, K. P., additional, Skeie, R. B., additional, Wang, S., additional, Yttri, K. E., additional, and Zhu, T., additional

Published
2015
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14. Multi-model evaluation of short-lived pollutant distributions over East Asia during summer 2008

Author

Quennehen, B., primary, Raut, J.-C., additional, Law, K. S., additional, Ancellet, G., additional, Clerbaux, C., additional, Kim, S.-W., additional, Lund, M. T., additional, Myhre, G., additional, Olivié, D. J. L., additional, Safieddine, S., additional, Skeie, R. B., additional, Thomas, J. L., additional, Tsyro, S., additional, Bazureau, A., additional, Bellouin, N., additional, Daskalakis, N., additional, Hu, M., additional, Kanakidou, M., additional, Klimont, Z., additional, Kupiainen, K., additional, Myriokefalitakis, S., additional, Quaas, J., additional, Rumbold, S. T., additional, Schulz, M., additional, Cherian, R., additional, Shimizu, A., additional, Wang, J., additional, Yoon, S.-C., additional, and Zhu, T., additional

Published
2015
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15. Current model capabilities for simulating black carbon and sulfate concentrations in the Arctic atmosphere: a multi-model evaluation using a comprehensive measurement data set

Author

Eckhardt, S., primary, Quennehen, B., additional, Olivié, D. J. L., additional, Berntsen, T. K., additional, Cherian, R., additional, Christensen, J. H., additional, Collins, W., additional, Crepinsek, S., additional, Daskalakis, N., additional, Flanner, M., additional, Herber, A., additional, Heyes, C., additional, Hodnebrog, Ø., additional, Huang, L., additional, Kanakidou, M., additional, Klimont, Z., additional, Langner, J., additional, Law, K. S., additional, Massling, A., additional, Myriokefalitakis, S., additional, Nielsen, I. E., additional, Nøjgaard, J. K., additional, Quaas, J., additional, Quinn, P. K., additional, Raut, J.-C., additional, Rumbold, S. T., additional, Schulz, M., additional, Skeie, R. B., additional, Skov, H., additional, Lund, M. T., additional, Uttal, T., additional, von Salzen, K., additional, Mahmood, R., additional, and Stohl, A., additional

Published
2015
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16. Corrigendum to "Evaluation of preindustrial to present-day black carbon and its albedo forcing from Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)" published in Atmos. Chem. Phys., 13, 2607–2634, 2013

Author

Lee, Y. H., primary, Lamarque, J.-F., additional, Flanner, M. G., additional, Jiao, C., additional, Shindell, D. T., additional, Berntsen, T., additional, Bisiaux, M. M., additional, Cao, J., additional, Collins, W. J., additional, Curran, M., additional, Edwards, R., additional, Faluvegi, G., additional, Ghan, S., additional, Horowitz, L. W., additional, McConnell, J. R., additional, Ming, J., additional, Myhre, G., additional, Nagashima, T., additional, Naik, V., additional, Rumbold, S. T., additional, Skeie, R. B., additional, Sudo, K., additional, Takemura, T., additional, Thevenon, F., additional, Xu, B., additional, and Yoon, J.-H., additional

Published
2013
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17. Corrigendum to "Pre-industrial to end 21st century projections of tropospheric ozone from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)" published in Atmos. Chem. Phys., 13, 2063–2090, 2013

Author

Young, P. J., primary, Archibald, A. T., additional, Bowman, K. W., additional, Lamarque, J.-F., additional, Naik, V., additional, Stevenson, D. S., additional, Tilmes, S., additional, Voulgarakis, A., additional, Wild, O., additional, Bergmann, D., additional, Cameron-Smith, P., additional, Cionni, I., additional, Collins, W. J., additional, Dalsøren, S. B., additional, Doherty, R. M., additional, Eyring, V., additional, Faluvegi, G., additional, Horowitz, L. W., additional, Josse, B., additional, Lee, Y. H., additional, MacKenzie, I. A., additional, Nagashima, T., additional, Plummer, D. A., additional, Righi, M., additional, Rumbold, S. T., additional, Skeie, R. B., additional, Shindell, D. T., additional, Strode, S. A., additional, Sudo, K., additional, Szopa, S., additional, and Zeng, G., additional

Published
2013
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18. Evaluation of ACCMIP outgoing longwave radiation from tropospheric ozone using TES satellite observations

Author

Bowman, K. W., primary, Shindell, D. T., additional, Worden, H. M., additional, Lamarque, J.F., additional, Young, P. J., additional, Stevenson, D. S., additional, Qu, Z., additional, de la Torre, M., additional, Bergmann, D., additional, Cameron-Smith, P. J., additional, Collins, W. J., additional, Doherty, R., additional, Dalsøren, S. B., additional, Faluvegi, G., additional, Folberth, G., additional, Horowitz, L. W., additional, Josse, B. M., additional, Lee, Y. H., additional, MacKenzie, I. A., additional, Myhre, G., additional, Nagashima, T., additional, Naik, V., additional, Plummer, D. A., additional, Rumbold, S. T., additional, Skeie, R. B., additional, Strode, S. A., additional, Sudo, K., additional, Szopa, S., additional, Voulgarakis, A., additional, Zeng, G., additional, Kulawik, S. S., additional, Aghedo, A. M., additional, and Worden, J. R., additional

Published
2013
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19. Intercomparison of shortwave radiative transfer schemes in global aerosol modeling: results from the AeroCom Radiative Transfer Experiment

Author

Randles, C. A., primary, Kinne, S., additional, Myhre, G., additional, Schulz, M., additional, Stier, P., additional, Fischer, J., additional, Doppler, L., additional, Highwood, E., additional, Ryder, C., additional, Harris, B., additional, Huttunen, J., additional, Ma, Y., additional, Pinker, R. T., additional, Mayer, B., additional, Neubauer, D., additional, Hitzenberger, R., additional, Oreopoulos, L., additional, Lee, D., additional, Pitari, G., additional, Di Genova, G., additional, Quaas, J., additional, Rose, F. G., additional, Kato, S., additional, Rumbold, S. T., additional, Vardavas, I., additional, Hatzianastassiou, N., additional, Matsoukas, C., additional, Yu, H., additional, Zhang, F., additional, Zhang, H., additional, and Lu, P., additional

Published
2013
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20. Pre-industrial to end 21st century projections of tropospheric ozone from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

Author

Young, P. J., primary, Archibald, A. T., additional, Bowman, K. W., additional, Lamarque, J.-F., additional, Naik, V., additional, Stevenson, D. S., additional, Tilmes, S., additional, Voulgarakis, A., additional, Wild, O., additional, Bergmann, D., additional, Cameron-Smith, P., additional, Cionni, I., additional, Collins, W. J., additional, Dalsøren, S. B., additional, Doherty, R. M., additional, Eyring, V., additional, Faluvegi, G., additional, Horowitz, L. W., additional, Josse, B., additional, Lee, Y. H., additional, MacKenzie, I. A., additional, Nagashima, T., additional, Plummer, D. A., additional, Righi, M., additional, Rumbold, S. T., additional, Skeie, R. B., additional, Shindell, D. T., additional, Strode, S. A., additional, Sudo, K., additional, Szopa, S., additional, and Zeng, G., additional

Published
2013
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21. Intercomparison of shortwave radiative transfer schemes in global aerosol modeling: results from the AeroCom Radiative Transfer Experiment

Author

Randles, C. A., primary, Kinne, S., additional, Myhre, G., additional, Schulz, M., additional, Stier, P., additional, Fischer, J., additional, Doppler, L., additional, Highwood, E., additional, Ryder, C., additional, Harris, B., additional, Huttunen, J., additional, Ma, Y., additional, Pinker, R. T., additional, Mayer, B., additional, Neubauer, D., additional, Hitzenberger, R., additional, Oreopoulos, L., additional, Lee, D., additional, Pitari, G., additional, Di Genova, G., additional, Quaas, J., additional, Rose, Fred G., additional, Kato, S., additional, Rumbold, S. T., additional, Vardavas, I., additional, Hatzianastassiou, N., additional, Matsoukas, C., additional, Yu, H., additional, Zhang, F., additional, Zhang, H., additional, and Lu, P., additional

Published
2012
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22. Supplementary material to "Preindustrial to present day changes in tropospheric hydroxyl radical and methane lifetime from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)"

Author

Naik, V., primary, Voulgarakis, A., additional, Fiore, A. M., additional, Horowitz, L. W., additional, Lamarque, J.-F., additional, Lin, M., additional, Prather, M. J., additional, Young, P. J., additional, Bergmann, D., additional, Cameron-Smith, P. J., additional, Cionni, I., additional, Collins, W. J., additional, Dalsøren, S. B., additional, Doherty, R., additional, Eyring, V., additional, Faluvegi, G., additional, Folberth, G. A., additional, Josse, B., additional, Lee, Y. H., additional, MacKenzie, I. A., additional, Nagashima, T., additional, van Noije, T. P. C., additional, Plummer, D. A., additional, Righi, M., additional, Rumbold, S. T., additional, Skeie, R., additional, Shindell, D. T., additional, Stevenson, D. S., additional, Strode, S., additional, Sudo, K., additional, Szopa, S., additional, and Zeng, G., additional

Published
2012
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23. Preindustrial to present day changes in tropospheric hydroxyl radical and methane lifetime from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

Author

Naik, V., primary, Voulgarakis, A., additional, Fiore, A. M., additional, Horowitz, L. W., additional, Lamarque, J.-F., additional, Lin, M., additional, Prather, M. J., additional, Young, P. J., additional, Bergmann, D., additional, Cameron-Smith, P. J., additional, Cionni, I., additional, Collins, W. J., additional, Dalsøren, S. B., additional, Doherty, R., additional, Eyring, V., additional, Faluvegi, G., additional, Folberth, G. A., additional, Josse, B., additional, Lee, Y. H., additional, MacKenzie, I. A., additional, Nagashima, T., additional, van Noije, T. P. C., additional, Plummer, D. A., additional, Righi, M., additional, Rumbold, S. T., additional, Skeie, R., additional, Shindell, D. T., additional, Stevenson, D. S., additional, Strode, S., additional, Sudo, K., additional, Szopa, S., additional, and Zeng, G., additional

Published
2012
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24. Supplementary material to "Tropospheric ozone changes, radiative forcing and attribution to emissions in the Atmospheric Chemistry and Climate Model Inter-comparison Project (ACCMIP)"

Author

Stevenson, D. S., primary, Young, P. J., additional, Naik, V., additional, Lamarque, J.-F., additional, Shindell, D. T., additional, Voulgarakis, A., additional, Skeie, R. B., additional, Dalsoren, S. B., additional, Myhre, G., additional, Berntsen, T. K., additional, Folberth, G. A., additional, Rumbold, S. T., additional, Collins, W. J., additional, MacKenzie, I. A., additional, Doherty, R. M., additional, Zeng, G., additional, van Noije, T. P. C., additional, Strunk, A., additional, Bergmann, D., additional, Cameron-Smith, P., additional, Plummer, D. A., additional, Strode, S. A., additional, Horowitz, L., additional, Lee, Y. H., additional, Szopa, S., additional, Sudo, K., additional, Nagashima, T., additional, Josse, B., additional, Cionni, I., additional, Righi, M., additional, Eyring, V., additional, Conley, A., additional, Bowman, K. W., additional, and Wild, O., additional

Published
2012
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25. Tropospheric ozone changes, radiative forcing and attribution to emissions in the Atmospheric Chemistry and Climate Model Inter-comparison Project (ACCMIP)

Author

Stevenson, D. S., primary, Young, P. J., additional, Naik, V., additional, Lamarque, J.-F., additional, Shindell, D. T., additional, Voulgarakis, A., additional, Skeie, R. B., additional, Dalsoren, S. B., additional, Myhre, G., additional, Berntsen, T. K., additional, Folberth, G. A., additional, Rumbold, S. T., additional, Collins, W. J., additional, MacKenzie, I. A., additional, Doherty, R. M., additional, Zeng, G., additional, van Noije, T. P. C., additional, Strunk, A., additional, Bergmann, D., additional, Cameron-Smith, P., additional, Plummer, D. A., additional, Strode, S. A., additional, Horowitz, L., additional, Lee, Y. H., additional, Szopa, S., additional, Sudo, K., additional, Nagashima, T., additional, Josse, B., additional, Cionni, I., additional, Righi, M., additional, Eyring, V., additional, Conley, A., additional, Bowman, K. W., additional, and Wild, O., additional

Published
2012
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26. Analysis of present day and future OH and methane lifetime in the ACCMIP simulations

Author

Voulgarakis, A., primary, Naik, V., additional, Lamarque, J.-F., additional, Shindell, D. T., additional, Young, P. J., additional, Prather, M. J., additional, Wild, O., additional, Field, R. D., additional, Bergmann, D., additional, Cameron-Smith, P., additional, Cionni, I., additional, Collins, W. J., additional, Dalsøren, S. B., additional, Doherty, R. M., additional, Eyring, V., additional, Faluvegi, G., additional, Folberth, G. A., additional, Horowitz, L. W., additional, Josse, B., additional, McKenzie, I. A., additional, Nagashima, T., additional, Plummer, D. A., additional, Righi, M., additional, Rumbold, S. T., additional, Stevenson, D. S., additional, Strode, S. A., additional, Sudo, K., additional, Szopa, S., additional, and Zeng, G., additional

Published
2012
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27. Supplementary material to "Analysis of present day and future OH and methane lifetime in the ACCMIP simulations"

Author

Voulgarakis, A., primary, Naik, V., additional, Lamarque, J.-F., additional, Shindell, D. T., additional, Young, P. J., additional, Prather, M. J., additional, Wild, O., additional, Field, R. D., additional, Bergmann, D., additional, Cameron-Smith, P., additional, Cionni, I., additional, Collins, W. J., additional, Dalsøren, S. B., additional, Doherty, R. M., additional, Eyring, V., additional, Faluvegi, G., additional, Folberth, G. A., additional, Horowitz, L. W., additional, Josse, B., additional, McKenzie, I. A., additional, Nagashima, T., additional, Plummer, D. A., additional, Righi, M., additional, Rumbold, S. T., additional, Stevenson, D. S., additional, Strode, S. A., additional, Sudo, K., additional, Szopa, S., additional, and Zeng, G., additional

Published
2012
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28. Supplementary material to "Evaluation of preindustrial to present-day black carbon and its albedo forcing from ACCMIP (Atmospheric Chemistry and Climate Model Intercomparison Project)"

Author

Lee, Y. H., primary, Lamarque, J.-F., additional, Flanner, M. G., additional, Jiao, C., additional, Shindell, D. T., additional, Berntsen, T., additional, Bisiaux, M. M., additional, Cao, J., additional, Collins, W. J., additional, Curran, M., additional, Edwards, R., additional, Faluvegi, G., additional, Ghan, S., additional, Horowitz, L. W., additional, McConnell, J. R., additional, Myhre, G., additional, Nagashima, T., additional, Naik, V., additional, Rumbold, S. T., additional, Skeie, R. B., additional, Sudo, K., additional, Takemura, T., additional, and Thevenon, F., additional

Published
2012
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29. Evaluation of preindustrial to present-day black carbon and its albedo forcing from ACCMIP (Atmospheric Chemistry and Climate Model Intercomparison Project)

Author

Lee, Y. H., primary, Lamarque, J.-F., additional, Flanner, M. G., additional, Jiao, C., additional, Shindell, D. T., additional, Berntsen, T., additional, Bisiaux, M. M., additional, Cao, J., additional, Collins, W. J., additional, Curran, M., additional, Edwards, R., additional, Faluvegi, G., additional, Ghan, S., additional, Horowitz, L. W., additional, McConnell, J. R., additional, Myhre, G., additional, Nagashima, T., additional, Naik, V., additional, Rumbold, S. T., additional, Skeie, R. B., additional, Sudo, K., additional, Takemura, T., additional, and Thevenon, F., additional

Published
2012
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30. Supplementary material to "Pre-industrial to end 21st century projections of tropospheric ozone from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)"

Author

Young, P. J., primary, Archibald, A. T., additional, Bowman, K. W., additional, Lamarque, J.-F., additional, Naik, V., additional, Stevenson, D. S., additional, Tilmes, S., additional, Voulgarakis, A., additional, Wild, O., additional, Bergmann, D., additional, Cameron-Smith, P., additional, Cionni, I., additional, Collins, W. J., additional, Dalsøren, S. B., additional, Doherty, R. M., additional, Eyring, V., additional, Faluvegi, G., additional, Horowitz, L. W., additional, Josse, B., additional, Lee, Y. H., additional, MacKenzie, I. A., additional, Nagashima, T., additional, Plummer, D. A., additional, Righi, M., additional, Rumbold, S. T., additional, Skeie, R. B., additional, Shindell, D. T., additional, Strode, S. A., additional, Sudo, K., additional, Szopa, S., additional, and Zeng, G., additional

Published
2012
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31. Pre-industrial to end 21st century projections of tropospheric ozone from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

Author

Young, P. J., primary, Archibald, A. T., additional, Bowman, K. W., additional, Lamarque, J.-F., additional, Naik, V., additional, Stevenson, D. S., additional, Tilmes, S., additional, Voulgarakis, A., additional, Wild, O., additional, Bergmann, D., additional, Cameron-Smith, P., additional, Cionni, I., additional, Collins, W. J., additional, Dalsøren, S. B., additional, Doherty, R. M., additional, Eyring, V., additional, Faluvegi, G., additional, Horowitz, L. W., additional, Josse, B., additional, Lee, Y. H., additional, MacKenzie, I. A., additional, Nagashima, T., additional, Plummer, D. A., additional, Righi, M., additional, Rumbold, S. T., additional, Skeie, R. B., additional, Shindell, D. T., additional, Strode, S. A., additional, Sudo, K., additional, Szopa, S., additional, and Zeng, G., additional

Published
2012
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34. Tropospheric ozone changes, radiative forcing and attribution to emissions in the Atmospheric Chemistry and Climate Model Inter-comparison Project (ACCMIP).

Author

Stevenson, D. S., Young, P. J., Naik, V., Lamarque, J.-F., Shindell, D. T., Voulgarakis, A., Skeie, R. B., Dalsoren, S. B., Myhre, G., Berntsen, T. K., Folberth, G. A., Rumbold, S. T., Collins, W. J., MacKenzie, I. A., Doherty, R. M., Zeng, G., van Noije, T. P. C., Strunk, A., Bergmann, D., and Cameron-Smith, P.

Abstract

Ozone (O3) from 17 atmospheric chemistry models taking part in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) has been used to calculate tropospheric ozone radiative forcings (RFs). We calculate a value for the pre-industrial (1750) to present-day (2010) tropospheric ozone RF of 0.40Wm-2. The model range of pre-industrial to present-day changes in O3 produces a spread (±1 standard deviation) in RFs of ±17%. Three different radiation schemes were used -- we find differences in RFs between schemes (for the same ozone fields) of ±10%. Applying two different tropopause definitions gives differences in RFs of ±3%. Given additional (unquantified) uncertainties associated with emissions, climate-chemistry interactions and land-use change, we estimate an overall uncertainty of ±30% for the tropospheric ozone RF. Experiments carried out by a subset of six models attribute tropospheric ozone RF to increased emissions of methane (47%), nitrogen oxides (29%), carbon monoxide (15%) and non-methane volatile organic compounds (9%); earlier studies attributed more of the tropospheric ozone RF to methane and less to nitrogen oxides. Normalising RFs to changes in tropospheric column ozone, we find a global mean normalised RF of 0.042Wm-2 DU-1 , a value similar to previous work. Using normalised RFs and future tropospheric column ozone projections we calculate future tropospheric ozone RFs (Wm-2 ; relative to 1850 -- add 0.04Wm-2 to make relative to 1750) for the Representative Concentration Pathways in 2030 (2100) of: RCP2.6: 0.31 (0.16); RCP4.5: 0.38 (0.26); RCP6.0: 0.33 (0.24); and RCP8.5: 0.42 (0.56). Models show some coherent responses of ozone to climate change: decreases in the tropical lower troposphere, associated with increases in water vapour; and increases in the sub-tropical to mid-latitude upper troposphere, associated with increases in lightning and stratosphere-to-troposphere transport. [ABSTRACT FROM AUTHOR]

Published
2012
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35. Evaluation of preindustrial to present-day black carbon and its albedo forcing from ACCMIP (Atmospheric Chemistry and Climate Model Intercomparison Project).

Author

Lee, Y. H., Lamarque, J.-F., Flanner, M. G., Jiao, C., Shindell, D. T., Berntsen, T., Bisiaux, M. M., Cao, J., Collins, W. J., Curran, M., Edwards, R., Faluvegi, G., Ghan, S., Horowitz, L. W., McConnell, J. R., Myhre, G., Nagashima, T., Naik, V., Rumbold, S. T., and Skeie, R. B.

Abstract

As part of the Atmospheric Chemistry and Climate Model Intercomparison Project (AC-CMIP), we evaluate the historical black carbon (BC) aerosols simulated by 8 ACCMIP models against observations including 12 ice core records, long-term surface mass concentrations and recent Arctic BC snowpack measurements. We also estimate BC albedo forcing by performing additional simulations using offline models with prescribed meteorology from 1996-2000. We evaluated the vertical profile of BC snow concentrations from these offline simulations using the recent BC snowpack measurements. Despite using the same BC emissions, the global BC burden differs by approximately a factor of 3 among models due to differences in aerosol removal parameterizations and simulated meteorology: 34 Gg to 103 Gg in 1850 and 82 Gg to 315 Gg in 2000. However, the global BC burden from preindustrial to present-day increases by 2.5-3 times with little variation among models, roughly matching the 2.5-fold increase in total BC emissions during the same period. We find a large divergence among models at both Northern Hemisphere (NH) and Southern Hemisphere (SH) high latitude regions for BC burden and at SH high latitude regions for deposition fluxes. The ACCMIP simulations match the observed BC surface mass concentrations well in Europe and North America except at Jungfraujoch and Ispra. However, the models fail to predict the Arctic BC seasonality due to severe underestimations during winter and spring. The simulated vertically resolved BC snow concentrations are, on average, within a factor of 2-3 of the BC snowpack measurements except for Greenland and the Arctic Ocean. For the ice core evaluation, models tend to capture both the observed temporal trends and the magnitudes well at Greenland sites. However, models fail to predict the decreasing trend of BC depositions/ice-core concentrations from the 1950s to the 1970s in most Tibetan Plateau ice cores. The distinct temporal trend at the Tibetan Plateau ice cores indicates a strong influence from Western Europe, but the modeled BC increases in that period are consistent with the emission changes in Eastern Europe, the Middle East, South and East Asia. At the Alps site, the simulated BC suggests a strong influence from Europe, which agrees with the Alps ice core observations. Models successfully simulate higher BC concentrations observed at Zuoqiupu during the non-monsoon season than monsoon season, but models underpredict BC in both seasons. Despite a large divergence in BC deposition at two Antarctic ice core sites, models are able to capture the relative increase from preindustrial to present-day seen in the ice cores. In 2000 relative to 1850, globally annually averaged BC surface albedo forcing from the offline simulations ranges from 0.014 to 0.019 W m-2 among the ACCMIP models. Comparing offline and online BC albedo forcings computed by some of the same models, we find that the global annual mean can vary by up to a factor of two because of different aerosol models or different BC-snow parameterizations and snow cover. The spatial distributions of the offline BC albedo forcing in 2000 show especially high BC forcing (i.e. over 0.1 W m-2) over Manchuria, Karakoram, and most of the Former USSR. Models predict the highest global annual mean BC forcing in 1980 rather than 2000, mostly driven by the high fossil fuel and biofuel emissions in the Former USSR in 1980. [ABSTRACT FROM AUTHOR]

Published
2012
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36. Radiative forcing from modelled and observed stratospheric ozone changes due to the 11-year solar cycle.

Author

Isaksen, I. S. A., Rognerud, B., Myhre, G., Haigh, J. D., Rumbold, S. T., Shine, K. P., Zerefos, C., Tourpali, K., and Randel, W.

Abstract

Three analyses of satellite observations and two sets of model studies are used to estimate changes in the stratospheric ozone distribution from solar minimum to solar maximum and are presented for three different latitudinal bands: Poleward of 30° north, between 30° north and 30° south and poleward of 30° south. In the model studies the solar cycle impact is limited to changes in UV fluxes. There is a general agreement between satellite observation and model studies, particular at middle and high northern latitudes. Ozone increases at solar maximum with peak values around 40 km. The profiles are used to calculate the radiative forcing (RF) from solar minimum to solar maximum. The ozone RF, calculated with two different radiative transfer schemes is found to be negligible (a magnitude of 0.01Wm-2 or less), compared to the direct RF due to changes in solar irradiance, since contributions from the longwave and shortwave nearly cancel each other. The largest uncertainties in the estimates come from the lower stratosphere, where there is significant disagreement between the different ozone profiles. [ABSTRACT FROM AUTHOR]

Published
2008
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