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8. Northern winter stratospheric temperature and ozone responses to ENSO inferred from an ensemble of Chemistry Climate Models

Author

Cagnazzo, Chiara, Manzini, Elisa, Calvo Fernández, Natalia, Douglass, A., Akiyoshi, H., Bekki, S., Chipperfield, M., Dameris, M., Deushi, M., Fischer, A. M., Garny, H., Gettelman, A., Giorgetta, M. A., Plummer, D., Rozanov, E., Shepherd, T. G., Shibata, K., Stenke, A., Struthers, H., Tian, W., Cagnazzo, Chiara, Manzini, Elisa, Calvo Fernández, Natalia, Douglass, A., Akiyoshi, H., Bekki, S., Chipperfield, M., Dameris, M., Deushi, M., Fischer, A. M., Garny, H., Gettelman, A., Giorgetta, M. A., Plummer, D., Rozanov, E., Shepherd, T. G., Shibata, K., Stenke, A., Struthers, H., and Tian, W.

Abstract

© Author(s) 2009. Chiara Cagnazzo is supported by the Centro Euro-Mediterraneo per i Cambiamenti Climatici. Elisa Manzini acknowledges the support of the EC SCOUT-O3 Integrated Project (505390-GOCE-CT-2004) for part of this work. Natalia Calvo was supported by the Spanish Ministry of Education and Science and the Fulbright Commission in Spain. CCSRNIES’s research has been supported by the Global Environmental Research Fund (GERF) of the Ministry of the Environment (MOE) of Japan (A-071). MRI simulations have been made partly with the MRI supercomputer and partly with the NIES supercomputer. CMAM simulations were supported by the Canadian Foundation for Climate and Atmospheric Sciences and run on the Environment Canada Supercomputer. We acknowledge the modeling groups for making their simulations available for this analysis, the Chemistry-Climate Model Validation Activity (CCMVal) for WCRP’s (World Climate Research Programme) SPARC (Stratospheric Processes and their Role in Climate) project for organizing and coordinating the model data analysis activity, and the British Atmospheric Data Center (BADC) for collecting and archiving the CCMVal model output. Chiara Cagnazzo and Elisa Manzini are grateful to Antonio Navarra for useful discussions. We are thankful to John Austin for suggestions and discussions on the manuscript., The connection between the El Nino Southern Oscillation (ENSO) and the Northern polar stratosphere has been established from observations and atmospheric modeling. Here a systematic inter-comparison of the sensitivity of the modeled stratosphere to ENSO in Chemistry Climate Models (CCMs) is reported. This work uses results from a number of the CCMs included in the 2006 ozone assessment. In the lower stratosphere, the mean of all model simulations reports a warming of the polar vortex during strong ENSO events in February-March, consistent with but smaller than the estimate from satellite observations and ERA40 reanalysis. The anomalous warming is associated with an anomalous dynamical increase of column ozone north of 70 degrees N that is accompanied by coherent column ozone decrease in the Tropics, in agreement with that deduced from the NIWA column ozone database, implying an increased residual circulation in the mean of all model simulations during ENSO. The spread in the model responses is partly due to the large internal stratospheric variability and it is shown that it crucially depends on the representation of the tropospheric ENSO teleconnection in the models., Canadian Foundation for Climate and Atmospheric Sciences, EC SCOUT-O3 Integrated Project, Spanish Ministry of Education and Science, Ministry of the Environment (MOE) of Japan, Fulbright Commission in Spain, Euro-Mediterraneo per i Cambiamenti Climatici, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

Published
2023

15. Stratospheric ozone: History and concepts and interactions with climate

Author

Bekki S. and Lefevre F.

Subjects
Physics, QC1-999
Abstract

Although in relatively low concentration of a few molecules per million of e e air molecules, atmospheric ozone (trioxygen O3) is essential to sustaining life on the surface of the Earth. Indeed, by absorbing solar radiation between 240 and 320 nm, it shields living organisms including humans from the very harmful ultraviolet radiation UV-B. About 90% of the ozone resides in the stratosphere, a region that extends from the tropopause, whose altitude ranges from 7 km at the poles to 17 km in the tropics, to the stratopause located at about 50 km altitude. Stratospheric ozone is communally referred as the « ozone layer ». Unlike the atmosphere surrounding it, the stratosphere is vertically stratified and stable because the temperature increases with height within it. This particularity originates from heating produced by the absorption of UV radiation by stratospheric ozone. The present chapter describes the main mechanisms that govern the natural balance of ozone in the stratosphere, and its disruption under the influence of human activities.

Published
2009
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21. Climate change projections using the IPSL-CM5 Earth System Model: from CMIP3 to CMIP5

Author

Dufresne, J.-L., Foujols, M.-A., Denvil, S., Caubel, A., Marti, O., Aumont, O., Balkanski, Y., Bekki, S., Bellenger, H., Benshila, R., Bony, S., Bopp, L., Braconnot, P., Brockmann, P., Cadule, P., Cheruy, F., Codron, F., Cozic, A., Cugnet, D., de Noblet, N., Duvel, J.-P., Ethé, C., Fairhead, L., Fichefet, T., Flavoni, S., Friedlingstein, P., Grandpeix, J.-Y., Guez, L., Guilyardi, E., Hauglustaine, D., Hourdin, F., Idelkadi, A., Ghattas, J., Joussaume, S., Kageyama, M., Krinner, G., Labetoulle, S., Lahellec, A., Lefebvre, M.-P., Lefevre, F., Levy, C., Li, Z. X., Lloyd, J., Lott, F., Madec, G., Mancip, M., Marchand, M., Masson, S., Meurdesoif, Y., Mignot, J., Musat, I., Parouty, S., Polcher, J., Rio, C., Schulz, M., Swingedouw, D., Szopa, S., Talandier, C., Terray, P., Viovy, N., and Vuichard, N.

Published
2013
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22. Multimodel Estimates of Atmospheric Lifetimes of Long-Lived Ozone-Depleting Substances: Present and Future

Author

Chipperfield, M. P, Liang, Q, Strahan, S. E, Morgenstern, O, Dhomse, S. S, Abraham, N. L, Archibald, A. T, Bekki, S, Braesicke, P, Di Genova, G, Fleming, E. L, Hardiman, S. C, Iachetti, D, Jackman, C. H, Kinnison, D. E, Marchand, M, Pitari, G, Pyle, J. A, Rozanov, E, Stenke, A, and Tummon, F

Subjects
Meteorology And Climatology, Geophysics
Abstract

We have diagnosed the lifetimes of long-lived source gases emitted at the surface and removed in the stratosphere using six three-dimensional chemistry-climate models and a two-dimensional model. The models all used the same standard photochemical data. We investigate the effect of different definitions of lifetimes, including running the models with both mixing ratio (MBC) and flux (FBC) boundary conditions. Within the same model, the lifetimes diagnosed by different methods agree very well. Using FBCs versus MBCs leads to a different tracer burden as the implied lifetime contained in theMBC value does not necessarilymatch a model's own calculated lifetime. In general, there are much larger differences in the lifetimes calculated by different models, the main causes of which are variations in the modeled rates of ascent and horizontal mixing in the tropical midlower stratosphere. The model runs have been used to compute instantaneous and steady state lifetimes. For chlorofluorocarbons (CFCs) their atmospheric distribution was far from steady state in their growth phase through to the 1980s, and the diagnosed instantaneous lifetime is accordingly much longer. Following the cessation of emissions, the resulting decay of CFCs is much closer to steady state. For 2100 conditions the model circulation speeds generally increase, but a thicker ozone layer due to recovery and climate change reduces photolysis rates. These effects compensate so the net impact on modeled lifetimes is small. For future assessments of stratospheric ozone, use of FBCs would allow a consistent balance between rate of CFC removal and model circulation rate.

Published
2014
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23. Model simulations of the impact of the 2002 Antarctic ozone hole on the midlatitudes

Author

Marchand, M., Bekki, S., Pazmino, A., Lefevre, F., Godin-Beekmann, S., and Hauchecorne, A.

Subjects
Ozone layer -- Research, Global warming -- Research, Weather -- Environmental aspects, Atmosphere -- Research, Air pollution -- Research, Earth -- Atmosphere, Earth -- Research, Earth sciences, Science and technology
Abstract

The 2002 Antarctic winter was characterized by unusually strong wave activity. The frequency and intensity of the anomalies increased in August and early September with a series of minor stratospheric warmings and culminated in a major stratospheric warming in late September. A three-dimensional high-resolution chemical transport model is used to estimate the effect of the exceptional 2002 Antarctic winter on chemical ozone loss in the midlatitudes and in polar regions. An ozone budget analysis is performed using a range of geographical and chemical ozone tracers. To highlight the unusual behavior of the 2002 winter, the same analysis is performed for the more typical 2001 winter. The ability of the model to reproduce the evolution of polar and midlatitude ozone during these two contrasted winters is first evaluated against ozonesonde measurements at middle and high latitudes. The evolution of the model-calculated 2002 ozone loss within the deep vortex core is found to be somewhat similar to that seen in the 2001 simulation until November, which is consistent with a lower-stratospheric vortex core remaining more or less isolated even during the major warming. However, the simulations suggest that the wave activity anomalies in 2002 enhanced mixing well before the major warming within the usually weakly mixed vortex edge region and, to a lesser extent, within the surrounding extravortex region. As a result of the increased permeability of the vortex edge, the export of chemically activated vortex air is more efficient during the winter in 2002 than in 2001. This has a very noticeable impact on the model-calculated midlatitude ozone loss, with destruction rates being about 2 times higher during August and September in 2002 compared to 2001. If the meteorological conditions of 2002 were to become more prevalent in the future, Antarctic polar ozone depletion would certainly be reduced, especially in the vortex edge region. However, it is also likely that polar chemical activation would affect midlatitude ozone earlier in the winter.

Published
2005

24. Long-term Ozone Changes and Associated Climate Impacts in CMIP5 Simulations

Author

Eyring, V, Arblaster, J. M, Cionni, I, Sedlacek, J, Perlwitz, J, Young, P. J, Bekki, S, Bergmann, D, Cameron-Smith, P, Collins, W. J, Faluvegi, G, Gottschaldt, K.-D, Horowitz, L. W, Kinnison, D. E, Lamarque, J.-F, Marsh, D. R, Saint-Martin, D, Shindell, D. T, Sudo, K, Szopa, S, and Watanabe, S

Subjects
Meteorology And Climatology
Abstract

Ozone changes and associated climate impacts in the Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations are analyzed over the historical (1960-2005) and future (2006-2100) period under four Representative Concentration Pathways (RCP). In contrast to CMIP3, where half of the models prescribed constant stratospheric ozone, CMIP5 models all consider past ozone depletion and future ozone recovery. Multimodel mean climatologies and long-term changes in total and tropospheric column ozone calculated from CMIP5 models with either interactive or prescribed ozone are in reasonable agreement with observations. However, some large deviations from observations exist for individual models with interactive chemistry, and these models are excluded in the projections. Stratospheric ozone projections forced with a single halogen, but four greenhouse gas (GHG) scenarios show largest differences in the northern midlatitudes and in the Arctic in spring (approximately 20 and 40 Dobson units (DU) by 2100, respectively). By 2050, these differences are much smaller and negligible over Antarctica in austral spring. Differences in future tropospheric column ozone are mainly caused by differences in methane concentrations and stratospheric input, leading to approximately 10DU increases compared to 2000 in RCP 8.5. Large variations in stratospheric ozone particularly in CMIP5 models with interactive chemistry drive correspondingly large variations in lower stratospheric temperature trends. The results also illustrate that future Southern Hemisphere summertime circulation changes are controlled by both the ozone recovery rate and the rate of GHG increases, emphasizing the importance of simulating and taking into account ozone forcings when examining future climate projections.

Published
2013
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28. Multimodel Assessment of the Factors Driving Stratospheric Ozone Evolution over the 21st Century

Author

Oman, L. D, Plummer, D. A, Waugh, D. W, Austin, J, Scinocca, J. F, Douglass, A. R, Salawitch, R. J, Canty, T, Akiyoshi, H, Bekki, S, Braesicke, P, Butchart, N, Chipperfield, M. P, Cugnet, D, Dhomse, S, Eyring, V, Frith, S, Hardiman, S. C, Kinnison, D. E, Lamarque, J.-F, Mancini, E, Marchand, M, Michou, M, Morgenstern, O, and Nakamura, T

Subjects
Geophysics
Abstract

The evolution of stratospheric ozone from 1960 to 2100 is examined in simulations from 14 chemistry-climate models, driven by prescribed levels of halogens and greenhouse gases. There is general agreement among the models that total column ozone reached a minimum around year 2000 at all latitudes, projected to be followed by an increase over the first half of the 21st century. In the second half of the 21st century, ozone is projected to continue increasing, level off, or even decrease depending on the latitude. Separation into partial columns above and below 20 hPa reveals that these latitudinal differences are almost completely caused by differences in the model projections of ozone in the lower stratosphere. At all latitudes, upper stratospheric ozone increases throughout the 21st century and is projected to return to 1960 levels well before the end of the century, although there is a spread among models in the dates that ozone returns to specific historical values. We find decreasing halogens and declining upper atmospheric temperatures, driven by increasing greenhouse gases, contribute almost equally to increases in upper stratospheric ozone. In the tropical lower stratosphere, an increase in upwelling causes a steady decrease in ozone through the 21st century, and total column ozone does not return to 1960 levels in most of the models. In contrast, lower stratospheric and total column ozone in middle and high latitudes increases during the 21st century, returning to 1960 levels well before the end of the century in most models.

Published
2010
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29. Quantifying Uncertainty in Projections of Stratospheric Ozone Over the 21st Century

Author

Charlton-Perez, A. J, Hawkins, E, Eyring, V, Cionni, I, Bodeker, G. E, Kinnison, D. E, Akiyoshi, H, Frith, S. M, Garcia, R, Gettelman, A, Lamarque, J. F, Nakamura, T, Pawson, S, Yamashita, Y, Bekki, S, Braesicke, P, Chipperfield, M. P, Dhomse, S, Marchand, M, Mancini, E, Morgenstern, O, Pitari, G, Plummer, D, Pyle, J. A, and Rozanov, E

Subjects
Meteorology And Climatology
Abstract

Future stratospheric ozone concentrations will be determined both by changes in the concentration of ozone depleting substances (ODSs) and by changes in stratospheric and tropospheric climate, including those caused by changes in anthropogenic greenhouse gases (GHGs). Since future economic development pathways and resultant emissions of GHGs are uncertain, anthropogenic climate change could be a significant source of uncertainty for future projections of stratospheric ozone. In this pilot study, using an ensemble of opportunity of chemistry-climate model (CCM) simulations, the contribution of scenario uncertainty from different plausible emissions pathways for 10 ODSs and GHGs to future ozone projections is quantified relative to the contribution from model uncertainty and internal variability of the chemistry-climate system. For both the global, annual mean ozone concentration and for ozone in specific geographical regions, differences between CCMs are the dominant source of uncertainty for the first two-thirds of the 21 st century, up-to and after the time when ozone concentrations 15 return to 1980 values. In the last third of the 21st century, dependent upon the set of greenhouse gas scenarios used, scenario uncertainty can be the dominant contributor. This result suggests that investment in chemistry-climate modelling is likely to continue to refine projections of stratospheric ozone and estimates of the return of stratospheric ozone concentrations to pre-1980 levels.

Published
2010

30. Using Transport Diagnostics to Understand Chemistry Climate Model Ozone Simulations

Author

Strahan, S. E, Douglass, A. R, Stolarski, R. S, Akiyoshi, H, Bekki, S, Braesicke, P, Butchart, N, Chipperfield, M. P, Cugnet, D, Dhomse, S, Frith, S. M, Gettleman, A, Hardiman, S. C, Kinnison, D. E, Lamarque, J.-F, Mancini, E, Marchand, M, Michou, M, Morgenstern, O, Nakamura, T, Olivie, D, Pawson, S, Pitari, G, Plummer, D. A, and Pyle, J. A

Subjects
Environment Pollution
Abstract

We demonstrate how observations of N2O and mean age in the tropical and midlatitude lower stratosphere (LS) can be used to identify realistic transport in models. The results are applied to 15 Chemistry Climate Models (CCMs) participating in the 2010 WMO assessment. Comparison of the observed and simulated N2O/mean age relationship identifies models with fast or slow circulations and reveals details of model ascent and tropical isolation. The use of this process-oriented N2O/mean age diagnostic identifies models with compensating transport deficiencies that produce fortuitous agreement with mean age. We compare the diagnosed model transport behavior with a model's ability to produce realistic LS O3 profiles in the tropics and midlatitudes. Models with the greatest tropical transport problems show the poorest agreement with observations. Models with the most realistic LS transport agree more closely with LS observations and each other. We incorporate the results of the chemistry evaluations in the SPARC CCMVal Report (2010) to explain the range of CCM predictions for the return-to-1980 dates for global (60 S-60 N) and Antarctic column ozone. Later (earlier) Antarctic return dates are generally correlated to higher (lower) vortex Cl(sub y) levels in the LS, and vortex Cl(sub y) is generally correlated with the model's circulation although model Cl(sub y) chemistry or Cl(sub y) conservation can have a significant effect. In both regions, models that have good LS transport produce a smaller range of predictions for the return-to-1980 ozone values. This study suggests that the current range of predicted return dates is unnecessarily large due to identifiable model transport deficiencies.

Published
2010

31. Multi-Model Assessment of the Factors Driving Stratospheric Ozone Evolution Over the 21st Century

Author

Oman, L. D, Plummer, D. A, Waugh, D. W, Austin, J, Scinocca, J, Douglass, A. R, Salawitch, R. J, Canty, T, Akiyoshi, H, Bekki, S, Braesicke, P, Butchart, N, Chipperfield, M. P, Cugnet, D, Dhomse, S, Eyring, V, Frith, S, Hardiman, S. C, Kinnison, D. E, Lamarque, J. F, Mancini, E, Marchand, M, Michou, M, Morgenstern, O, and Nakamura T

Subjects
Meteorology And Climatology
Abstract

The evolution of stratospheric ozone from 1960 to 2100 is examined in simulations from fourteen chemistry-climate models. There is general agreement among the models at the broadest levels, showing column ozone decreasing at all latitudes from 1960 to around 2000, then increasing at all latitudes over the first half of the 21st century, and latitudinal variations in the rate of increase and date of return to historical values. In the second half of the century, ozone is projected to continue increasing, level off or even decrease depending on the latitude, resulting in variable dates of return to historical values at latitudes where column ozone has declined below those levels. Separation into partial column above and below 20 hPa reveals that these latitudinal differences are almost completely due to differences in the lower stratosphere. At all latitudes, upper stratospheric ozone increases throughout the 21st century and returns to 1960 levels before the end of the century, although there is a spread among the models in dates that ozone returns to historical values. Using multiple linear regression, we find decreasing halogens and increasing greenhouse gases contribute almost equally to increases in the upper stratospheric ozone. In the tropical lower stratosphere an increase in tropical upwelling causes a steady decrease in ozone through the 21st century, and total column ozone does not return to 1960 levels in all models. In contrast, lower stratospheric and total column ozone in middle and high latitudes increases during the 21st century and returns to 1960 levels.

Published
2010

33. Hz. Ali in the light of futuwwatnamas and genealogies [Bazi fÜtÜvvetnameler ve Şecerenameler iŞiĞinda Hz. Alİ]

Author

Bekki S., Yalçin E., and Kırşehir Ahi Evran Üniversitesi, Fen-Edebiyat Fakültesi, Türk Dili ve Edebiyatı Bölümü

Subjects
Futuwwatnama, Alevism, Ahi evran, Hz. ali, Akhiqah, Genealogy
Abstract

Hz. Ali, who was born in Mecca 22 years before the Hegira, was the son of Abu Talib, the uncle of the Messenger Muhammed. Ali grew up under the guardianship of Hz. Muhammed for 18 years and grew up under his discipline. The last of the four great caliphs, Hz. Ali is also one of the ten people heralded with Jannah when he was alive. Hz. Ali gained great fame in courage and heroism by participating in all wars during the birth and spread of Islam. Ali married Muhammed’s daughter and his lineage survived to the present day in two branches. Hz. Ali is in the forefront of many sects in the Turkish Sufi tradition and he is considered the piri of that sect. By taking Ali as the model of the human being, he is based on an ontological basis. In Akhi tradition, Hz. Ali also has an important place. The main written sources of Akhi are futuwwatnamas and genealogies. These sources describe Hz. Ali as the master of Ahi Evran, the son of his uncle, and his father-in-law. These sources also point to Hz. Ali as the person who has a very important place in the Akhism and who is been tied up by Hz. Muhammed himself for wearing the shah of Sufis and the futuristic piety. The aim of this study is to investigate the position and the importance of Hz. Ali in Akhi (a Turkish institution) tradition. First, information about his historical personality was briefly explained. After, the perception of Hz. Ali in some sects was emphasized. Seven futuwwat descriptions and six genealogies published from the main sources of Akhism were examined. It was concluded that Hz. Ali had an important position in Akhi tradition. © 2019 Gazi Universitesi, Turk Kulturu ve Haci Bektas Veli. All rights reserved.

Published
2019

34. Clear-sky ultraviolet radiation modelling using output from the Chemistry Climate Model Initiative

Author

Lamy, K., Portafaix, T., Josse, B., Brogniez, C., Godin-Beekmann, S., Bencherif, H., Revell, L., Akiyoshi, H., Bekki, S., Hegglin, M. I., Jöckel, Patrick, Kirner, O., Liley, B., Marecal, V., Morgenstern, O., Stenke, A., Zeng, G., Abraham, N. L., Archibald, A. T., Butchart, N., Chipperfield, M. P., Di Genova, G., Deushi, M., Dhomse, S. S., Hu, R.-M., Kinnison, D., Kotkamp, M., McKenzie, R., Michou, M., O'Connor, F. M., Oman, L. D., Pitari, G., Plummer, D. A., Pyle, J. A., Rozanov, E., Saint-Martin, D., Sudo, K., Tanaka, T. Y., Visioni, D., Yoshida, K., Laboratoire de l'Atmosphère et des Cyclones (LACy), Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Optique Atmosphérique - UMR 8518 (LOA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Lille, STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), School of Chemistry and Physics [Durban], University of KwaZulu-Natal (UKZN), Institute for Atmospheric and Climate Science [Zürich] (IAC), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), School of Physical Chemical Sciences [Christchurch], University of Canterbury [Christchurch], Bodeker Scientific, National Institute for Environmental Studies (NIES), Department of Meteorology [Reading], University of Reading (UOR), DLR Institut für Physik der Atmosphäre (IPA), Deutsches Zentrum für Luft- und Raumfahrt [Oberpfaffenhofen-Wessling] (DLR), Steinbuch Centre for Computing [Karlsruhe] (SCC), Karlsruher Institut für Technologie (KIT), National Institute of Water and Atmospheric Research [Wellington] (NIWA), National Centre for Atmospheric Science [Leeds] (NCAS), Natural Environment Research Council (NERC), Department of Chemistry [Cambridge, UK], University of Cambridge [UK] (CAM), Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office [Exeter], School of Earth and Environment [Leeds] (SEE), University of Leeds, Department of Physical and Chemical Sciences [L'Aquila] (DSFC), Università degli Studi dell'Aquila (UNIVAQ), Meteorological Research Institute [Tsukuba] (MRI), Japan Meteorological Agency (JMA), National Center for Atmospheric Research [Boulder] (NCAR), NASA Goddard Space Flight Center (GSFC), Environment and Climate Change Canada, Centre for Atmospheric Science [Cambridge, UK], Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC), Graduate School of Environmental Studies [Nagoya], Nagoya University, Sibley School of Mechanical and Aerospace Engineering (MAE), Cornell University [New York], Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Météo France, Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Météo-France, Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University of KwaZulu-Natal [Durban, Afrique du Sud] (UKZN), Università degli Studi dell'Aquila = University of L'Aquila (UNIVAQ), and Météo France-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], EMAC, ozone, Atmospheric physics and chemistry, MESSy, CCMI, Erdsystem-Modellierung, clear-sky, ultraviolot radiation, chemistry-climate modelling
Abstract

We have derived values of the ultraviolet index (UVI) at solar noon using the Tropospheric Ultraviolet Model (TUV) driven by ozone, temperature and aerosol fields from climate simulations of the first phase of the Chemistry-Climate Model Initiative (CCMI-1). Since clouds remain one of the largest uncertainties in climate projections, we simulated only the clear-sky UVI. We compared the modelled UVI climatologies against present-day climatological values of UVI derived from both satellite data (the OMI-Aura OMUVBd product) and ground-based measurements (from the NDACC network). Depending on the region, relative differences between the UVI obtained from CCMI/TUV calculations and the ground-based measurements ranged between −5.9 % and 10.6 %. We then calculated the UVI evolution throughout the 21st century for the four Representative Concentration Pathways (RCPs 2.6, 4.5, 6.0 and 8.5). Compared to 1960s values, we found an average increase in the UVI in 2100 (of 2 %–4 %) in the tropical belt (30∘ N–30∘ S). For the mid-latitudes, we observed a 1.8 % to 3.4 % increase in the Southern Hemisphere for RCPs 2.6, 4.5 and 6.0 and found a 2.3 % decrease in RCP 8.5. Higher increases in UVI are projected in the Northern Hemisphere except for RCP 8.5. At high latitudes, ozone recovery is well identified and induces a complete return of mean UVI levels to 1960 values for RCP 8.5 in the Southern Hemisphere. In the Northern Hemisphere, UVI levels in 2100 are higher by 0.5 % to 5.5 % for RCPs 2.6, 4.5 and 6.0 and they are lower by 7.9 % for RCP 8.5. We analysed the impacts of greenhouse gases (GHGs) and ozone-depleting substances (ODSs) on UVI from 1960 by comparing CCMI sensitivity simulations (1960–2100) with fixed GHGs or ODSs at their respective 1960 levels. As expected with ODS fixed at their 1960 levels, there is no large decrease in ozone levels and consequently no sudden increase in UVI levels. With fixed GHG, we observed a delayed return of ozone to 1960 values, with a corresponding pattern of change observed on UVI, and looking at the UVI difference between 2090s values and 1960s values, we found an 8 % increase in the tropical belt during the summer of each hemisphere. Finally we show that, while in the Southern Hemisphere the UVI is mainly driven by total ozone column, in the Northern Hemisphere both total ozone column and aerosol optical depth drive UVI levels, with aerosol optical depth having twice as much influence on the UVI as total ozone column does. ISSN:1680-7375 ISSN:1680-7367

Published
2019
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35. Multi-model comparison of the volcanic sulfate deposition from the 1815 eruption of Mt. Tambora

Author

Marshall, L., Schmidt, A., Toohey, M., Carslaw, K. S., Mann, G. W., Sigl, M., Khodri, Myriam, Timmreck, C., Zanchettin, D., Ball, W. T., Bekki, S., Brooke, J. S. A., Dhomse, S., Johnson, C., Lamarque, J. F., LeGrande, A. N., Mills, M. J., Niemeier, U., Pope, J. O., Poulain, V., Robock, A., Rozanov, E., Stenke, A., Sukhodolov, T., Tilmes, S., Tsigaridis, K., Tummon, F., Institute for Climate and Atmospheric Science [Leeds] (ICAS), School of Earth and Environment [Leeds] (SEE), University of Leeds-University of Leeds, Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Max-Planck-Institut für Meteorologie (MPI-M), Max-Planck-Gesellschaft, National Centre for Atmospheric Science [Leeds] (NCAS), Natural Environment Research Council (NERC), Laboratory of Environmental Chemistry [Villigen] (LUC), Paul Scherrer Institute (PSI), Océan et variabilité du climat (VARCLIM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Max Planck Institute for Meteorology (MPI-M), Department of Environmental Sciences, Informatics and Statistics [Venezia], University of Ca’ Foscari [Venice, Italy], Institute for Atmospheric and Climate Science [Zürich] (IAC), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Physikalisch-Meteorologisches Observatorium Davos/World Radiation Center (PMOD/WRC), STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), School of Chemistry [Leeds], University of Leeds, Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office [Exeter], Atmospheric Chemistry Observations and Modeling Laboratory (ACOML), National Center for Atmospheric Research [Boulder] (NCAR), NASA Goddard Space Flight Center (GSFC), British Antarctic Survey (BAS), Processus de la variabilité climatique tropicale et impacts (PARVATI), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Environmental Sciences [New Brunswick], School of Environmental and Biological Sciences [New Brunswick], Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers)-Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers), NASA Goddard Institute for Space Studies (GISS), Center for Climate Systems Research [New York] (CCSR), Columbia University [New York], The Arctic University of Norway [Tromsø, Norway] (UiT), US National Science Foundation grant AGS-1430051, German Federal Ministry of Education and Research (BMBF), research program 'MiKliP' (FKZ: 01LP1517B, Swiss National Science Foundation grant 20F121_138017, NERC grant NEK/K012150/1, ANR-10-LABX-0018,L-IPSL,LabEx Institut Pierre Simon Laplace (IPSL): Understand climate and anticipate future changes(2010), European Project: 603557,EC:FP7:ENV,FP7-ENV-2013-two-stage,STRATOCLIM(2013), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and The Arctic University of Norway (UiT)

Subjects
[SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, Settore GEO/12 - Oceanografia e Fisica dell'Atmosfera
Abstract

Source at https://doi.org/10.5194/acp-18-2307-2018. The eruption of Mt. Tambora in 1815 was the largest volcanic eruption of the past 500 years. The eruption had significant climatic impacts, leading to the 1816 "year without a summer", and remains a valuable event from which to understand the climatic effects of large stratospheric volcanic sulfur dioxide injections. The eruption also resulted in one of the strongest and most easily identifiable volcanic sulfate signals in polar ice cores, which are widely used to reconstruct the timing and atmospheric sulfate loading of past eruptions. As part of the Model Intercomparison Project on the climatic response to Volcanic forcing (VolMIP), five state-of-the-art global aerosol models simulated this eruption. We analyse both simulated background (no Tambora) and volcanic (with Tambora) sulfate deposition to polar regions and compare to ice core records. The models simulate overall similar patterns of background sulfate deposition, although there are differences in regional details and magnitude. However, the volcanic sulfate deposition varies considerably between the models with differences in timing, spatial pattern and magnitude. Mean simulated deposited sulfate on Antarctica ranges from 19 to 264 kg km−2 and on Greenland from 31 to 194 kg km−2, as compared to the mean ice-core-derived estimates of roughly 50 kg km−2 for both Greenland and Antarctica. The ratio of the hemispheric atmospheric sulfate aerosol burden after the eruption to the average ice sheet deposited sulfate varies between models by up to a factor of 15. Sources of this inter-model variability include differences in both the formation and the transport of sulfate aerosol. Our results suggest that deriving relationships between sulfate deposited on ice sheets and atmospheric sulfate burdens from model simulations may be associated with greater uncertainties than previously thought.

Published
2018
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37. Drivers and Surface Signal of Interannual Variability of Boreal Stratospheric Final Warmings

Author

Thiéblemont, R., Ayarzagüena, B., Matthes, Katja, Bekki, S., Abalichin, J., Langematz, U., Thiéblemont, R., Ayarzagüena, B., Matthes, Katja, Bekki, S., Abalichin, J., and Langematz, U.

Abstract

Springtime stratospheric final warming (SFW) variability has been suggested to be linked to the tropospheric circulation, particularly over the North Atlantic sector. These findings, however, are based on reanalysis data that cover a rather short period of time (1979 to present). The present work aims to improve the understanding of drivers, trends and surface impact of dynamical variability of boreal SFWs using chemistry‐climate models. We use multidecadal integrations of the fully coupled chemistry‐climate models Community Earth System Model version 1 (Whole Atmosphere Community Climate Model) and ECHAM/Modular Earth Submodel System Atmospheric Chemistry‐O. Four sensitivity experiments are analyzed to assess the impact of external factors; namely, the quasi‐biennial oscillation, sea surface temperature (SST) variability, and anthropogenic emissions. SFWs are classified into two types with respect to their vertical development; that is, events which occur first in the midstratosphere (10‐hPa first SFWs) or first in the upper stratosphere (1‐hPa first SFWs). Our results confirm previous reanalysis results regarding the differences in the time evolution of stratospheric conditions and near‐surface circulation between 10 and 1‐hPa first SFWs. Additionally, a tripolar SST pattern is, for the first time, identified over the North Atlantic in spring months related to the SFW variability. Our analysis of the influence of remote modulators on SFWs revealed that the occurrence of major warmings in the previous winter favors the occurrence of 10‐hPa first SFWs later on. We further found that quasi‐biennial oscillation and SST variability significantly affect the ratio between 1‐hPa first and 10‐hPa first SFWs. Finally, our results suggest that ozone recovery may impact the timing of the occurrence of 1‐hPa first SFWs.

Published
2019
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38. Photochemical box modelling of volcanic SO2 oxidation: isotopic constraints

Author

Galeazzo, T, Bekki, S, Martin, E, Savarino, J, Arnold, SR, STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institute for Climate and Atmospheric Science [Leeds] (ICAS), School of Earth and Environment [Leeds] (SEE), University of Leeds-University of Leeds, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), and Université Grenoble Alpes (UGA)

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere
Abstract

The photochemical box model CiTTyCAT is used to analyse the absence of oxygen mass-independent anomalies (O-MIF) in volcanic sulfates produced in the troposphere. An aqueous sulfur oxidation module is implemented in the model and coupled to an oxygen isotopic scheme describing the transfer of O-MIF during the oxidation of SO2 by OH in the gas-phase, and by H2O2, O3 and O2 catalysed by TMI in the liquid phase. Multiple model simulations are performed in order to explore the relative importance of the various oxidation pathways for a range of plausible conditions in volcanic plumes. Note that the chemical conditions prevailing in dense volcanic plumes are radically different from those prevailing in the surrounding background air. The first salient finding is that, according to model calculations, OH is expected to carry a very significant O-MIF in sulfur-rich volcanic plumes and, hence, that the volcanic sulfate produced in the gas phase would have a very significant positive isotopic enrichment. The second finding is that, although H2O2 is a major oxidant of SO2 throughout the troposphere, it is very rapidly consumed in sulfur-rich volcanic plumes. As a result, H2O2 is found to be a minor oxidant for volcanic SO2. According to the simulations, oxidation of SO2 by O3 is negligible because volcanic aqueous phases are too acidic. The model predictions of minor or negligible sulfur oxidation by H2O2 and O3, two oxidants carrying large O-MIF, are consistent with the absence of O-MIF seen in most isotopic measurements of volcanic tropospheric sulfate. The third finding is that oxidation by O2∕TMI in volcanic plumes could be very substantial and, in some cases, dominant, notably because the rates of SO2 oxidation by OH, H2O2 and O3 are vastly reduced in a volcanic plume compared to the background air. Only cases where sulfur oxidation by O2∕TMI is very dominant can explain the isotopic composition of volcanic tropospheric sulfate.

Published
2018
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39. The representation of solar cycle signals in stratospheric ozone – Part 2: Analysis of global models

Author

Maycock, AC, Matthes, K, Tegtmeier, S, Schmidt, H, Thiéblemont, R, Hood, L, Akiyoshi, H, Bekki, S, Deushi, M, Jöckel, P, Kirner, O, Kunze, M, Marchand, M, Marsh, DR, Michou, M, Revell, LE, Rozanov, E, Stenke, A, Yamashita, Y, and Yoshida, K

Abstract

The impact of changes in incoming solar irradiance on stratospheric ozone abundances should be included in climate model simulations to fully capture the atmospheric response to solar variability. This study presents the first systematic comparison of the solar-ozone response (SOR) during the 11 year solar cycle amongst different chemistry-climate models (CCMs) and ozone 5 databases specified in climate models that do not include chemistry. We analyse the SOR in eight CCMs from the WCRP/SPARC Chemistry-Climate Model Initiative (CCMI-1) and compare these with three ozone databases: the Bodeker Scientific database, the SPARC/AC&C database for CMIP5, and the SPARC/CCMI database for CMIP6. The results reveal substantial differences in the representation of the SOR between the CMIP5 and CMIP6 ozone databases. The peak amplitude of the 10 SOR in the upper stratosphere (1-5 hPa) decreases from 5% to 2% between the CMIP5 and CMIP6 databases. This difference is because the CMIP5 database was constructed from a regression model fit to satellite observations, whereas the CMIP6 database is constructed from CCM simulations, 1 Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2017-477, 2017 Manuscript under review for journal Atmos. Chem. Phys. Discussion started: 31 May 2017 c Author(s) 2017. CC-BY 3.0 License. which use a spectral solar irradiance (SSI) dataset with relatively weak UV forcing. The SOR in the CMIP6 ozone database is therefore implicitly more similar to the SOR in the CCMI-1 models than 15 to the CMIP5 ozone database, which shows a greater resemblance in amplitude and structure to the SOR in the Bodeker database. The latitudinal structure of the annual mean SOR in the CMIP6 ozone database and CCMI-1 models is considerably smoother than in the CMIP5 database, which shows strong gradients in the SOR across the midlatitudes owing to the paucity of observations at high latitudes. The SORs in the CMIP6 ozone database and in the CCMI-1 models show a strong seasonal 20 dependence, including large meridional gradients at mid to high latitudes during winter; such seasonal variations in the SOR are not included in the CMIP5 ozone database. Sensitivity experiments with a global atmospheric model without chemistry (ECHAM6.3) are performed to assess the impact of changes in the representation of the SOR and SSI forcing between CMIP5 and CMIP6. The experiments show that the smaller amplitude of the SOR in the CMIP6 ozone database compared to 25 CMIP5 causes a decrease in the modelled tropical stratospheric temperature response over the solar cycle of up to 0.6 K, or around 50% of the total amplitude. The changes in the SOR explain most of the difference in the amplitude of the tropical stratospheric temperature response in the case with combined changes in SOR and SSI between CMIP5 and CMIP6. The results emphasise the importance of adequately representing the SOR in climate models to capture the impact of solar variability 30 on the atmosphere. Since a number of limitations in the representation of the SOR in the CMIP5 ozone database have been identified, CMIP6 models without chemistry are encouraged to use the CMIP6 ozone database to capture the climate impacts of solar variability.

Published
2017

41. SOLAR-ISS: A new reference spectrum based on SOLAR/SOLSPEC observations

Author

Meftah, M., primary, Damé, L., additional, Bolsée, D., additional, Hauchecorne, A., additional, Pereira, N., additional, Sluse, D., additional, Cessateur, G., additional, Irbah, A., additional, Bureau, J., additional, Weber, M., additional, Bramstedt, K., additional, Hilbig, T., additional, Thiéblemont, R., additional, Marchand, M., additional, Lefèvre, F., additional, Sarkissian, A., additional, and Bekki, S., additional

Published
2018
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42. Effect of ozone depletion on atmospheric CH4 and CO concentrations

Author

Bekki, S., Law, K.S., and Pyle, J.A.

Subjects
Ozone layer depletion -- Analysis, Carbon monoxide -- Environmental aspects, Methane -- Environmental aspects, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

A two-dimensional atmospheric model and the Total Ozone Mapping Spectrometer facilitate the study of the correlation between stratospheric ozone decrease and the changes in atmospheric CH4 and CO concentrations. Nearly half the fall in CH4 and CO growth rates in 1992 can be attributed to low values in stratospheric ozone concentration. Ozone depletion contributes to decrease in the growth rates of CH4 and CO by exposing the troposphere to more ultraviolet radiation.

Published
1994

44. Review of the global models used within the Chemistry-Climate Model Initiative (CCMI)

Author

Morgenstern, O, Hegglin, MI, Rozanov, E, O'Connor, FM, Abraham, NL, Akiyoshi, H, Archibald, AT, Bekki, S, Butchart, N, Chipperfield, MP, Deushi, M, Dhomse, SS, Garcia, RR, Hardiman, SC, Horowitz, LW, Jöckel, P, Josse, B, Kinnison, D, Lin, M, Mancini, E, Manyin, ME, Marchand, M, Marécal, V, Michou, M, Oman, LD, Pitari, G, Plummer, DA, Revell, LE, Saint-Martin, D, Schofield, R, Stenke, A, Stone, K, Sudo, K, Tanaka, TY, Tilmes, S, Yamashita, Y, Yoshida, K, and Zeng, G

Abstract

We present an overview of state-of-the-artchemistry–climate and chemistry transport models that areused within phase 1 of the Chemistry–Climate Model Initia-tive (CCMI-1). The CCMI aims to conduct a detailed evalua-tion of participating models using process-oriented diagnos-tics derived from observations in order to gain confidence inthe models’ projections of the stratospheric ozone layer, tro-pospheric composition, air quality, where applicable globalclimate change, and the interactions between them. Interpre-tation of these diagnostics requires detailed knowledge of theradiative, chemical, dynamical, and physical processes incor-porated in the models. Also an understanding of the degree towhich CCMI-1 recommendations for simulations have beenfollowed is necessary to understand model responses to an-thropogenic and natural forcing and also to explain inter-model differences. This becomes even more important giventhe ongoing development and the ever-growing complexityof these models. This paper also provides an overview ofthe available CCMI-1 simulations with the aim of informingCCMI data users., Geoscientific Model Development, 10 (2), ISSN:1991-9603, ISSN:1991-959X

Published
2017

45. Role of sulphur photochemistry in tropical ozone changes after the eruption of Mount Pinatubo

Author

Bekki, S., Toumi, R., and Pyle, J.A.

Subjects
Mount Pinatubo -- Environmental aspects, Ozone layer depletion -- Models, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

The eruption of Mount Pinatubo resulted in perturbations in the tropical ozone layer characterized by ozone reductions up to 24-25 kilometers and increases above 28 kilometers. The eruption also resulted in injection of alarge amount of sulfur dioxide in the stratosphere. Sulfur dioxide may form ozone as well as reduce ozone production depending on the radiation absorbed. The role of sulfur dioxide in the disturbances in the ozone layer after the Mount Pinatubo eruption was investigated by simulation modeling. The model was in good agreement with most of the ozone measurements following the eruption.

Published
1993

46. Evaluation of simulated photolysis rates and their response to solar irradiance variability

Author

Sukhodolov, T, Rozanov, E, Ball, WT, Bais, A, Tourpali, K, Shapiro, AI, Telford, P, Smyshlyaev, S, Fomin, B, Sander, R, Bossay, S, Bekki, S, Marchand, M, Chipperfield, MP, Dhomse, S, Haigh, JD, Peter, T, and Schmutz, W

Subjects
CHEMICAL-MODELS, Science & Technology, STRATOSPHERIC OZONE, SPECTRAL IRRADIANCE, Physical Sciences, ROTATION CYCLE, ACCURATE SIMULATION, HEATING RATES, Meteorology & Atmospheric Sciences, CHEMISTRY-CLIMATE MODEL, DYNAMICAL RESPONSE, CIRCULATION MODEL, MIDDLE ATMOSPHERE
Abstract

The state of the stratospheric ozone layer and the temperature structure of the atmosphere are largely controlled by the solar spectral irradiance (SSI) through its influence on heating and photolysis rates. This study focuses on the uncertainties in the photolysis rate response to solar irradiance variability related to the choice of SSI data set and to the performance of the photolysis codes used in global chemistry-climate models. To estimate the impact of SSI uncertainties, we compared several photolysis rates calculated with the radiative transfer model libRadtran, using SSI calculated with two models and observed during the Solar Radiation and Climate Experiment (SORCE) satellite mission. The importance of the calculated differences in the photolysis rate response for ozone and temperature changes has been estimated using 1-D a radiative-convective-photochemical model. We demonstrate that the main photolysis reactions, responsible for the solar signal in the stratosphere, are highly sensitive to the spectral distribution of SSI variations. Accordingly, the ozone changes and related ozone-temperature feedback are shown to depend substantially on the SSI data set being used, which highlights the necessity of obtaining accurate SSI variations. To evaluate the performance of photolysis codes, we compared the results of eight, widely used, photolysis codes against two reference schemes. We show that, in most cases, absolute values of the photolysis rates and their response to applied SSI changes agree within 30%. However, larger errors may appear in specific atmospheric regions because of differences, for instance, in the treatment of Rayleigh scattering, quantum yields, or absorption cross sections.

Published
2016

49. Review of the global models used within phase 1 of the Chemistry-Climate Model Initiative (CCMI)

Author

Morgenstern, O, Hegglin, MI, Rozanov, E, O'Connor, FM, Abraham, NL, Akiyoshi, H, Archibald, AT, Bekki, S, Butchart, N, Chipperfield, MP, Deushi, M, Dhomse, SS, Garcia, RR, Hardiman, SC, Horowitz, LW, Joeckel, P, Josse, B, Kinnison, D, Lin, M, Mancini, E, Manyin, ME, Marchand, M, Marecal, V, Michou, M, Oman, LD, Pitari, G, Plummer, DA, Revell, LE, Saint-Martin, D, Schofield, R, Stenke, A, Stone, K, Sudo, K, Tanaka, TY, Tilmes, S, Yamashita, Y, Yoshida, K, Zeng, G, Morgenstern, O, Hegglin, MI, Rozanov, E, O'Connor, FM, Abraham, NL, Akiyoshi, H, Archibald, AT, Bekki, S, Butchart, N, Chipperfield, MP, Deushi, M, Dhomse, SS, Garcia, RR, Hardiman, SC, Horowitz, LW, Joeckel, P, Josse, B, Kinnison, D, Lin, M, Mancini, E, Manyin, ME, Marchand, M, Marecal, V, Michou, M, Oman, LD, Pitari, G, Plummer, DA, Revell, LE, Saint-Martin, D, Schofield, R, Stenke, A, Stone, K, Sudo, K, Tanaka, TY, Tilmes, S, Yamashita, Y, Yoshida, K, and Zeng, G

Abstract

We present an overview of state-of-the-art chemistry–climate and chemistry transport models that are used within phase 1 of the Chemistry–Climate Model Initiative (CCMI-1). The CCMI aims to conduct a detailed evaluation of participating models using process-oriented diagnostics derived from observations in order to gain confidence in the models' projections of the stratospheric ozone layer, tropospheric composition, air quality, where applicable global climate change, and the interactions between them. Interpretation of these diagnostics requires detailed knowledge of the radiative, chemical, dynamical, and physical processes incorporated in the models. Also an understanding of the degree to which CCMI-1 recommendations for simulations have been followed is necessary to understand model responses to anthropogenic and natural forcing and also to explain inter-model differences. This becomes even more important given the ongoing development and the ever-growing complexity of these models. This paper also provides an overview of the available CCMI-1 simulations with the aim of informing CCMI data users.

Published
2017

50. The organic connection between introduction of the book of dedem korkut and the stories [Dedem korkut kitabi’nin mukaddimesi ile boylar arasindaki organik bağ]

Author

Bekki S. and Kırşehir Ahi Evran Üniversitesi, Fen-Edebiyat Fakültesi, Türk Dili ve Edebiyatı Bölümü

Subjects
Transcribers, Korkut ata, The female types, The book of dedem korkut, Introduction (mukaddime)
Abstract

The Book of Dedem Korkut which is one of the most important cultural heritages for Turkish and world literatures arrives today with two copies, one of which is shorter. The Dresden copy has an introduction and twelve stories. The shorter Vatican copy has an introduction and six stories. The introduction is on the pages between 3a (1) - 6b (12) in the Dresden copy and 58b (2) - 60a (13) in the Vatican copy. In the beginning of the introduction, there is a prayer and Korkut Ata / Dede Korkut is introduced. Then, his aphorisms in the presence of the Oğuz lords take place. These aphorisms divide into 4 groups, the sentences in the first group end with the addition ‘-mez’, the second group’s addition is ‘yig’, third group’s addition is ‘bilür’ and the fourth group’s addition is ‘görklü’ and there is always a prayer at the end of every group. The intro ends up with the assessments about the female types. Especially Muallim Rifat from Kilis city (Kilisli Muallim Rifat) and the other researchers think that, the intro has been added into the book later. But, noone knows who has added the intro in the book. In the researches about the book, there is no assessment on a direct connection between intro and the themes in the stories, except the little ascriptions. In this study, the elements in the introduction are shown as the reflections of the stories; the organic connection between intro and the stories is powerful, however the female types in the intro are different from the female types in the stories. © 2015, Milli Folklor Dergisi. All rights reserved.

Published
2015

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