Presented by E. Rozanov Poly-project meeting, Zurich, 26 October 2004 Poly-project “Variability of the Sun and Global Climate” Formal results of the first phase

Poly-project is grouped into 4 sub-projects: Understanding the physical reasons for the variations of the solar luminosity. Quantifying the present changes of the solar irradiation in integrated light and quantifying its spectral variations, in particular those in the UV, and reconstructing the variations of the solar irradiation for different time scales. Calculating the photo-chemical response of the atmosphere to the variable irradiation, in particular the response to the highly variable UV irradiation. Simulate the response of the global climate to the observed, reconstructed, and predicted long term solar variations, i.e. the climate response to points #2 and #3.

… with a knowledge of the flux tube structure … we could possibly make a translation of a magnetogram into a value for the irradiance, and thus use the 30 year record of magnetograms to model the irradiance. We want to explore to what extent such an undertaking is feasible. The student will focus on the physics and modeling of small-scale magnetic flux tubes, with the aim of relating the effective temperature to flux tube diameter and center-to-limb distance. His Thesis will also include the problem of deriving flux tube distribution functions as functions of heliographic latitude and phase of the solar cycle, primarily through analysis of the patterns and topologies of the magnetic fluxes recorded in solar magnetograms. Understanding the physical reasons for the variations of the solar luminosity.

What we have done: demonstrated that 5-component model atmospheres can reproduce the observed data sets, however, it is impossible to model the near-limb behavior of the contrast together with the strong increase of the flux in the UV [Wenzler et al., 2002]. verified that the reconstruction of TSI from magnetograms is possible for the past years. demonstrate that KPVT/SPM data can be employed to reconstruct total solar irradiance variations with almost the same accuracy as recently shown for MDI data [Wenzler et al., 2004]. prepared data set containing magnetic features of the Sun for reconstruction of the solar spectral irradiance for What should be done during the second phase: advance the physical understanding of the solar irradiance variations on the basis of magnetic tube model. Understanding the physical reasons for the variations of the solar luminosity.

The solar irradiance variation has to be specified in its temporal and spectral characteristics in a way that can be used by the CCM simulations. We characterize the solar luminosity variation with the state-of- the-art physical interpretation of the solar variability. We will use a three component model composed of the constant contribution of the quiet sun and the varying components by sunspots and faculae. This will allow to model the observed irradiance variation of the past 20 years …. We will be able to describe the variations with a detailed spectral energy distribution as it is required by the photochemical routines. Quantifying the present changes of the solar irradiation… (1)

What we have done: compiled observed UV fluxes for the verification of model calculations as well as an input for SOCOL [Haberreiter et al., 2002a]; developed and validated the state-of-the-art solar radiation code COSI, which we applied to compute the synthetic spectral distribution in the UV including non-LTE effects to model the UV variability using the space and ground-based magnetograms [Haberreiter et al. 2003, Haberreiter and Schmutz, 2003, 2004]; calculated solar spectral irradiance for using KPVT/SPM data. What should be done during the second phase: None, Sub-project is completed Quantifying the present changes of the solar irradiation… (1)

Based on the sun spot number and 10 Be records we will reconstruct the variation of the solar irradiance back to the little ice-age in the 17th century. Our new approach will differ from the previous ones in that we will use a model-description for the physical origin of the variations. This model will incorporate the new knowledge gained in the research project of the institute of astronomy, e.g. the flux tube distribution functions. We expect that our new approach will be more reliable and we also expect that the new reconstruction will differ considerably from present reconstructions. Quantifying the present changes of the solar irradiation… (2)

What we have done: What should be done during the second phase: Entire sub-project Quantifying the present changes of the solar irradiation… (2)

Potentially, the sun has experienced much larger variations in its energy output than we have witnessed. From literature studies of observations of so called solar analog stars we intend to characterize the magnitude of possible variations and how frequent such large variations occur. In addition, we know from the theory of stellar evolution that the luminosity of a solar type star increases by 20% within the time of the age of our sun. This temporal evolution is accompanied by a decrease in activity. We will quantify the evolution in total irradiance and the fraction of the UV radiation over the past 10 9 years. Quantifying the present changes of the solar irradiation… (3)

What we have done: What should be done during the second phase: Entire sub-project Quantifying the present changes of the solar irradiation… (3)

For the coupling of a troposphere-stratosphere-mesosphere CGM with photochemical routines we will use the 3D Atmospheric Chemical-Transport Model. This model will be validated against a variety of airborne and satellite data using meteorological input prior to be coupled with GCM. The modified version of the 3-D ACT model will then be coupled with a Troposphere-Stratosphere-Mesosphere GCM to form a GCM with interactive photochemistry or GCM/PC. This fully interactive model will be used to simulate the effects of solar variability on the temperature, chemistry and circulation of the atmosphere. Calculating the response of the atmosphere to the variable irradiation, in particular to the UV irradiation

… at least five 15-year-long steady-state model sensitivity simulations will be performed using maximum and minimum values of the spectral solar irradiance, and maximum and minimum values for the ionization events, to determine their effects on the entire atmosphere and Earth's climate. The results of the last 10 years of numerical simulations will be analyzed to establish the relation between solar input and the state of the atmosphere and to determine the statistical significance of such correlations. The geographical and seasonal pattern of the simulated changes in the atmosphere due to solar variability will also be evaluated. Simulate the response of the global climate to the observed, reconstructed, and predicted long term solar variations (1)

What we have done: developed and validated a new global CCM SOCOL [Egorova et al., 2003, 2004b]; simulated and compared with observations the atmospheric response to the variability of the solar UV flux during 11-year solar activity cycle and 27-day solar rotation cycle [Egorova et al., 2004a, Egorova et al, 2004c, Rozanov et all., 2004a, Rozanov et all., 2004b]; showed that UV-driven mechanisms play an important role in solar-climate connections [Egorova et al., 2004c]; showed that EEP-driven mechanisms can amplify UV-signal in the ozone and temperature [Rozanov et al., 2004c]; What should be done during the second phase: Sub-project is completed Calculating the response of the atmosphere to the variable irradiation, in particular to the UV irradiation

We intend to carry out at least three transient ensemble experiments for the period ( ), aimed at assessing the climate system response to the observed variations of the sun- related input. The first “control” experiment will be run without any external forcing that is with fixed spectral solar constant, ionization events frequency and greenhouse gas concentration. The second and third runs of the transient ensemble experiments will include the observed variations of greenhouse gas concentration in the troposphere (including ODS) and volcanic aerosol changes. Finally, for the third run we will add the observed or reconstructed variations of the spectral solar irradiation and ionization events. The comparison of these runs will allow elucidating the influence of solar variability on the atmospheric gas composition and weather/climate system. Simulate the response of the global climate to the observed, reconstructed, and predicted long term solar variations (2)

What we have done: developed global CCM SOCOL in transient mode [Schraner al., 2004]; prepared time evolution of SST/SI, GHG, ODS, QBO winds, stratospheric sulfate aerosol, solar radiation. Preliminary runs with SST/SI, GHG, ODS are completed [Schraner al., 2004], runs with stratospheric sulfate aerosol and solar irradiation are in progress What should be done during the second phase: Sub-project will be completed next year Simulate the response of the global climate to the observed, reconstructed, and predicted long term solar variations (2)

Publications: published, peer-reviewed (8) 1.Rozanov, E. V., M. E. Schlesinger, N. G. Andronova, F. Yang, S. L. Malyshev, V. A. Zubov, T. A. Egorova, and B. Li, Climate/chemistry effects of the Pinatubo volcanic eruption simulated by the UIUC stratosphere/troposphere GCM with interactive photochemistry, J. Geophys. Res., 107 (D21), 4594, doi: / 2001JD000974, Austin, J., D. Shindell, S. R. Beagley, C. Brühl, M. Dameris, E. Manzini, T. Nagashima, P. Newman, S. Pawson, G. Pitari, E. Rozanov, C. Schnadt, and T. G. Shepherd, Uncertainties and assessments of chemistry-climate models of the Stratosphere, Atmos. Chem. Phys., 3, 1–27, Egorova, T., E. Rozanov, V. Zubov, and I. Karol, Model for evaluations of the ozone trends (MEZON), Physics of the Atmosphere and Ocean, 39, N3, , Matthes, K., K. Kodera, J. D. Haigh, D. T. Shindell, K. Shibata, U. Langematz, E. Rozanov, and Y. Kuroda, GRIPS solar experiments inter-comparison project: initial results, Papers in Meteorology and Geophysics, 54, , Rozanov, E.V., M. E. Schlesinger, T. A. Egorova, B. Li, N. Andronova, and V.A. Zubov, Atmospheric Response to the Observed Increase of Solar UV Radiation from Solar Minimum to Solar Maximum Simulated by the UIUC Climate-Chemistry Model, J. Geoph. Res., J. Geoph. Res., 109, D01110, doi: /2003JD003796, Egorova, T., E. Rozanov, E. Manzini, M. Haberreiter, W. Schmutz, V. Zubov, and T. Peter, Chemical and dynamical response to the 11-year variability of the solar irradiance simulated with a chemistry-climate model, Geophys. Res. Lett., 31, L06119, doi: /2003GL019294, Makarova, L., A. Shirochkov, A. Nagurny, W. Schmutz and E. Rozanov, Estimated Impact of Electric Current Related to Solar Wind Energy on the Thermal Conditions of the Middle Stratosphere (20- 30km), Transactions of the Russian Academy of Sciences /Earth Science Section, Vol.394, N1, , Makarova, L., A. Shirochkov, A. Nagurny, E. Rozanov and W. Schmutz, Parameterization of the heating in the middle stratosphere due to solar wind-induced electric currents, J. Atmos. Solar- Terrestr. Phys., 66, , doi: /j.jastp , 2004.

Publications: in press, peer-reviewed (2) 1.Wenzler, T., S.K. Solanki, N.A. Krivova, D.M. Fluri, Comparison between KPVT/SPM and SoHO/MDI magnetograms with an application to solar irradiance reconstructions, Astronomy and Astrophysics, in press, Zubov, V., E. Rozanov, A. Shirochkov, L. Makarova, T. Egorova, A. Kiselev, Y. Ozolin, I. Karol and W. Schmutz, Modeling of the solar wind influence on the circulation and ozone concentration in the middle atmosphere, J. Atmos. Solar-Terrestr. Phys., in press 2004.

Publications: published, not peer-reviewed (9) 1.Haberreiter, M., I. Hubeny, E. Rozanov, I. Ruedi, C. Fröhlich, W. Schmutz and T. Wenzler, Towards a spherical code for the evaluation of solar UV-bands that influence the chemical composition in the stratosphere, In: “From Solar Min to Max: Half a Solar Cycle with SOHO”, ESA SP-508, , Rozanov, E., T. Egorova, C. Fröhlich, M. Haberreiter, T. Peter and W. Schmutz, Estimation of the ozone and temperature sensitivity to the variation of spectral solar flux, In: “From Solar Min to Max: Half a Solar Cycle with SOHO”, ESA SP- 508, , 2002a. 3.Wenzler T., Solanki S.K., Fluri D.M., Frutiger C., Fligge M., Ortiz A., Modeling solar irradiance variations: Separate models for the network and active region faculae, In: “From Solar Min to Max: Half a Solar Cycle with SOHO”, ESA SP-508, , Haberreiter, M., I. Hubeny, E. Rozanov, E. and W. Schmutz, Representation of Opacity Data in Solar Model Atmosphere Calculations, in: Stellar Atmosphere Modeling. Edited by I. Hubeny, D. Mihalas, and K. Werner, ASP Conference Ser., , Haberreiter, M. and Schmutz, W., Modelling the solar UV radiation, in: Proceedings of the ISCS Symposium, 'Solar Variability as an Input to the Earth's Environment', Edited by A. Wilson, ESA SP-535, Noordwijk: ESA Publications Division, , Egorova, T., E. Rozanov, T. Peter, M. Haberreiter, and W. Schmutz, Solar variability effects on dynamics and chemistry of the atmosphere and surface air temperature: evaluation of UV and visible radiation influence, Proceedings of the XX quadrennial ozone symposium, Ed. C. Zerefos, Kos, Greece, , Rozanov, E, T. Egorova, and W. Schmutz, Simulation of the ozone and temperature response in the stratosphere to the phase of Arctic Oscillation, Proceedings of the XX quadrennial ozone symposium, Ed. C. Zerefos, Kos, Greece, , Schraner, M., E. Rozanov,. M. Wild, T. Egorova, A. Ohmura, T. Peter, and W. Schmutz, Simulation of the ozone and temperature trends in the stratosphere for with the chemistry-climate model SOCOL, Proceedings of the XX quadrennial ozone symposium, Ed. C. Zerefos, Kos, Greece, , Zubov, V., A. Kiselev, Y. Ozolin, I. Karol, E. Rozanov, T. Egorova, W. Schmutz, A. Shirochkov, L. Makarova, Solar wind impact on the circulation and ozone in the middle atmosphere, Proceedings of the XX quadrennial ozone symposium, Ed. C. Zerefos, Kos, Greece, , 2004.

Publications: in preparation, peer-reviewed (8) 1.Egorova T., E. Rozanov, E. Manzini, M. Haberreiter, W. Schmutz, V. Zubov, and T. Peter, A new Chemistry-Climate Model SOCOL: description and validation, in preparation for Environmental Modeling and Software (draft is available). 2.Egorova T., E. Rozanov, V. Zubov, W. Schmutz, and T. Peter, Influence of solar 11-year variability on chemical composition of the stratosphere and mesosphere simulated with a chemistry-climate model, in preparation for Adv. Space. Res., (draft is available). 3.Egorova T., E. Rozanov, M. Haberreiter, W. Schmutz, V. Zubov, and T. Peter, The separation of the solar signals from the UV and visible solar irradiance using a chemistry-climate model, in preparation for J. Geoph. Res. 4.Haberreiter M., and Schmutz W., Validation of the radiative transfer code COSI, in preparation for Astronomy and Astrophysics. 5.Rozanov, E., T. Egorova, M. Haberreiter, W. Schmutz, V. Zubov, and T. Peter, The temperature and ozone response to the solar irradiance variability during 27-day Solar rotation cycle, in preparation for J. Atmos. Solar-Terrestr. Phys. 6.Wenzler, T., S. Solanki, and N. Krivova, 2004b, Solar irradiance variations for due to surface magnetic fields: Are cycles 22 and 23 different?, in preparation for Astronomy and Astrophysics. 7.Wenzler, T., S. Solanki, and N. Krivova, 2004c, Reconstruction of solar irradiance variations in cycles 21, 22 and 23 based on surface magnetic fields, in preparation for Astronomy and Astrophysics. 8.Rozanov, E, M. Schraner, M. Wild, T. Egorova, V. Zubov, A. Ohmura, W. Schmutz, and T. Peter, Assessment of the ozone and temperature trends for with a transient chemistry-climate model, in preparation for Adv. Space. Res.,

Participation in conferences: 1.SOHO-11, March 2002, Davos, Switzerland 2.Workshop on Modeling Stellar Atmospheres, April 2002, Tübingen, Germany 3.EGS General Assembly, April 2002, Nice, France 4.Colloquium IfA, July 2002, Zürich, Switzerland 5.COSPAR, November 2002, Houston, USA 6.DPT, November 2002, Tübingen, Germany 7.Workshop: Variabilité Solaire et Changement Climatique, November 2002, Annecy, France 8.SOLICE workshop, March 2002, Paris, France 9.International Radiation Symposium for NIS countries, June 2002, St. Petersburg, Russia 10.IGAC conference, September 2002, Iraclion, Greece 11.Seminar of IAC ETH, January, 2003, Zurich, Switzerland 12.SOLICE workshop, March 2003, Berlin, Germany 13.EGS-AGU-EUG, April 2003, Nice, France 14.Symposium “Solar variability and the Earth’s environment”, June 2003, Slovak Republic 15.General Assembly of IUGG, June 2003, Sapporo, Japan 16.CCM validation workshop, November 2003, Grainau, Germany 17.SOLICE workshop, December 2003, Prague, Czech Republic 18.EUG General Assembly, April 2004, Nice, France 19.Ozone-2004 Symposium, June 2004, Kos, Greece 20.COSPAR-2004, July, 2004, Paris, France 21.SPARC-III, August, 2004, Victoria, Canada

Synergy: