Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 9 9 2009 10.5194/acp-9-3001-2009 http://www.atmos-chem-phys.net/9/3001/2009/ http://www.atmos-chem-phys.net/9/3001/2009/acp-9-3001-2009.html http://www.atmos-chem-phys.net/9/3001/2009/acp-9-3001-2009.pdf 3001 3009 2009-05-11 Simulation of the climate impact of Mt. Pinatubo eruption using ECHAM5 – Part 2: Sensitivity to the phase of the QBO and ENSO M. A. Thomas manu.thomas@zmaw.de M. A. Giorgetta C. Timmreck H.-F. Graf G. Stenchikov Max-Planck Institute for Meteorology, Hamburg, Germany Center for Atmospheric Sciences, Cambridge University, Cambridge, UK Department of Environmental Sciences, Rutgers – The State University of NJ, New Jersey, USA The sensitivity of the climate impact of Mt. Pinatubo eruption in the tropics and extratropics to different QBO phases is investigated. Mt. Pinatubo erupted in June 1991 during the easterly phase of the QBO at 30 hPa and the phase change to westerly took place in August 1992. Here, the consequences are analyzed if the QBO phase had been in the opposite phase during the eruption of Mt. Pinatubo. Hence, in this study, simulations are carried out using the middle atmosphere configuration of ECHAM5 general circulation model for two cases – one with the observed QBO phase and the other with the opposite QBO phase. The response of temperature and geopotential height in the lower stratosphere is evaluated for the following cases – (1) when only the effects of the QBO are included and (2) when the effects of aerosols, QBO and SSTs (combined response) are included. The tropical QBO signature in the lower stratospheric temperature is well captured in the pure QBO responses and in the combined (aerosol + ocean + QBO) responses. The response of the extratropical atmosphere to the QBO during the second winter after the eruption is captured realistically in the case of the combined forcing showing a strengthening of the polar vortex when the QBO is in its westerly phase and a warm, weak polar vortex in the easterly QBO phase. The vortex is disturbed during the first winter irrespective of the QBO phases in the combined responses and this may be due to the strong influences of El Niño during the first winters after eruption. However, the pure QBO experiments do not realistically reproduce a strengthening of the polar vortex in the westerly QBO phase, even though below normal temperatures in the high latitudes are seen in October-November-December months when the opposite QBO phase is prescribed instead of the December-January-February winter months used here for averaging. Andrews, D. J., Holton, J. R., and Leovy, C. B.: Middle atmosphere dynamics, Academic Press, 489 pp., 1987. Baldwin, M. P. and Dunkerton, T. J.: Biennial, quasi-biennial and decadal oscillations of potential vorticity in the northern stratosphere, J. Geophys. Res., 103, 3919–3928, 1998a. Baldwin, M. P., Gray, L. J., Dunkerton, T. J., Hamilton, K., Haynes, P. H., Randel, W. J., Holton, J. R., Alexander, M. J., Hiorta, I., Horinouchi, T., Jones, D. B. A., Kinnersley, J. S., Marquardt, C., Sato, K., and Takahashi, M.: The quasi-biennial oscillation, Rev. Geophys., 39(2), 170–229, 2001. Bruhwiler, L. and Hamilton, K.: A numerical simulation of the stratospheric ozone quasi biennial oscillation using a comprehensive general circulation model, J. Geophys. Res., 104, 30523–30557, 1999. Calvo, N., Giorgetta, M. A., and Pena-Ortiz, C.: Sensitivity of the boreal winter circulation in the middle atmosphere to the quasi-biennial oscillation in MAECHAM5 simulations, J. Geophys. Res., 112, D10124, 2007. Garfinkel, C. I. and Hartmann, D. L.: Effects of El Niño -Southern Oscillation and the Quasi-Biennial Oscillation on polar temperatures in the stratosphere, J. Geophys. Res., 112, D19112, doi:10.1029/2007JD008481, 2007. Giorgetta, M. and Bengtsson, L.: The potential role of the quasi-biennial oscillation in the stratosphere-troposphere exchange as found in water vapor in general circulation model experiments, J. Geophys. Res., 104, 6003–6019, 1999. Giorgetta, M., Manzini, E., and Roeckner, E.: Forcing of the quasi-biennial oscillation from a broad spectrum of atmospheric waves, Geophys. Res. Lett., 29, 86–90, 2002. Giorgetta, M., Manzini, E., Roeckner, E., Esch, M., and Bengtsson, L.: Climatology and forcing of the Quasi-Biennial Oscillation in the MAECHAM5 model, J. Climate, 19, 3882–3901, 2006. Graf, H.-F., Kirchner, I., Robock, A., and Schultz, I.: Pinatubo eruption winter climate effects: Model versus observations, Clim. Dynam., 9, 81–93, 1993. Hamilton, K.: Effects of an imposed quasi-biennial oscillation in a comprehensive troposphere-stratosphere-mesosphere general circulation model, J. Atmos. Sci., 55, 2393–2418, 1998. Holton, J. R. and Tan, H.-C.: The influence of the equatorial quasi-biennial oscillation on the global circulation at 50 mb, J. Atmos. Sci., 37, 2200–2208, 1980. Holton, J. R. and Tan, H.-C. : The quasi biennial oscillation in the Northern Hemisphere lower stratosphere, J. Meteorol. Soc. Jpn., 60, 140–148, 1982. Kirchner, I. and Graf, H.-F.: Volcanoes and El Niño: Signal separation in Northern Hemisphere winter, Clim. Dynam., 11, 341–358, 1995. Labitzke, K. and Van Loon, H.: Association between the 11-year solar cycle, the QBO, and the atmosphere, Part I, The troposphere and the stratosphere in the Northern Hemisphere in winter, J. Atmos. Terr. Phys., 50, 197–207, 1988. Labitzke, K.: Sunspots, the QBO and the stratospheric temperature in the North Polar region, Geophys. Res. Lett., 14, 535–537, 1987. Manzini, E. and McFarlane, N. A.: The effect of varying the source spectrum of a gravity wave parameterization in a middle atmosphere general circulation model, J. Geophys. Res., 103, 31523–31539, 1998. Manzini, E., Steil, B., Brühl, C., Giorgetta, M. A., and Kruger,~K.: A new interactive chemistry-climate model: Sensitivity of the middle atmosphere to ozone depletion and increase in greenhouse gases and implications for recent stratospheric cooling, J. Geophys. Res., 108, 4429, doi:10.1029/2002JD002977, 2003. Manzini, E., Giorgetta, M. A., Esch, M., Kornblueh, L., and Roeckner, E.: The influence of sea surface temperatures on the northern winter stratosphere: Ensemble simulations with the MAECHAM5 model, J. Climate, 19, 3863–3881, 2006. Niwano, M. and Takahashi, M.: The influence of the equatorial QBO on the Northern Hemisphere winter circulation of a GCM, J. Meteorol. Soc. Jpn., 76, 453–461, 1998. O'Sullivan, D. and Dunkerton, T. J.: Seasonal development of the extratropical QBO in a numerical model of the middle atmosphere, J. Atmos. Sci., 51, 3706–3721, 1994. O'Sullivan, D. and Young, R. E.: Modeling the quasi-biennial oscillation's effect on the winter stratospheric circulation, J. Atmos. Sci., 49, 2437–2448, 1992. Plumb, R. A. and Bell, R. C.: A model of the quasi-biennial oscillation on an equatorial beta-plane, Q. J. Roy. Meteor. Soc., 108, 335–352, 1982. Punge, H. J. and Giorgetta, M. A.: Net effect of the QBO in a chemistry climate model, Atmos. Chem. Phys., 8, 6505–6525, 2008. Roeckner, E., Arpe, K., Bengtsson, L., Christoph, M., Claussen, M., Dumenil, L., Esch, M., Giorgetta, M. A., Schlese, U., and Schulzweida, U.: The atmospheric general circulation model ECHAM4: Model description and simulation of present-day climate, Max Planck Institut for Meteorology, Report No., 218, Hamburg, 1996. Robock, A. and Mao, J.: The volcanic signal in surface temperature observations, J. Climate, 8, 1086–1103, 1995. Scaife, A., Buchart, N., Warner, C. D., Stainforth, D., Norton, W., and Austin, J.: Realistic quasi-biennial oscillation in a simulation of the global climate, Geophys. Res. Lett., 27, 3481–3484, 2000. Schoeberl, M. R., Douglass, A. R., Newman, P. A., Lait, L. R., Lary, D., Waters, J., Livesey, N., Froidevaux, L., Lambert, A., Read, W., Filipiak, M. J., and Pumphrey, H. C.: QBO and annual cycle variations in tropical lower stratosphere trace gases from HALOE and Aura MLS Observations, J. Geophys. Res., 113, D05301, doi:10.1029/2007JD008678, 2008. Steil, B., Dameris, M., Brühl, C., Crutzen, P. J., Grewe, V., Ponater, M., and Sausen, R.: Development of a chemistry module for GCMs: first results of a multiannual integration, Ann. Geophys., 16, 205–228, 1998. Stenchikov, G., Robock, A., Ramaswamy, V., Schwarzkopf, M. D., Hamilton, K., and Ramachandran, S.: Arctic Oscillation response to the 1991 Mount Pinatubo eruption: Effects of volcanic aerosols and ozone depletion, J. Geophys. Res., 107, 1–16, 2002. Stenchikov, G., Hamilton, K., Robock, A., Ramaswamy, V., and Schwarzkopf, M. D.: Arctic Oscillation response to the 1991 Pinatubo eruption in the SKYHI general circulation model with a realistic quasi-biennial oscillation, J. Geophys. Res., 109, 2004. Thomas, M. A., Timmreck, C., Giorgetta, M. A., Graf, H.-F., and Stenchikov, G.: Simulation of the climate impact of Mt Pinatubo eruption using ECHAM5 – Part 1: Sensitivity to the modes of atmospheric circulation and boundary conditions, Atmos. Chem. Phys., 9, 757–769, 2009. Trepte, C. R. and Hitchman, M. H.: Tropical stratospheric circulation deduced from satellite aerosol data, Nature, 355, 626–628, 1992. Trepte, C. R., Veiga, R. E., and McCormick, M. P.: The poleward dispersal of Mount Pinatubo volcanic aerosol, J. Geophys. Res., 98, 18563–18573, 1993. Untch, A.: A simulation of the quasi-biennial oscilaltion with the ECMWF model, Research Activities in Atmospheric and Ocean Modelling, WMO, 626–627, 1998. Wallace, J. M., Panetta, R. L., and Estberg, J.: Representation of the equatorial stratospheric quasi-biennial oscillation in EOF phase space, J Atmos. Sci., 50, 1751–1762, 1993. Yasunari, T.: A possible link of the QBOs between the stratosphere, troposphere and sea surface temperature in the tropics, J. Meteorol. Soc. Jpn., 67, 483–493, 1989.