ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-9-4329-2009 Stratospheric warming in Southern Hemisphere high latitudes since 1979 Hu Y. 1 Fu Q. 2 Department of Atmospheric Sciences, Peking University, Beijing, China Department of Atmospheric Sciences, University of Washington, Seattle, USA 03 07 2009 9 13 4329 4340 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/9/4329/2009/acp-9-4329-2009.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/9/4329/2009/acp-9-4329-2009.pdf

In the present study, we show evidence of significant stratospheric warming over Southern Hemisphere high latitudes and large portions of the Antarctic polar region in winter and spring seasons, with a maximum warming of 7–8°C in September and October, using satellite Microwave Sounding Unit observations for 1979–2006. It is found that this warming is associated with increasing wave activity from the troposphere into the stratosphere, suggesting that the warming is caused by enhanced wave-driven adiabatic heating. We show that the stratospheric warming in Southern Hemisphere high latitudes has close correlations with sea surface temperature (SST) increases, and that general circulation model simulations forced with observed time-varying SSTs reproduce similar warming trend patterns in the Antarctic stratosphere. The simulated stratospheric warming is closely related to increasing wave activity in the Southern Hemisphere. These findings suggest that the stratospheric warming is likely induced by SST warming. As SST warming continues as a consequence of greenhouse gas increases due to anthropogenic activity, the stratospheric warming would also continue, which has important implications to the recovery of the Antarctic ozone hole.

 References Andrews, D. G., Holton, J. R., and Leovy, C. B.: Middle Atmosphere Dynamics, Academic Press, New York, USA, 489 pp., 1987. Butchart, N. and Scaife, A. A.: Removal of chlorouorocarbons by increased mass exchange between the stratosphere and troposphere in a changing climate, Nature, 410, 799–802, 2001. Butchart, N., Scaife, A. A., Bourqui, M., et al.: Simulations of anthropogenic change in the strength of the Brewer–Dobson circulation, Clim. Dyn., 27, 727–741, 2006. Eichelberger, S. J. and Hartmann, D. L.: Changes in the strength of the Brewer-Dobson circulation in a simple AGCM, Geophys. Res. Lett., 32, L15807, doi:10.1029/2005GL022924, 2005. Fischer, A. M., Shindell, D. T., Winter, B., et al.: Stratospheric winter climate response to ENSO in three chemistry-climate models, Geophys. Res. Lett., 35, L13819, doi:10.1029/2008GL034289, 2008. Fusco, A. and Salby M. L.: Interannual variations of total ozone and their relationship to variations of planetary wave activity, J. Climate, 12, 1619–1629, 1999. Hoerling, M. P., Hurrell, J. W., and Xu, T.: Tropical origins for recent North Atlantic climate change, Science, 292, 90–92, 2001. Hoerling, M. P., Hurrell, J. W., Xu, T., Bates, G. T., and Phillips, A. S.: Twentieth century North Atlantic climate change. Part II: Understanding the effect of Indian Ocean warming, Climate Dyn., 23, 391–405, 2004. Holton, J. R., Haynes, P. H., McIntyre, M. E., et al.: Stratosphere-troposphere exchange, Rev. Geophys., 33, 403–439, 1995. Hu, Y. and Tung, K.: Interannual and decadal variations of planetary wave activity, stratospheric cooling, and Northern Hemisphere annular mode, J. Clim., 15, 1659–1673, 2002. Hu, Y. and Tung, K.: Possible ozone-induced long-term changes in planetary wave activity in late winter, J. Clim., 16, 3027–3038, 2003. Hu, Y., Tung, K., and Liu, J.: A closer comparison of early and late winter atmospheric trends in the Southern Hemisphere, J. Clim., 18, 2924–2936, 2005. Hu, Y. and Pan, L.: Arctic stratospheric winter warming forced by observed SSTs, Geophys. Res. Lett., 36, L11707, doi:10.1029/2009GL037832, 2009. Hurrell, J. W. and Loon, H.: A modulation of the atmospheric annual cycle in the Southern Hemisphere, Tellus, 46A, 325–338, 1994. IPCC: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Changes, edited by: Solomon, S., Qin, D., Manning, M., et al., Cambridge University Press, Cambridge, UK, 996 pp., 2007. Johanson, C. M. and Fu, Q.: Robustness of tropospheric temperature trends from MSU channels 2 and 4, J. Clim., 19, 4234–4242, 2006. Johanson, C. M. and Fu, Q.: Antarctic atmospheric temperature trend patterns from satellite observations, Geophys. Res. Lett., 34, L12703, doi:10.1029/2006GL029108, 2007. Kalnay, E., Kanamitsu, M., Kistler, R. et al.: The NCEP/NCAR 40-year reanalysis project. Bull. Am. Meteorol. Soc., 77, 437-471, 1996. Kistler, R., Kalnay, E., Collins, W., et al.: The NCEP-NCAR 50-year reanalysis: Monthly means CD-ROM and documentation, B. Am. Meteor. Soc., 82, 247–267, 2001. Knutson, T. R. and Manabe, S.: Model assessment of decadal variability and trends in the tropical Pacific ocean, J. Clim., 11, 2273–2296, 1998. Krüger, K., Naujokat, B., and Labitzke, K.: The Unusual Midwinter Warming in the Southern Hemisphere Stratosphere 2002: A Comparison to Northern Hemisphere Phenomena, J. Atmos. Sci., 62, 603–613, 2005. Langematz, U., Kunze, M., Krüger, K., Labitzke, K., and Roff, G. L.: Thermal and dynamical changes of the stratosphere since 1979 and their link to ozone and CO<sub>2</sub> changes, J. Geophys. Res., 108, 4027, doi:10.1029/2002JD002069, 2003. Lau, N.-C., Leetmaa, A., and Nath, M. J.: Influences of ENSO-induced Indo-Western Pacific SST anomalies on extratropical atmospheric variability during the boreal summer, J. Clim., 18, 2292–2942, 2005. Lau, N.-C., Leetmaa, A., and Nath, M. J.: Attribution of atmospheric variations in the 1997–2003 period to SST anomalies in the Pacific and Indian Ocean basins, J. Clim., 19, 3607–3628, 2006. Lin, P., Fu, Q., Solomon, S., and Wallace, J. M.: Temperature trend patterns in Southern Hemisphere high latitudes: novel indicators of stratospheric change. J. Clim., in press, 2009. Mears, C. A., Schabel, M. C., and Wentz, F. J.: A reanalysis of the MSU channel 2 tropospheric temperature record, J. Clim., 16, 3650–3664, 2003. Nishii, K. and Nakamura, H.: Tropospheric influence on the diminished Antarctic ozone hole in September 2002, Geophys. Res. Lett., 31, L16103, doi:10.1029/2004GL019532, 2004. Ramaswamy, V., Schwarzkopf, M. D., and Randel, W. J.: Fingerprint of ozone depletion in the spatial and temporal pattern of recent lower stratospheric cooling, Nature, 382, 616–618, 1996. Ramaswamy, V., Chanin, M.-L., Angell, J., et al.: Stratospheric temperature trends: Observations and model simulations, Rev. Geophys., 39, 71–122, 2001. Randel, W. J. and Wu F.: Cooling of the Arctic and Antarctic polar stratosphere due to ozone depletion, J. Clim., 12, 1467–1479, 1999. Randel, W.: The seasonal evolution of planetary waves in the Southern Hemisphere stratosphere and troposphere, Q. J. Roy. Meteor. Soc., 114, 1385–1409, 1988. Rayner, N. A., Parker, D. E., Horton, E. B., et al.: Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century, J. Geophys. Res., 108, 4407, doi:10.1029/2002JD002670, 2003. Schmidt, G. A., Ruedy, R., Hansen, J. E., et al.: Present day atmospheric simulations using satellite and re-analysis data, J. Clim., 19, 153, 153–192, 2006. Shindell, D. T. and Schmidt, G. A.: Southern Hemisphere climate response to ozone changes and greenhouse gas increases, Geophys. Res. Lett., 31, L18209, doi:10.1029/2004GL020724, 2004. Solomon, S.: Stratospheric ozone depletion: a review of concepts and history, Rev. Geophys., 37, 275–316, 1999. Thompson, D. W. J. and Solomon, S.: Interpretation of recent Southern Hemisphere climate change, Science, 296, 895–899, 2002. Turner, J., Lachlan-Cope, T. A., Colwell, S. R., Marshall, G. J., and Connolley, W. M.: Significant warming of the Antarctic winter troposphere, Science, 311, 1914–1917, 2006. Varotsos, C.: The Extraordinary Events of the Major, Sudden Stratospheric Warming, the Diminutive Antarctic Ozone Hole, and its Split in 2002, Environ. Sci. Pollut. Res., 11, 405–411, 2004. Weatherhead, E. C. and Andersen, S. B.: The search for signs of recovery of the ozone layer, Nature, 441, 39–45, 2006. WMO (World Meteorological Organization): Scientific Assessment of Ozone Depletion: 2006, Global Ozone Research and Monitoring Project, Report No. 50, Geneva, Switzerland, 572 pp., 2007.