ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-9-6109-2009 The climatic effects of the direct injection of water vapour into the stratosphere by large volcanic eruptions Joshi M. M. 1 Jones G. S. 2 NCAS Climate, University of Reading, UK Hadley Centre for Climate Change, Met Office, UK 25 08 2009 9 16 6109 6118 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/9/6109/2009/acp-9-6109-2009.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/9/6109/2009/acp-9-6109-2009.pdf

We describe a novel mechanism that can significantly lower the amplitude of the climatic response to certain large volcanic eruptions and examine its impact with a coupled ocean-atmosphere climate model. If sufficiently large amounts of water vapour enter the stratosphere, a climatically significant amount of water vapour can be left over in the lower stratosphere after the eruption, even after sulphate aerosol formation. This excess stratospheric humidity warms the tropospheric climate, and acts to balance the climatic cooling induced by the volcanic aerosol, especially because the humidity anomaly lasts for a period that is longer than the residence time of aerosol in the stratosphere. In particular, northern hemisphere high latitude cooling is reduced in magnitude. We discuss this mechanism in the context of the discrepancy between the observed and modelled cooling following the Krakatau eruption in 1883. We hypothesize that moist coignimbrite plumes caused by pyroclastic flows travelling over ocean rather than land, resulting from an eruption close enough to the ocean, might provide the additional source of stratospheric water vapour.

 References Angell, J. K.: Impact of El Niño on the delineation of tropospheric cooling due to volcanic eruptions, J. Geophys. Res., 93, 3697–3704, 1988. Bekki, S., Pyle, J. A., Zhong, W., Toumi, R., Haigh, J. D., and Pyle, D. M.: The role of microphysical and chemical processes in prolonging the climate forcing of the Toba eruption, Geophys. Res. Lett., 23(19), 2669–2672, 1996. Brohan, P., Kennedy, J. J., Harris, I., Tett, S. F. B., and Jones, P. D.: Uncertainty estimates in regional and global observed temperature changes: a new dataset from 1850, J. Geophys. Res., 111, D12106, doi:10.1029/2005JD006548, 2006. Carey, S., Sigurdsson, H., Mandeville, C., and Bronto, S.: Pyroclastic flows and surges over water: an example from the 1883 Krakatau eruption, B. Volcanol., 57(7), 493–511, 1996. Dall Amico, M., Gray, L. J., Rosenlof, K. H., Scaife, A. A., Shine, K. P., and Stott, P. A.: Stratospheric temperature trends: impact of ozone variability and the QBO, J. Climate, in press, 2009. Dartevelle, S., Ernst, G. G. J., Stix, J., and Bernard, A.: Origin of the Mount Pinatubo climactic eruption cloud: implications for volcanic hazards and atmospheric impacts, Geology, 30, 663–666, 2002. Forster, P. M. de F. and Shine, K. P.: Assessing the climate impact of trends in stratospheric water vapour, Geophys. Res. Lett., 29(6), 1086, doi:10.1029/2001GL013909, 2002. Forster, P. M. de F. and Taylor, K. E.: Climate Forcings and Climate Sensitivities Diagnosed from Coupled Climate Model Integrations, J. Climate, 19, 6181–6194, 2006. Francis, P. and Self, S.: The eruption of Krakatau, Sci. Am., 249, 146–159, 1983. Francis, P.: Volcanoes: a planetary perspective, Clarendon press, Oxford, 2000. Glaze, L. S., Baloga, S. M., and Wilson, L.: Transport of atmospheric water vapor by volcanic eruption columns, J. Geophys. Res., 102, 6099–6108, 1997. Gleckler, P. J., AchutaRao, K., Gregory, J. M., Santer, B. D., Taylor, K. E., and Wigley, T. M. L.: Krakatau lives: The effect of volcanic eruptions on ocean heat content and thermal expansion, Geophys. Res. Lett., 33, L17702, doi:10.1029/2006GL026771, 2006. Hall, T. M. and Waugh, D. W.: Timescales for the stratospheric circulation derived from tracers, J. Geophys. Res., 102, 8991–9001, 1997. Hansen, J., Sato, M., Ruedy, R., et al.: Climate simulations for 1880–2003 with GISS modelE, Clim. Dynam., 29, 661–696, 2007. Huang, T. Y. W. and Smith, A. K.: The Mesospheric Diabatic Circulation and the Parameterized Thermal Effect of Gravity Wave Breaking on the Circulation, J. Atmos. Sci., 48, 1093–1111, 1991. Johns, T. C., Durman, C. F., Banks, H. T., et al.: The new Hadley Centre climate model HadGEM1: Evaluation of coupled simulations, J. Climate, 19, 1327–1353, 2006. Jones, G. S., Stott, P. A., and Christidis, N.: Human contribution to rapidly increasing frequency of very warm Northern Hemisphere summers, J. Geophys. Res., 113, D02109, doi:10.1029/2007JD008914, 2008. Joshi, M. M. and Shine, K. P.: A GCM study of volcanic eruptions as a cause of increased stratospheric water vapour, J. Climate, 16, 3525–3534, 2003. Joshi, M. M., Charlton, A. J., and Scaife, A. A.: On the influence of stratospheric water vapour changes on the tropospheric circulation, Geophys. Res. Lett., 33, L09806, doi:10.1029/2006GL025983, 2006. Knutson, T. R., Delworth, T. L., Dixon, K. W., Held, I. M., Lu, J., Ramaswamy, V., Schwarzkopf, M. D., Stenchikov, G., and Stouffer, R. J.: Assessment of twentieth-century regional surface temperature trends using the GFDL CM2 coupled models, J. Climate, 19, 1624–1651, 2006. Mann, M. E., Bradley, R., Hughes, M., et al.: Global Temperature Patterns in Past Centuries: An Interactive Presentation, IGBP Pages/World Data Center for Paleoclimatology Data Contribution Series #2000-075, NOAA/NGDC Paleoclimatology Program, Boulder CO, USA, 2000. Martin, G. M., Ringer, M. A., Pope, V. D., Jones, A., Dearden, C., and Hinton, T. J.: The Physical Properties of the Atmosphere in the New Hadley Centre Global Environmental Model (HadGEM1). Part I: Model Description and Global Climatology, J. Climate, 19, 1274–1301, 2006. Miles, G. M., Grainger, R. G., and Highwood, E. J.: The significance of volcanic eruption strength and frequency for climate, Q. J. Roy. Meteor. Soc., 130, 2361–2374, 2004. Nedoluha, G. E., Bevilacqua, R. M., Gomez, R. M., Siskind, D. E., Hicks, B. C., Russell, J. M., and Connor, B. J.: Increases in middle atmosphere water vapor as observed by the Halogen Occultation Experiment and the ground-based Water Vapor Millimeter-wave Spectrometer from 1991 to 1997, J. Geophys. Res., 103, 3531–3543, 1998. Pitari, G. and Mancini, E.: Short term climatic impact of the 1991 volcanic eruption of Mt Pinatubo and effects on atmospheric tracers, Nat. Hazards Earth Syst. Sci., 2, 91–108, 2002. Randall, D. A., Wood, R. A., Bony, S., Colman, R., Fichefet, T., Fyfe, J., Kattsov, V., Pitman, A., Shukla, J., Srinivasan, J., Stouffer, R. J., Sumi, A., and Taylor, K. E.: Climate Models and Their Evaluation, in: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Averyt, K. B., Tignor, M., and Miller, H. L., Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 2007. Ramachandran, S., Ramaswamy, V., Stenchikov, G. L., and Robock, A.: Radiative impacts of the Mt Pinatubo volcanic eruption: Lower stratospheric response, J. Geophys. Res., 105, 24 409–24 429, 2000. Rayner, N. A., Brohan, P., Parker, D. E., Folland, C. K., Kennedy, J. J., Vanicek, M., Ansell, T., and Tett, S. F. B.: Improved analyses of changes and uncertainties in sea surface temperature measured in situ since the mid-nineteenth century: the HadSST2 data set, J. Climate, 19, 446–469, 2006. Robock, A.: Volcanic Eruptions and climate, Rev. Geophys., 38, 191–219, 2000. Sato, M., Hansen, J. E., McCormick, M. P., and Pollack, J. B.: Stratospheric aerosol optical depths, 1850–1990, J. Geophys. Res., 98, 22 987–22 994, 1993. Scaillet, B., Luhr, J., and Carroll, M. R.: Petrological and Volcanological constraints on volcanic sulfur emissions to the atmosphere, in Volcanism and the Earth's atmosphere, Geophysical monograph, 19, 11–40, 2003. Schroder, W.: Were noctilucent clouds caused by the Krakatau eruption? A case study of the research problems before 1885, B. Am. Meteorol. Soc., 80, 2081–2085, 1999. Scott, W. E., Hoblitt, R. P., Torres, R. C., Self, S., Martinez, M. L., and Nillos, Jr., T. : Pyroclastic flows of the June 15, 1991, climactic eruption of Mount Pinatubo, in: Fire and Mud: Eruptions and Lahars of Mount Pinatubo, Philippines, edited by: Newhall, C. G. and Punongbayan, R. S., Quezon City, Philippines: Philippine Inst. Volc. Seism., and Seattle: Univ. Wash. Press, 545–570, 1996. Self, S. and Rampino, M. R.: The 1883 eruption of Krakatau, Nature, 294, 699–704, 1981. Stenchikov, G., Hamilton, K., Stouffer, R. J., Robock, A., Ramaswamy, V., Santer, B., and Graf, H. F.: Arctic Oscillation response to volcanic eruptions in the IPCC AR4 climate models, J. Geophys. Res., 111, D07107, doi:10.1029/2005JD006286, 2006. Stott, P. A., Jones, G. S., Lowe, J. A., Thorne, P., Durman, C., Johns, T. C. and Thelen, J. C.: Transient simulations of HadGEM1 using historic and SRES scenarios, J. Climate, 19, 2763–2782, 2006. Waugh, D. W. and Hall, T. M.: Age of stratospheric air: theory, observations and models, Rev. Geophys., 40(4), 1010, doi:10.1029/2000RG000101, 2002. Woods, A. W. and Wohletz, K.: Dimensions and dynamics of co-ignimbrite eruption columns, Nature, 350, 225–227, 1991.