Articles | Volume 9, issue 22
Atmos. Chem. Phys., 9, 8935–8948, 2009
Atmos. Chem. Phys., 9, 8935–8948, 2009

  27 Nov 2009

27 Nov 2009

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

C. Cagnazzo1, E. Manzini1,2, N. Calvo3, A. Douglass4, H. Akiyoshi5, S. Bekki6, M. Chipperfield7, M. Dameris8, M. Deushi9, A. M. Fischer10,*, H. Garny8, A. Gettelman11, M. A. Giorgetta12, D. Plummer13, E. Rozanov10,15, T. G. Shepherd14, K. Shibata9, A. Stenke8, H. Struthers16,**, and W. Tian7 C. Cagnazzo et al.
  • 1Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna, Italy
  • 2Istituto Nazionale di Geofisica e Vulcanologia, Bologna, Italy
  • 3Dpto. Fisica de la Tierra II, Universidad Complutense de Madrid, Spain
  • 4NASA Goddard Space Flight Center, Greenbelt MD, USA
  • 5National Institute for Environmental Studies, Tsukuba, Japan
  • 6Service d'Aeronomie du CNRS, IPSL, Paris, France
  • 7School of Earth and Environment, University of Leeds, Leeds, UK
  • 8DLR-Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
  • 9Meteorological Research Institute, Tsukuba, Ibaraki 305-0052, Japan
  • 10Institute for Atmospheric and Climate Science, ETH Zürich, Zürich, Switzerland
  • 11National Center for Atmospheric Research, Boulder, Colorado, USA
  • 12Max Planck Institute for Meteorology, Hamburg, Germany
  • 13Environment Canada, Toronto, Ontario, Canada
  • 14Department of Physics, University of Toronto, Toronto, Ontario, Canada
  • 15Physical-Meteorological Observatory/World Radiation Center, Davos, Switzerland
  • 16National Institute of Water & Atmospheric Research, Auckland, New Zealand
  • *now at: Federal Office of Meteorology and Climatology MeteoSwiss, Zürich, Switzerland
  • **now at: ITM – Stockholms universitet, Stockholms, Sweden

Abstract. The connection between the El Niño 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° 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.

Final-revised paper