Publication: Nonlinearity of the combined warm ENSO and QBO effects on the Northern Hemisphere polar vortex in MAECHAM5 simulations
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2009-07-14
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American Geophysical Union
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The influence of the quasi-biennial oscillation (QBO) on the Northern Hemisphere (NH) polar vortex response to warm El Nino-Southern Oscillation (ENSO) events and the impact of the warm ENSO events on the QBO signal in the NH polar stratosphere have been analyzed using the Middle Atmosphere ECHAM5 model. The experiment setup was designed to include simulations of extended NH winter seasons for either strong easterly or strong westerly phases of the tropical QBO, forced with either sea surface temperatures (SSTs) from the strong ENSO event that occurred in 1997/1998 or with climatological SSTs. It has been found that the weakening and warming of the polar vortex associated with a warm ENSO are intensified at the end of the winter during both QBO phases. In addition, the westerly QBO phase delays the onset of the warm ENSO signal, while the easterly QBO phase advances it. Warm ENSO events also impact the extratropical signal of the QBO by intensifying ( weakening) the QBO effects in early ( late) winter. Therefore, it appears that during warm ENSO events the duration of QBO signal in the northern extratropics is shortened while its downward propagation accelerated. Our dynamical analysis has revealed that these results are due to changes in the background flow caused by the QBO combined with changes in the anomalous propagation and dissipation of extratropical waves generated by warm ENSO. In both cases, a nonlinear behavior in the response of the polar vortex is observed when both warm ENSO and the easterly phase of the QBO operate together. These results suggest that the Arctic polar vortex response to combined forcing factors, in our case warm ENSO and the QBO phenomena, is expected to be nonlinear also for other coexistent forcing factors able to affect the variability of the vortex in the stratosphere.
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© 2009 by the American Geophysical Union.
N. Calvo was supported by the visitor program of the Max Planck Institute for Meteorology in Hamburg, the Spanish Ministry of Education and Science, and the Fulbright Commission in Spain. The simulations described here were carried out on the NEC-SX6 computer at the German Climate Computing Center (DKRZ). We thank Rolando R. García and Daniel Marsh for their helpful comments and suggestions.
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Andrews, D. G., J. R. Holton, and C. B. Leovy (1987), Middle Atmosphere Dynamics, Int. Geophys. Ser, vol. 40, 489 pp., Elsevier, New York.
Baldwin, M. P., and D. O’Sullivan (1995), Stratospheric effects of ENSO-related tropospheric circulation anomalies, J. Clim., 8, 649 – 667, doi:10.1175/1520-0442(1995)008<0649:SEOERT>2.0.CO;2.
Calvo, N., M. A. Giorgetta, and C. Peña Ortiz (2007), Sensitivity of the boreal winter circulation in the middle atmosphere to the quasi-biennial oscillation in MAECHAM5 simulations, J. Geophys. Res., 112, D10124, doi:10.1029/2006JD007844.
Camp, C. D., and K. K. Tung (2007), The influence of the solar cycle and QBO on the late-winter stratospheric polar vortex, J. Atmos. Sci., 64, 1267 – 1283, doi:10.1175/JAS3883.1.
Charney, J. G., and P. G. Drazin (1961), Propagation of planetary-scale disturbances from the lower into the upper atmosphere, J. Geophys. Res., 66, 83 – 109, doi:10.1029/JZ066i001p00083.
Edmon, H. J., Jr., B. J. Hoskins, and M. E. McIntyre (1980), Eliassen-Palm cross sections for the troposphere, J. Atmos. Sci., 37, 2600 – 2616, doi:10.1175/1520-0469(1980)037<2600:EPCSFT>2.0.CO;2.
García Herrera, R., N. Calvo, R. García, and M. Giorgetta (2006), Propagation of ENSO temperature signals into the middle atmosphere: A comparison of two general circulation models and ERA-40 reanalysis data, J. Geophys. Res., 111, D06101, doi:10.1029/2005JD006061.
Garfinkel, C. I., and D. L. Hartmann (2007), 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.
Giorgetta, M. A., E. Manzini, and E. Roeckner (2002), Forcing of the quasibiennial oscillation from a broad spectrum of atmospheric waves, Geophys. Res. Lett., 29(8), 1245, doi:10.1029/2002GL014756.
Giorgetta, M. A., E. Manzini, E. Roeckner, M. Esch, and L. Bengtsson (2006), Climatology and forcing of the quasi-biennial oscillation in the MAECAM5 model, J. Clim., 19, 3882 – 3901, doi:10.1175/JCLI3830.1.
Hamilton, K. (1993), An examination of observed Southern Oscillation effects in the Northern Hemisphere stratosphere, J. Atmos. Sci., 50, 3468 – 3473, doi:10.1175/1520-0469(1993)050<3468:AEOOSO>2.0.CO;2
Holton, J. R., and H. C. Tan (1980), The influence of the equatorial quasibiennial oscillation on the global circulation at 50 mb, J. Atmos. Sci., 37, 2200 – 2208, doi:10.1175 1520-0469(1980)037<2200:TIOTEQ>2.0.CO;2
Holton, J. R., and H.-C. Tan (1982), The quasi-biennial oscillation in the Northern Hemisphere lower stratosphere, J. Meteorol. Soc. Jpn., 60, 140 – 148.
Manzini, E., M. A. Giorgetta, M. Esch, L. Kornblueh, and E. Roeckner (2006), The influence of sea surface temperatures on the northern winter stratosphere: Ensemble simulations with the MAECHAM5 model, J. Clim., 19, 3863 – 3881, doi:10.1175/JCLI3826.1.
Naito, Y., and I. Hirota (1997), Interannual variability of the northern winter stratospheric circulation related to the QBO and the solar cycle, J. Meteorol. Soc. Jpn., 75, 925 – 937.
Roeckner, E., et al. (2003), The atmospheric general circulation model ECHAM5: Part 1, MPI-Rep. 349, 127 pp., Max Planck Inst. for Meteorol., Hamburg, Germany.
Roeckner, E., R. Brokopf, M. Esch, M. Giorgetta, S. Hagemann, L. Kornblueh, E. Manzini, U. Schlese, and U. Schulzweida (2006), Sensitivity of simulated climate to horizontal and vertical resolution in the ECHAM5 atmosphere model, J. Clim., 19, 3771 – 3791, doi:10.1175/JCLI3824.1.
Sassi, F., D. Kinnison, B. A. Boville, R. R. Garcia, and R. Roble (2004), The effects of ENSO on the dynamical, therman and chemical structure of the middle atmosphere, J. Geophys. Res., 109, D17108, doi:10.1029/2003JD004434.
van Loon, H., and K. Labitzke (1987), The Southern Oscillation: Part V: The anomalies in the lower stratosphere of the Northern Hemisphere in winter and a comparison with the quasi-biennial oscillation, Mon. Weather Rev., 109, 149 – 155.
Wallace, J. M., and F.-C. Chang (1982), Interannual variability of the wintertime polar vortex in the Northern Hemisphere middle stratosphere, J. Meteorol. Soc. Jpn., 60, 149 – 155.
Wei, K., W. Chen, and R. Huang (2007), Association of tropical Pacific sea surface temperatures with the stratospheric Holton-Tan relationship in the Northern Hemisphere winter, Geophys. Res. Lett., 34, L16814, doi:10.1029/2007GL030478.