Publication: Forcing mechanism of the seasonally asymmetric quasi-biennial oscillation secondary circulation in ERA-40 and MAECHAM5
Full text at PDC
Advisors (or tutors)
American Geophysical Union
The seasonality of the quasi-biennial oscillation (QBO) and its secondary circulation is analyzed in the European Reanalysis (ERA-40) and Middle Atmosphere European Centre Hamburg Model (MAECHAM5) general circulation model data sets through the multitaper method-singular value decomposition (MTM-SVD). In agreement with previous studies, the results reveal a strong seasonal dependence of the QBO secondary circulation. This is characterized by a two-cell structure symmetric about the equator during autumn and spring. However, anomalies strongly weaken in the summer hemisphere and strengthen in the winter hemisphere, leading to an asymmetric QBO secondary circulation characterized by a single-cell structure displaced into the winter hemisphere during the solstices. In ERA-40, this asymmetry is more pronounced during the northern than during the southern winter. These results provide the first observation of the QBO secondary circulation asymmetries in the ERA-40 reanalysis data set across the full stratosphere and the lower mesosphere, up to 0.1 hPa. The MTM-SVD reconstruction of the seasonal QBO signals in the residual circulation and the QBO signals in Eliassen Palm (EP) flux divergences suggest a particular mechanism for the seasonal asymmetries of the QBO secondary circulation and its extension across the midlatitudes. The analysis shows that the QBO modulates the EP flux in the winter hemispheric surf zone poleward of the QBO jets. The zonal wind forcing by EP flux divergence is transformed by the Coriolis effect into a meridional wind signal. The seasonality in the stratospheric EP flux and the hemispheric differences in planetary wave forcing cause the observed seasonality in the QBO secondary circulation and its hemispheric differences.
Copyright 2008 by the American Geophysical Union. This work was partly funded by the Spanish National Research Project TRODIM MEC-CGL2007-65891-C05-04-CLI.
Andrews, D. G., and M. E. McIntyre (1976), Planetary waves in horizontal and vertical shear: The generalized Eliassen-Palm relation and the mean zonal acceleration, J. Atmos. Sci., 33, 2031 – 2048. Andrews, D. G., J. R. Holton, and C. B. Leovy (1987), Middle Atmosphere Dynamics, 489 pp., Academic, San Diego, Calif. Baldwin, M. P., and L. J. Gray (2005), Tropical stratospheric winds in ECMWF ERA-40 reanalysis, rocketsonde data, and rawinsonde data, Geophys. Res. Lett., 32(9), L09806, doi:10.1029/2004GL022328. Baldwin, M. P., et al. (2001), The quasi-biennial oscillation, Rev. Geophys., 39, 179 – 229. Bengtsson, L., K. I. Hodges, and S. Hagemann (2004), Sensitivity of the ERA40 reanalysis to the observing system: Determination of the global atmospheric circulation from reduced observations, Tellus, 56A, 456 – 471. 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. Dunkerton, T. J. (1985), A two-dimensional model of the quasi-biennial oscillation, J. Atmos. Sci., 42, 1151 – 1160. Dunkerton, T. J. (1997), The role of gravity waves in the quasibiennial oscillation, J. Geophys. Res., 102, 26,053 – 26,076. Dunkerton, T. J., and D. P. Delisi (1985), Climatology of the equatorial lower stratosphere, J. Atmos. Sci., 42, 376 – 396. Dunkerton, T. J., and D. P. Delisi (1997), Interaction of the quasi-biennial oscillation and stratopause semiannual oscillation, J. Geophys. Res., 102, 26,107 – 26,116. Efron, B. (1990), More efficient bootstrap computations, J. Am. Stat. Assoc., 85(409), 79 – 89. García, R. R. (1987), On the mean meridional circulation of the middle atmosphere, J. Atmos. Sci., 44, 3599 – 3609. 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 MAECHAM5 model, J. Clim., 19(16), 3882 – 3901. Hamilton, K. (1998), Effects of an imposed quasi-biennial oscillation in a comprehensive troposphere-stratosphere-mesosphere general circulation model, J. Atmos. Sci., 55, 2393 – 2418. Haynes, P. H. (1998), The latitudinal structure of the quasi-biennial oscillation, Q. J. R. Meteorol. Soc., 124, 2645 – 2670. Holton, J. R. (1989), Influence of the annual cycle in meridional transport on the quasi-biennial oscillation in total ozone, J. Atmos. Sci., 46, 1434 – 1439. Holton, J. R., and H. C. Tan (1980), Influence of the equatorial quasibiennial oscillation on the global circulation at 50 Mb, J. Atmos. Sci., 37(10), 2200 – 2208. Huesmann, A. S., and M. H. Hitchman (2001), The stratospheric quasibiennial oscillation in the NCEP reanalyses: Climatological structures, J. Geophys. Res., 106, 11,859 – 11,874. Jones, D. B. A., H. R. Schneider, and M. B. McElroy (1998), Effects of the quasi-biennial oscillation on the zonally averaged transport of tracers, J. Geophys. Res., 103, 11,235 – 11,249. Kinnersley, J. S. (1999), On the seasonal asymmetry of the lower and middle latitude QBO circulation anomaly, J. Atmos. Sci., 56, 1140 – 1153. Kinnersley, J. S., and K. K. Tung (1999), Mechanisms for the extratropical QBO in circulation and ozone, J. Atmos. Sci., 56(12), 1942 – 1962. Lindzen, R. S., and J. R. Holton (1968), A theory of the quasi-biennial oscillation, J. Atmos. Sci., 25, 1095 – 1107. Mann, M. E., and J. Park (1999), Oscillatory patio-temporal signal detection in climate studies: A multiple-taper spectral domain approach, Adv. Geophys., 41, 1 – 131. 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. Pascoe, C. L., L. J. Gray, S. A. Crooks, M. N. Juckes, and M. P. Baldwin (2005), The quasi-biennial oscillation: Analysis using ERA-40 data, J. Geophys. Res., 110, D08105, doi:10.1029/2004JD004941. Plumb, R. A. (1984), The quasi-biennial oscillation, in Dynamics of the Middle Atmosphere, edited by J. R. Holton and T. Matsuno, pp. 217 – 251, Terra Sci., Tokyo, Japan. Plumb, R. A., and R. C. Bell (1982), A model of the quasi- biennial oscillation on an equatorial beta-plane, Q. J. R. Meteorol. Soc., 108, 335 – 352. Punge, H. J., and M. A. Giorgetta (2007), Differences between the QBO in the first and in the second half of the ERA-40 reanalysis, Atmos. Chem. Phys., 7, 599 – 608. Reed, R. J. (1964), A tentative model of the 26-month oscillation in tropical latitudes, Q. J. R. Meteorol. Soc., 90, 441 – 466. Ribera, P., D. Gallego, C. Peña Ortiz, L. Gimeno, R. García Herrera, E. Hernández, and N. Calvo (2003), The stratospheric QBO signal in the NCEP reanalysis 1958-2001, Geophys. Res. Lett., 30(13), 1691, doi:10.1029/2003GL017131. Ribera, P., C. Peña Ortiz, R. García Herrera, D. Gallego, L. Gimeno, and E. Hernández (2004), Detection of the secondary meridional circulation associated with the quasi-biennial oscillation, J. Geophys. Res., 109, D18112, doi: 10.1029/2003JD004363. Roeckner, E., et al. (2003), The atmospheric general circulation model ECHAM5. part 1, MPI-Rep. 349, 127 pp. 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. Ruzmaikin, A., J. Feynman, and X. Jiang (2005), Extratropical signature of the quasi-biennial oscillation, J. Geophys. Res., 110, D11111, doi:10.1029/2004JD005382. Takahashi, M. (1987), A two-dimensional numerical model of the quasibiennial oscillation, J. Meteorol. Soc. Jpn., 65, 523 – 535. Tung, K., and H. Yang (1994), Global QBO in circulation and ozone. part II: A simple mechanistic model, J. Atmos. Sci., 51, 2708 – 2721. Uppala, S. M., et al. (2005), The ERA-40 re-analysis, Q. J. R. Meteorol. Soc., 131, 2961 – 3012, doi:10.1256/qj.04.176.