Articles | Volume 20, issue 11
Atmos. Chem. Phys., 20, 6541–6561, 2020
Atmos. Chem. Phys., 20, 6541–6561, 2020

Research article 05 Jun 2020

Research article | 05 Jun 2020

On the forcings of the unusual Quasi-Biennial Oscillation structure in February 2016

Haiyan Li et al.

Data sets

The ERA-40 re-analysis ( S. M. Uppala, P. W. Kållberg, A. J. Simmons, U. Andrae, V. D. Costa Bechtold, M. Fiorino, J. K. Gibson, J. Haseler, A. Hernandez, G. A. Kelly, X. Li, K. Onogi, S. Saarinen, N. Sokka, R. P. Allan, E. Andersson, K. Arpe, M. A. Balmaseda, A. C. M. Beljaars, L. Van, D. Berg, J. Bidlot, N. Bormann, S. Caires, F. Chevallier, A. Dethof, M. Dragosavac, M. Fisher, M. Fuentes, S. Hagemann, E. Hólm, B. J. Hoskins, L. Isaksen, P. A. E. M. Janssen, R. Jenne, A. P. Mcnally, J. Mahfouf, J. Morcrette, N. A. Rayner, R. W. Saunders, P. Simon, A. Sterl, K. E. Trenberth, A. Untch, D. Vasiljevic, P. Viterbo, and J. Woollen

NOAA Extended Reconstructed Sea Surface Temperature (SST) V4 NOAA, OAR, ESRL, and PSL

Description of a Complete (Interpolated) Outgoing Longwave Radiation Dataset ( B. Liebmann and C. A. Smith

Short summary
The QBO westerly phase was reversed by an unexpected easterly jet near 40 hPa and the westerly zonal wind lasted an unusually long time at 20 hPa during winter 2015/16. We find that quasi-stationary Rossby wave W1 and faster Rossby wave W2 propagating from the northern extratropics and a locally generated Rossby wave W3 were important contributors to the easterly jet at 40 hPa. Our results suggest that the unusual zonal wind structure at 20 hPa could be caused by enhanced Kelvin wave activity.
Final-revised paper