Seasonality and Regionality of the Madden-Julian Oscillation, Kelvin Wave, and Equatorial Rossby Wave – Masunaga

by Joe Archive on February 15, 2008

a href=”http://ams.allenpress.com/perlserv/?request=get-abstractamp;doi=10.1175%2FJAS3783.1″JAS 64-4400 (astract)/abr /br /Masunaga uses frequency and wavenumber filtered data to look at the Kelvin, Equatorial Rossby and Madden-Julian waves in the outgoing long-wave radiation (OLR) record. By Fourier transforming the record, selecting only the wavenumbers and frequencies that correspond to waves of interest and transforming back, Masunaga produces time series of the various wave types’ disturbances in the atmospheric convection. Using an algorithm to identify convective peaks in the filtered data, he then can track the convection centers of these waves as they propagate. He uses these to make composites of the flows around the the various waves (from reanalysis data), and to investigate how the ER and Kelvin waves (which are very close to their theoretical, dry profiles) interact with each other and the MJO, investigating how the first two might form a mechanism for exciting the third.br /br /From the observations, Masunaga speculates about the life cycle of the MJO:br /br /Starts with onset over the Indian Ocean, propagates to the east. In southern summer (DJF), the MJO convection center passes through the channel between Australia and Indonesia/New Guinea and deep into the pacific ocean.br /br /When an incoming Kelvin wave encounters an ER wave, these waves interact through off equatorial convergence in the boundary layer within the MJO envelope.br /br /This bit is interesting to me – If the observations that the Kelvin and ER waves can cause substantial BL convergence that could interact is correct, then it seems possible that the addition of terms like this to my model might allow the existence of a coupled Kelvin/ER mode that resembles the MJO.

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