Information flow between MJO-related waves: a network approach on the wave space
Institute of Astronomy, Geophysics and Atmospheric Sciences, University of Sao Paulo-Rua do Matão, 1226-Cidade Universitária, São Paulo, SP, Brazil
2 Brain Institute-Av. Nascimento de Castro, 2155, 59056-450, Natal, RN, Brazil
3 Department of Mathematical Sciences, Durham University, Stockton Road, DH1 3LE, Durham, UK
Accepted: 23 April 2021
Published online: 5 June 2021
The complex network approach has proved to be a valuable tool for climate and atmospheric sciences in recent years. Here, we show an application of causality ideas in complex networks to infer properties of equatorial wave interactions associated with the Madden–Julian Oscillation (MJO), the dominant component of the atmospheric system on intraseasonal timescales in the equatorial region. We use the normal mode function approach to obtain the time series of baroclinic Kelvin and Rossby mode energies, since both of these wave modes are known to play an important role in the MJO dynamics. The partial directed coherence method reveals the structure of the interaction among those modes and shows that the Kelvin mode is the main driver of the MJO system, transferring energy to the Rossby modes. Investigation on the Kelvin mode information source might help evaluating the state-of-the-art of MJO theories.
© The Author(s), under exclusive licence to EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature 2021