MASS Seminar - Chidong Zhang (Miami)
Date Time Location
May 9th, 2011 12:00pm-1:00pm 54-915
Potential Vorticity of the Madden-Julian Oscillation and Equatorial Waves

Potential Vorticity (PV) is used as a diagnostic tool to explore the three-dimensional dynamical and thermodynamical structure of the Madden-Julian Oscillation (MJO) in comparison to equatorial waves. Structures of PV and diabatic heating of the MJO are distinct from those of the equatorial Kelvin and Rossby waves. PV generation of the MJO is dominated by MJO diabatic heating acting on planetary vorticity and interaction between diabatic heating and relative vorticity of non-MJO perturbations. In this latter MJO PV generation process, no identifiable role by the equatorial Kelvin and Rossby waves is found. From a PV point of view, thus, the MJO is maintained by a combination of self-sustaining and stochastic scale-interaction processes independent of the equatorial Kelvin and Rossby waves. Over the tropical Indian Ocean, main features in PV generation of the MJO during its initiation include strong pre-existing anticyclonic PV associated with negative anomalies of diabatic heating prior to the emergence of positive anomalies of diabatic heating. This suggests a possible precursor for prediction of MJO initiation.


http://metofis.rsmas.miami.edu/~czhang/