The Emerging and Terminating States of Madden-Julian Oscillation: Kinematics and Thermodynamics

In this talk, we continue the previous study using permutation entropy (PE) to detect local signs and timing of dynamical changes associated with the initiation and termination of the Madden-Julian oscillation (MJO) in the ERA-interim reanalysis from 1984 to 2005. It is noted that the PE is defined according to rank statistics and therefore is not affected by the magnitude of the fields from which it is calculated; therefore, it equalizes comparisons across signals in the tropical and extratropical latitudes. It was found that local signs of initiation in perturbation kinetic energy, temperature, and moisture fields were farther west and planetary-scale than expected for convection initiation over Indian Ocean, with signals over tropical and extratropical Africa and northeast Pacific. On the other hand, the northwest Atlantic, including the Carribeans, bore signals of the seasonal termination of the boreal-winter MJOs. We further ask the questions of what are the three-dimensional atmospheric states at these critical transitions, as well the physical interpretations of these states. Case studies during 1992-1993 TOGA-COARE and 2011-2012 DYNAMO periods will be detailed.