Diversity of the Global Teleconnections Associated with the Madden-Julian Oscillation

A recent study has revealed that the Madden Julian oscillation (MJO) during boreal winter exhibits diverse propagation patterns that consist of four archetypes: standing MJO, jumping MJO, slow eastward propagating MJO, and fast eastward propagating MJO. This study has explored the diversity of teleconnection associated with these four MJO groups. The results reveal that each MJO group corresponds to distinct global teleconnections, manifested as diverse upper-tropospheric Rossby wave train patterns. Overall, the teleconnections in the fast and slow MIO are similar to those in the canonical MJO constructed by the real-time multivariate MJO (RMM) indices, while the teleconnections in the jumping and standing MJO generally lose similarities to those in the canonical MJO. The causes of this diversity are investigated using a linearized potential vorticity equation. The various MIO tropical heating patterns in different MJO groups are the main cause of the diverse MJO teleconnections, as they induce assorted upper-level divergent flows that act as Rossby-wave sources through advecting the background potential vorticity. The variation of the Asian jet could affect the teleconnections over the Pacific jet exit region, but it plays an insignificant role in causing the diversity of global teleconnections. The numerical investigation with a linear baroclinic model shows that the teleconnections can be interpreted as linear responses to the MJO's diabatic heating to various degrees for different MIO groups, with the fast and slow MJO having higher linear skill than the jumping and standing MJO. The results have broad implications in the MJO's tropical-extratropical interactions and the associated impacts on global weather and climate.

Automated summary

A recent study found diverse propagation patterns of the Madden Julian oscillation (MJO) during boreal winter, with each pattern corresponding to distinct global teleconnections mainly due to the diversity of tropical heating patterns. The study suggests that the teleconnections in different MJO groups exhibit varying linear responses to the MJO's diabatic heating, with the fast and slow MJO showing higher linear skill compared to the jumping and standing MJO.