Group seminar on 18. January, 14:15 CET
The Madden-Julian Oscillation and the Skeleton Mode
Sam Stechmann
The Madden-Julian Oscillation (MJO) is a planetary-scale wave envelope of tropical clouds and precipitation. It is the dominant component of tropical weather and climate on oscillation time scales of 30-60 days, and it modulates tropical cyclones and impacts the active and break phases of monsoons. Despite its importance, the MJO remains a challenging phenomenon to simulate in climate models, and its underlying mechanisms are still under debate. In this presentation, a model for the MJO (the MJO Skeleton Model) is described. Three aspects in particular are: nonlinear traveling wave solutions, a stochastic version of the model, and a method for identifying the MJO in observational data. Key aspects of the observed MJO will be demonstrated in the model, including its phase speed, structure, and statistics. Lastly, we will discuss these results in the context of subseasonal forecasting: the ability to make predictions not only a few days in advance but weeks or even months in advance, for which the MJO will play an important role.