The Role of Dry Dynamics in the MJO

Most recent theoretical studies of the MJO have argued that moisture-convection feedbacks are essential to explaining the existence of this planetary-scale phenomenon (e.g., the "moisture-mode" hypothesis). However, it is well known from observations that signals of the disturbance in circulation are not always coupled to convection, even over the Indo-Pacific warm pool region. While some might argue that these "dry" MJOs should be regarded as the convectively forced remnants of previous "moist" MJOs, I will present evidence in this talk to suggest a crucial role of dry planetary wave dynamics.