Title: Why are GCMs bad at simulating the MJO?
Abstract: Most General Circulation Models still have difficulties to simulate realistic Madden-Julian Oscillation events. Two leading hypotheses have been proposed to explain this widespread deficiency. The first one posits that the GCMs do not simulate a realistic vertical profile of diabatic heating associated with clouds and cloud envelopes. The second hypothesis considers that the GCMs are unable to simulate the large-scale, spatial organisation of convection necessary to initiate an MJO event because their parametrisations of convection lack the sub-grid and inter-grid processes that are essential to its development. The presentation will present studies that address questions inspired by these hypotheses: how do diabatic-heating profiles simulated by GCMs compare to observations? On what scales should we expect convection to organise?