Intraseasonal variability in the IAS and Its Representation in Models

This talk will review observations of intraseasonal variability (ISV) in the IAS region, including its impact on tropical cyclones and tropical synoptic disturbances. Our current understanding of the regulatory mechanisms for ISV in this region will be discussed, as derived from observational diagnosis and process modeling. This discussion will include that of local destabilization mechanisms and remote control by variability associated with the Madden-Julian oscillation. The ability of climate and forecasting models to capture the leading intraseasonal modes of variability in this region will be presented, including a process-oriented diagnosis based on the vertically-integrated moist static energy budget that highlights reasons for model bias and possible directions for improving the simulation of ISV.