A nonlinear perspective on the dynamics of the MJO: Idealized large-eddy simulations

Diabatic processes related to tropical convection and two-way atmosphere-ocean interaction are hence generally believed to be crucial in explaining the origin of the MJO phenomenon. However, reliable deterministic forecasting of the MJO in global circulation models and understanding its mechanism remains unsatisfactory.

Here a different approach is taken, where the hypothesis is tested that eastward-propagating MJO-like structures originate fundamentally as a result of nonlinear (dry) Rossby wave dynamics. A laboratory-scale numerical model is constructed, where the generation of solitary structures is excited and maintained via zonally propagating meanders of the meridional boundaries of a zonally periodic β plane. The large-eddy simulations capture details of the formation of solitary structures and of their impact on the convective organization.