A Model of Intra-seasonal Oscillations in the Earth atmosphere
  We suggest a way of rationalizing an intra-seasonal oscillations (IOs) of the Earth atmospheric flow as four meteorological relevant triads of interacting planetary waves, isolated from the system of all the rest planetary waves.   Our model is independent of the topography (mountains, etc.) and gives a natural explanation of IOs both in the North and South Hemispheres. Spherical planetary waves are an example of a wave mesoscopic system obeying discrete resonances that also appears in other areas of physics. 
Elena Kartashova and Victor S. L'vov (RISC, J.Kepler University, Linz,   Austria and Chem.-Phys Dept., The Weizmann Institut...