The horizontal energy spectra and cascade processes in rotating stratified turbulence

Numerical experiments on rotating stratified turbulence are conducted with a high-resolution model to investigate the horizontal energy spectrum seen in the troposphere. Both the k(H)(-3) and k(H)(-5/3) regimes observed in the atmosphere are reproduced in our experiments by downscale cascade from the synoptic scale at which forcing is given. The transition scale between the two regimes becomes smaller with the Rossby deformation radius NH/f. The energy associated with divergent motion is predominant in the k(H)(-5/3) region and the triads composed of one vortical and two divergent modes mainly contribute to energy transfer to the higher wavenumbers.