The physics of turbulent atmospheric motions over a spherical planet will be investigated numerically by means of an in-house spectral code. Compared to planar analyses, spherical simulations do not impose artificial boundary constrains due to the numerical approach and, therefore, provide the perfect test case for two-dimensional turbulence studies. Basis functions composed by spherical harmonics will be used in the spectral code by implementing transform methods developed in the last ten years by several research groups around the world (Max Planck Institute, CNRS, ECMWF, for instance). The in- house spectral code will be developed around the transform method with special focus on accuracy and reliability of the results, with validation from actual atmospheric observations on Earth and other solar planets. Two-simulations are planned to provide answers to the organisation of small and large structures in the atmosphere of spherical planets, how the largest planetary scales evolve and exchange energy and enstrophy to smaller scales until three-dimensional turbulence is initiated.