The Horizontal Kinetic Energy Spectrum and Spectral Budget Simulated by a High-Resolution Troposphere–Stratosphere–Mesosphere GCM

Abstract

Abstract Horizontal kinetic energy spectra simulated by high-resolution versions of the Geophysical Fluid Dynamics Laboratory SKYHI middle-atmosphere general circulation model are examined. The model versions considered resolve heights between the ground and ∼80 km, and the horizontal grid spacing of the highest-resolution version is about 35 km. Tropospheric kinetic energy spectra show the familiar ∼−3 power-law dependence on horizontal wavenumber for wavelengths between about 5000 and 500 km and have a slope of ∼−5/3 at smaller wavelengths. Qualitatively similar behavior is seen in the stratosphere and mesosphere, but the wavelength marking the transition to the shallow regime increases with height, taking a value of ∼2000 km in the stratosphere and ∼4000 km in the mesosphere. The global spectral kinetic energy budget for various height ranges is computed as a function of total horizontal wavenumber. Contributions to the kinetic energy tendency from nonlinear advective processes, from conversion of avai...