Kinetic energy spectrum of large-and mesoscale atmospheric processes

Abstract

Considerable attention has recently been focused on the distribution of atmospheric kinetic energy over the range of scales often referred to as the mesoscale. Despite the importance of the mesoscale range of wavelengths (10¹–10³ km) for dynamical analyses and for numerical weather prediction, there have been few measurements of the kinetic energy spectrum over this range. Here, we report the results of a new determination of the kinetic energy spectrum of winds near the tropopause level for the wavelength range 2.6–10⁴ km. This spectrum is based on wind measurements made on board airliners in routine commerical service. We find that the spectrum obeys a −5/3 power law dependence on wavenumber over the wavelength range ∼2.6–300 km and a −3 power law over the range 1,000–3,000 km. The spectral magnitudes of the zonal and meridional winds are very similar, especially over the −5/3 region.