Earth’s atmosphere covers more than 500 million square kilometers, yet most of its mass is confined to a tropospheric region only 10 km thick. Large-scale turbulence in the fast-rotating troposphere is therefore essentially two dimensional, but so far, theories have not been able to accurately account for the energy associated with this type of turbulent flow.
In a paper appearing in Physical Review Letters, David Dritschel from the University of St. Andrews in the United Kingdom, Georg Gottwald at the University of Sydney, Australia, and colleagues present a consistent model that unifies spatial and temporal theories of vortices in two-dimensional turbulent flow. The model, which is based on few assumptions and does not rely on any empirical fitting to data, describes how the density of vortices scales with their area and time. Gottwald et al. use their model to obtain accurate energy spectra that are consistent with high-resolution numerical simulations. This scaling approach could reveal some of the mechanisms behind fascinating phenomena in turbulent air and water transport. – Deniz van Heijnsbergen