Halting scale and energy equilibration in two-dimensional quasigeostrophic turbulence

Abstract

AbstractThe halting scale of the inverse energy cascade and the partition between kinetic and potential energy are considered for the case of forced quasigeostrophic turbulence in the regime of intermediate Rossby deformation length, for which the deformation length is comparable to the energy-containing scales of the flow. Phenomenological estimates for the halting scale and equilibrated energy of the forced–dissipative system with a simple representation of large-scale thermal damping are tested against numerical integrations and are found to poorly describe the numerically obtained dependence on damping coefficient; a modified scaling law is proposed that more accurately describes the dependence. The scale-selective nature of the damping leads to a large-scale spectral bottleneck that steepens the energy spectrum, consistent with previous studies of hypodiffusive dissipation. It is found that, across the parameter range considered, the blocking is largely insensitive to the ratio of deformation radius to the energy-containing scales.