  We inquire about the properties of 2d Navier-Stokes turbulence simultaneously
forced at small and large scales. The background motivation comes by
observational results on atmospheric turbulence. We show that the velocity
field is amenable to the sum of two auxiliary velocity fields forced at large
and small scale and exhibiting a direct-enstrophy and an inverse-energy
cascade, respectively. Remarkably, the two auxiliary fields reconcile universal
properties of fluxes with positive statistical correlation in the inertial
range.

Fluid Dynamics;Atmospheric and Oceanic Physics