Zonal momentum balance components for the 10 bar simulation (colorbar is in units of 10⁻⁴ m s⁻²). (a) Coriolis acceleration $-f\overline{v}$, where f is the Coriolis parameter. (b) Eddy meridional momentum flux convergence $-{\mathrm{\partial }}_y\overline{u^{\mathrm{\prime }}{v}^{\mathrm{\prime }}}$. (c) Mean momentum flux convergence, including the mean meridional flux of relative vorticity $\overline{\zeta }\overline{v}$, where ζ is the relative vorticity, and the mean vertical momentum flux convergence $\overline{w}{\mathrm{\partial }}_{\sigma }\overline{u}$. (d) Sum of eddy flux convergence, i.e., $-{\mathrm{\partial }}_y\overline{u^{\mathrm{\prime }}{v}^{\mathrm{\prime }}}-{\mathrm{\partial }}_{\sigma }\overline{u^{\mathrm{\prime }}{w}^{\mathrm{\prime }}}$. (e) Eddy vertical momentum flux convergence $-{\mathrm{\partial }}_{\sigma }\overline{u^{\mathrm{\prime }}{w}^{\mathrm{\prime }}}$. (f) Leading order balance at 250 hPa. The vertical axis for the momentum budget terms is ±2 × 10⁻⁴ m s⁻² and for the zonal mean (black curve) ±320 m s⁻¹.