Panels A and D: left- and right-hand sides of the MFB equation for the HD simulation. The terms were computed for the NH only, and with color saturation at ± 3 × 10⁷ s^-1. The vertical dotted line represents the TC. In the other four panels we present the individual contributions on the right-hand side: B) stretching, C) advection, E) compressibility and F) baroclinicity (with color saturation at ± 2 × 10^-7 s^-1).