Fig. 2

Meridional profiles of the zonal component of phase-averaged energy flux associated with equatorial waves; the solid black line is \((\partial \omega /\partial k)(\overline {u^{2}+v^{2}+p^{2}})/2\), the dashed green line is \(\overline {u p}\), the dashed orange line is \(\overline {up}+(\overline {p \varphi ^{\text {app}}}/2 + \overline {u_{tt} \varphi ^{\text {app}}})_{y}\), the solid blue line is \(\overline {up}+(\overline {p\varphi ^{\text {app}}}/2)_{y}\), and the purple dots are \((\omega /k)(\overline {E-v^{2}})=(\omega /k)(\overline {u^{2}-v^{2}+p^{2}})/2\). All panels are for low-frequency equatorial waves with ω<1: a westward propagating RGWs, b short and c long RWs in the 1st meridional mode, and d short and e long RWs in the 2nd meridional mode. The associated values of meridional-mode number n, zonal wavenumber k, wave frequency ω, and group velocity ∂ ω/∂ k are noted in each panel. For each of a–e, the wave amplitude in (11a) has been set to normalize the meridional integral of wave energy: \(\int ^{\infty }_{-\infty } (\overline {u^{2}+v^{2}+p^{2}})/2 dy = 1\)