Day–night energy exchange and its stationary-eddy mechanism. Top: cross-terminator import of MSE as a function of latitude, computed from stationary-eddy fluxes of ﹩u\,{m}^{{\prime} }﹩ and averaged in ±90° longitude bands centered at the west and east terminators (longitudes 90° and 270°). The legend lists the global nightside power P_night. Bottom: vertically integrated meridional stationary-eddy MSE transport, c_p[v*T*] + L_v[v*q*]. Both Steep and Plateau topographies enhance cross-terminator MSE import at mid-latitudes relative to Baseline, with Steep producing a sharper peak and Plateau a broader enhancement.