Left: vertical cross-correlation for B = (1, 0, 10) (left panel) and the horizontal cross-correlations for B = (0, 1, 10) (right panel). We note that is much smaller than (see Eq. (28)). Each blue line represents the horizontal average over one snapshot. The red lines represent averages over the snapshots, and the yellow lines indicate the standard deviation. The convectively unstable part of the box is grey-shaded. The numbers in ⟨⟩-brackets are the averages taken over the whole unstably stratified layer and over time; Ω = 0, Pr = 0.1, and Pm = 0.1.