Left-hand member of Eq. (78) as function of normalised temperature difference in logarithm scale for L_sen, L_adv = 0.01, 1, 100. The functionis denoted by f. The parameters L_sen and L_adv are thenon-dimensional control parameters of sensible heating and advected heat transport defined by Eqs. (63) and (75), respectively. Parameters values: β_{L 0} = β_S0 = 1, τ_s;L = 10; τ_s;S = 0.1; F_⋆ = 1366 W m⁻²; A_s = 0.2.