Figure 1.

(a) Diurnal cycle of the incoming solar radiation at the equator during the equinox (λ = 0, NH vernal equinox, green) and solstice (λ = π/2, NH summer solstice, red), and at 89^∘S during the solstice (λ = 3π/2, NH winter solstice, blue). (b) Diurnal cycle of the surface temperature at the equator during the equinox (λ = 0, NH vernal equinox, green) and the solstice (λ = π/2, NH summer solstice, red). The dotted and dashed horizontal lines indicate the daily mean surface temperature calculated using the depth-dependent model [Eq. (29)] (dotted) and the daily mean radiation [Eq. (32)] (dashed). (c) The temperature versus depth at the equator at the equinox (λ = 0, NH vernal equinox) at several times during the diurnal cycle. Note the fast decline in temperature oscillations with depth. (d) Same as b but for 89^∘S, at the solstice (λ = 3π/2, NH winter solstice). The temperature was obtained by integrating the depth-dependent model [Eq. (29)] at a specific latitude.