Predicted poleward decrease in deep layer density (top; blue line) and increase in transition width (bottom; orange line) based on the minimization of the latitudinal gradient for the Diviner regolith temperatures. Illustrated together with the poleward decrease in diurnal temperature amplitude in depths of 1 cm (dashed), 5 cm (dash-dotted), and 10 cm (dotted). The y axis of the diurnal temperature amplitudes is set to match the start and end values of the deep layer density or transition width variation.