Sublimation's impact on temporal change of albedo dichotomy on Iapetus

► We model the temporal change of surface albedo due to the effect of ice sublimation. ► Icy sublimation produces greatly difference from the initial albedo state. ► Current albedo distribution can be reconstructed from the sinusoidal distribution. ► It suggests the external origin of the albedo dichotomy. ► The depth of the layer where the dark materials exist should be an order of 10 cm.