Earth-based observations of Martian albedo changes

The large-scale albedo features of Mars, as observed with Earth-based telescopes, undergo secular changes, cyclic seasonal changes, seemingly random day-to-day changes, and cyclic diurnal changes. The suspension or redistribution of dust may be involved in all four. Some of the recent findings, based on extensive new Earth-based data, are at variance with classical ideas. Current methods of observation and analysis need to be pursued until all Martian seasons have been equally sampled.