The decay kinetics of sinusoidal surface profiles on copper annealed in a hydrogen atmosphere were investigated in the temperature range 600 to 1030 "C in order to determine the temperature dependence of the surface self-diffusion coefficient, D,. Below 910 "C the surface profiles were found to be faceted resulting in an apparent discontinuity in D, which can be understood in terms of the y-plot of copper. The discontinuity in the diffusion data can be expressed by the following equations:At temperatures below 800 "C D, is dependent on the annealing time, and in the vicinity of 600 "C, D, drops drastically below the minimum value that can be measured. This behavior can be explained in terms of the rate theory for a bimolecular surface reaction between impurities and diffusing defects.