Time series of enhanced resolution QuikSCAT scatterometer images were used to map the extent and duration of surface melt and the distribution of ice layer formation on the Greenland ice sheet in the period 2000-2004. Apart from the bare ice and the mixed pixels (10%) along the ice sheet margin where melt cannot be determined reliably, annual melt duration and melt anomaly maps were produced across the ice sheet (90%) for each summer. Over the 5-year period, the mean melt duration for the ice sheet ranged from 14.3 to 20.5 days. The proportion of the ice sheet that experienced melting in a given year ranged from 44.2% to 79.2%. Extensive melt in 2002 was caused by a single melt event of a few days duration. This event was associated with the intrusion of a ridge of high pressure from the North Atlantic Ocean that brought warm air onto the ice sheet. The change in biweekly averaged backscatter between the freeze-up periods in the current and previous falls was used to identify changes in the distribution of ice layers in snow between successive melt seasons. 2002 had the maximum melt extent and duration, and ice layer formation extended to higher elevations than in other years. Inter-annual changes in the distribution of ice layer formation may be associated with changes in surface height that are not necessarily indicative of mass balance changes. Mapping of ice layer formation is thus potentially useful for interpreting both real and apparent height changes measured by altimetry.