Mass balance of Devon Ice Cap, Canadian Arctic

Interferometric synthetic aperture radar data show that Devon Ice Cap (DIC), northern Canada, is drained through a network of 11 glacier systems. More than half of all ice discharge is through broad flows that converge to the southeast of the ice cap, and these are grounded well below sea level at their termini. A calculation of the ice-cap mass budget reveals that the northwestern sector of DIC is gaining mass and that all other sectors are losing mass. We estimate that a 12 489 km(2) section of the main ice cap receives 3.46 +/- 0.65 Gt of snowfall each year, and loses 3.11 +/- 0.21 Gt of water through runoff, and 1.43 +/- 0.03 Gt of ice through glacier discharge. Altogether, the net mass balance of DIC is -1.08 +/- 0.67 Gt a(-1). This loss corresponds to a 0.003 mm a(-1) contribution to global sea levels, and is about half the magnitude of earlier estimates.