Accumulation, Ablation, and Oxygen Isotope Variations on the Queen Elizabeth Islands Ice Caps, Canada

Measurements made on traverses over ice caps in the Queen Elizabeth Islands show that there is a region of very high accumulation (>40 g cm –2 year –1 ) on the slopes facing Baffin Bay and one of low accumulation (<15 g cm –2 year –1 ) in the interior parts of northern Ellesmere Island. Ablation rates in summer show much less regional variation over the same ice caps except for lower rates along the north-west edge of the islands and possibly on the Baffin Bay slopes as well. However, there is a stronger relationship between ablation and elevation which is exponential below the firn line. From the fractional 18 O content of the snow it is shown that Baffin Bay contributes significant amounts of moisture (>20% of the total) to the Baffin Bay slopes. In addition the Arctic Ocean is seen as another, but much less significant, moisture source. The δ 18 O data show two effects on the condensation processes—an orographic one (i.e. adiabatic cooling) and a distance-from-source effect (isobaric cooling) where the source is somewhere to the south-east of the islands.