SPATIAL AND TEMPORAL GRADIENTS OF SNOW ISOTOPES AND ISOTOPE-TEMPERATURE RELATIONSHIPS ON THE PRINCE OF WALES ICEFIELD, ELLESMERE ISLAND, NUNAVUT

Air temperature measurements and snowpit isotope stratigraphies were collected from 2001 to 2003 at 25 sites on the Prince of Wales (POW) Icefield, Ellesmere Island, Nunavut. The study sites span an area of 15,500 km2 and range from an altitude of 130 m to 2010 m on the summit of the Icefield. The POW Icefield receives most of its moisture from the southeast (Baffin Bay and the Labrador Sea), as reflected by the strong east-west assymetry in snow accumulation rates on the Icefield; as a result, glaciers on the east coast extend to sea level, while the outlet glaciers on the western margin terminate terrestrially at elevations of 400-600 m. Consistent with this prevailing pattern of precipitation over the Icefield, heavy snow-water isotopes (oxygen-18 and deuterium) become progressively depleted as a function of distance from the east coast. This effect is equal to air temperature in its importance in determining the spatial pattern of snow-water isotopes over the Icefield. In contrast, temporal variability of O18, deuterium, and deuterium excess in multiyear snowpits and shallow ice cores from the summit site bear a better relationship with seasonal and interannual temperature variability. We compare the spatial and temporal gradients of the observed O18-temperature relationship and comment on the implications for isotope-temperature thermometry in a deep ice core being collected from the summit site in spring 2005.