Warmer–wetter climate drives shift in δ D –δ 18 O composition of precipitation across the Queen Elizabeth Islands, Arctic Canada

• Published in: Arctic Science
• Main Authors: Copland, Luke, Lacelle, Denis, Fisher, David, Delaney, Frances, Thomson, Laura, Main, Brittany, Burgess, David
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2021
• Subjects: General Earth and Planetary Sciences; General Agricultural and Biological Sciences; General Environmental Science; Arctic; Canada; Agassiz Ice Cap; White Glacier; glacier*; Ice cap; Queen Elizabeth Islands; Sea ice
• Online Access: http://dx.doi.org/10.1139/as-2020-0009; https://cdnsciencepub.com/doi/full-xml/10.1139/as-2020-0009; https://cdnsciencepub.com/doi/pdf/10.1139/as-2020-0009

We examine how recent increases in air temperature and precipitation, together with reductions in sea ice extent, may have affected the regional δD–δ 18 O composition of precipitation. In spring 2014, 80 snow samples were collected from six glaciers and ice caps across the Queen Elizabeth Islands, and in 2009 and 2014, two shallow ice cores were collected from Agassiz Ice Cap and White Glacier, respectively. The snow samples showed average δ 18 O values from 2013 to 2014 to be approximately 2‰–3‰ higher than those recorded in 1973–1974 in nearby locations, with the ice cores showing similar trends in δ 18 O values. A zonal average water isotope model was used to help understand the causes of the increased δ 18 O values, using inputs calibrated for observed changes in temperature, vapour flux, and sea ice extent. Model results indicate that atmospheric temperature changes account for <1‰ of the observed change in δ 18 O values, and that changes in local water input and precipitation driven by changes in sea ice extent only have an effect in coastal regions. Enhanced meridional vapour flux to the Queen Elizabeth Islands is, therefore, also required to explain the observed increases in δ 18 O values, with fluxes ∼7% higher today than in the 1970s, consistent with the change in precipitation.