Glacier surface temperatures in the Canadian High Arctic, 2000-15

摘要

Canada's Queen Elizabeth Islands (QEI) contain similar to 14% of the world's glacier and ice-cap area. Sparse in-situ measurements indicate that interannual variability in glacier surface mass balance in this region is driven primarily by variations in summer melt, and that the annual surface mass balance of four index glaciers has become increasingly negative since 2007. Here, we use a 16-a record of satellite-derived mean summer (June-August) land surface temperatures (LST) from NASA's Moderate Resolution Imaging Spectroradiometer to investigate large-scale spatial and temporal variability in the duration and intensity of summer melt across glaciated surfaces in the QEI from 2000 to 2015. During this period, QEI mean summer glacier surface temperatures increased at an average rate of 0.06 +/- 0.04 degrees C a(-1), for a total of nearly 1 degrees C. Most of this increase occurred between 2005 and 2012, when mean summer near-surface (2 m) and upper-air (700 hPa) temperatures were 1.0-1.2 degrees C higher than the 1948-2015 mean. There is a strong correlation between the glacier LST and 700 hPa air temperature records (r > 0.8). The period 2005-12, when mean summer LSTs were anomalously high, was likely the warmest period in the region since at least 1948.