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

Abstract

ABSTRACT. Canada's Queen Elizabeth Islands (QEI) contain ∼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°C a

Characterization of Canadian High Arctic glacier surface albedo from MODIS C6 data, 2001–2016

“…In 2003, negative BSA anomalies dominate the south and east of the QEI while BSA anomalies were positive in the northwest of Ellesmere Island and generally negative on Axel Heiberg Island (western QEI). This southeast-northwest spatial pattern is similar to the pattern of LST change described by Mortimer et al (2016) where LST change was greatest in the north and west of the QEI. 250…”

“…1), Arctic Canada, in 2000 was ~104,000 km 2 20 (Arendt et al, 2013). From 2000 to 2015, the summer mean surface temperature of glaciers in this region increased at a rate of 0.06 ± 0.04°C yr -1 , and summer mean air temperatures from 2005-2012 were > 1.0°C warmer than the 1948-2015 mean (Mortimer et al, 2016). QEI summer mean air and glacier surface temperatures are strongly correlated with the annual and summer glacier mass balances, which have become increasingly negative since at least 2003 (Gardner et al, 2013;Lenaerts et al, 2013;Wolken et al, 2016).…”

“…The Eight-Day L3 Global Land Surface Temperature and Emissivity product (MOD11A2) C5, which has been found to be a reasonable proxy for the duration and/or intensity of summer melting in the QEI (Sharp et al, 2011;Mortimer et al, 2016), was used to investigate the relationship between surface temperature and albedo. MOD11A2 daytime and night-time LSTs 145 are computed from MODIS channels 31 (11 µm) and 32 (12 µm) using a split-window technique and all available daytime clear-sky scenes from the Terra satellite for sequential eight day periods (Wan et al, 2002).…”

“…Pixels for which the average LST error (QC_Day LST error flag) exceeded 2°C were removed from the analysis and any remaining pixels having a temperature >0°C were assigned a temperature of 150 0°C (e.g. Hall et al, 2008a;Mortimer et al, 2016). Uncertainties in the MOD11A2 LSTs arise mainly from cloud contamination (Box et al, 2012;Hall et al, 2012) and the removal of observations when clouds are detected (Ackerman et al, 1998;Hall et al, 2008a).…”

“…Uncertainties in the MOD11A2 LSTs arise mainly from cloud contamination (Box et al, 2012;Hall et al, 2012) and the removal of observations when clouds are detected (Ackerman et al, 1998;Hall et al, 2008a). Variability in the number of clear-sky days within each observation period and from one year to the next was not found to introduce significant variability in the MODIS-derived LST relative to the true surface temperature in the QEI (see Mortimer et al, 2016). MOD11A2 data were downloaded from (https://lpdaac.usgs.gov/, accessed 155 …”