Mass balance of the Prince of Wales Icefield, Ellesmere Island, Nunavut, Canada

Abstract

[1] This paper estimates the mass balance of the Prince of Wales Icefield, Ellesmere Island, Canada, averaged over four decades, from measurements of surface mass balance (SMB) and iceberg calving. Shallow ice core net accumulation measurements and annual mass balance stake measurements are used in conjunction with a digital elevation model and knowledge of the location of the dominant moisture source for precipitation over the ice cap to interpolate and extrapolate spatial patterns of SMB across the Prince of Wales Icefield. The contribution of iceberg calving to the mass balance is calculated from estimates of (1) the annual volume of ice discharged at the major tidewater glacier termini and (2) the annual volume loss or gain due to terminus fluctuations. Two different approaches to determining the SMB conclude that the SMB of the ice field is approximately in balance (average equals À0.1 ± 0.4 km 3 w.e. a À1, where w.e. means water equivalent) largely because of its proximity to the main year-round moisture source that is the Smith Sound portion of the North Open Water polynya. Iceberg calving is a highly significant component of mass loss (À1.9 ± 0.2 km 3 w.e. a À1 ) and is sufficient to make the overall mass balance of the ice field averaged over the period 1963-2003 clearly negative (À2 ± 0.45 km 3 w.e. a À1 , equivalent to a mean-specific mass balance across the ice field of À0.1 m w.e. a À1). The Prince of Wales Icefield contributes $0.005 mm a À1 to global eustatic sea level rise.

Glacier velocities and dynamic ice discharge from the Queen Elizabeth Islands, Nunavut, Canada

“…This suggests a recent flow acceleration, although the moderate velocity increase and lack of other evidence (e.g., looped moraines and new crevassing) suggests that this is unlikely due to surging. The higher velocities of these four glaciers may reflect relatively high local accumulation rates due to proximity to yearround moisture sources in the North Open Water Polynya and Baffin Bay [Mair et al, 2009;Koerner, 1979]. Copland et al [2003b] determined velocities of 1000 m a À1 along the whole 25 km length of Mittie Glacier in 1999, and Short and Gray [2005] determined flow speeds of up to~1000 m a À1 at the terminus of Mittie Glacier in winter 2003 and~700 m a À1 in 2004.…”

“…Total ice discharge from QEI glaciers is currently 2.6 ± 0.8 Gt a −1 (Table S1). Ice discharge estimates reported here are similar to previous estimates from studies of selected glaciers within this region [ Van Wychen et al ., ; Short and Gray , ; Mair et al ., ; Williamson et al ., ; Burgess et al ., ]. A limited number of glaciers account for most of the ice discharge from the QEI, and ~50% of total ice flux is channeled through just the Trinity and Wykeham Glaciers that drain POW Icefield (although this value likely varies temporally due to the frequent occurrence of tidewater glacier surging, or other forms of velocity variability, in the QEI).…”

“…The Queen Elizabeth Islands (QEI; Devon, Ellesmere, and Axel Heiberg Islands; Figure 1 inset) contaiñ 104,000 km 2 of glacier ice, which represents 25% of Arctic glacier ice outside the Greenland Ice Sheet [Arendt et al, 2012]. Long-term surface mass balance records from this region indicate that prior to the late 1980s the ice masses were largely in balance [Koerner, 2005;Mair et al, 2009;Sharp et al, 2011]. Since the late 1980s, however, and especially since 2005, changing summer atmospheric circulation patterns have increased advection of warm air from the northwest Atlantic to the Canadian High Arctic, leading to increased surface melt, longer melt seasons, and increased anticyclonic air circulation over the QEI in summer [Gardner et al, 2011;Sharp et al, 2011;Lenaerts et al, 2013].…”

Characterizing interannual variability of glacier dynamics and dynamic discharge (1999–2015) for the ice masses of Ellesmere and Axel Heiberg Islands, Nunavut, Canada

“…This thinning is similar to the rate of ~3.5 m a −1 determined from a comparison of repeat ICESat surface elevation profiles acquired between 2003 and 2009 [ Gardner et al ., ]. In comparison, surface elevation changes of two glaciers located within ~8 km and ~15 km of the Trinity/Wykeham calving front (also derived from the 2008 SPOT DEM and the 2014 NASA ATM data) averaged ~−0.61 m a −1 , while mass balance measurements and modeling suggest that surface ablation via melting in this area is < 2 m a −1 [ Mair et al ., ; Marshall et al ., ]. This implies that at least half of the observed thinning rate of the terminus of Trinity Glacier is attributable to changes in dynamics.…”

Glacier change from the early Little Ice Age to 2005 in the Torngat Mountains, northern Labrador, Canada

“…While historical glacier changes for the large glacier populations of the Canadian Arctic are comparatively well studied (e.g., AMAP, 2011;Dowdeswell et al, 2007;Mair et al, 2009;Paul and Svoboda, 2009;Sharp et al, 2014;Svoboda and Paul, 2009;Way, 2015), the lowArctic glaciers in the Torngat Mountains of northern Labrador have yet to be assessed for historical change on a regional scale . Several local studies conducted south of Nachvak Fiord (Fig.…”