An inventory and topographic analysis of glaciers in the Torngat Mountains, northern Labrador, Canada

Abstract

ABSTRACT. This study presents the first complete glacier inventory of the Torngat Mountains, northern Labrador, Canada. In total, 195 glaciers and ice masses are identified, covering a total area of 24.5 � 1.8 km 2 . Mapped ice masses range in size from 0.01 to 1.26 km 2 , with a median size of 0.08 km 2 . Ice masses have a median elevation of 776 m a.s.l. and span an altitudinal range of 290-1500 m a.s.l. Indications of ice flow suggest at least 105 active glaciers in the Torngat Mountains. Analysis of morphometric and topographic parameters suggests that the regional distribution of ice masses is linked to physiographic setting while the preservation of coastal ice masses at low elevation is related to local meteorological conditions. In the most coastal environments, ice masses are shown to exist below the regional glaciation level due to topographic shadowing, coastal proximity and widespread debris cover. This study provides a baseline for future change assessment.

Recent changes in area and thickness of Torngat Mountain glaciers (northern Labrador, Canada)

“…Precipitation during winter is generated by storms that are directed by the influence of the Canadian Polar Trough on the position of Arctic and polar fronts (Moore et al, 2011). Glaciers in the Torngat Mountains are preserved due to their proximity to this coastal moisture source, as well as their topographic setting (reducing incoming solar radiation receipt) and, in some cases, the insulating effect of supraglacial debris (Rogerson, 1986;Rogerson et al, 1986b;Way et al, 2014). The four glaciers measured in the early 1980s are influenced by a combination of these factors.…”

“…Finally, climate and reanalysis datasets are selected to view both 20th-century area changes and 1980s and late-2000s glacier mass balances in the context of prevailing climatic trends. This study builds on earlier work (Brown et al, 2012;Way et al, 2014;Way et al, 2015) and provides the first comprehensive, regional-scale remote-sensing and field-based assessment of the contemporary state of Labrador glaciers and their likely climate sensitivities, the results of which may be incorporated into both regional impact assessments and syntheses of global glacier mass balance.…”

“…These results were linked to annual variations in winter precipitation (Rogerson, 1986). Aside from the 2005 inventory (Way et al, 2014), no more recent information is available regarding the health of these four glaciers or of the remaining glacial ice in Labrador. A key question is the extent to which glaciologically relevant climate variables in northern Labrador have changed in concert with Arctic warming during the 20th century (Kaufman et al, 2009), and how these changes have affected Labrador glaciers.…”

“…Forbes, 1938;Henoch and Stanley, 1968), a complete inventory and analysis of the glaciers of the Torngat Mountains, covering a total active glacier area in 2005 of 22.5 ± 1.8 km 2 (not including relict ice), has only recently been completed and incorporated into global glacier datasets (Way et al, 2014;Pfeffer et al, 2014;Arendt et al, 2015). Combining the new regional glacier inventory (Way et al, 2014) with field-and remote-sensing-based analyses, Way et al (2015) showed a consistent glacial response to centennial-scale regional climate warming by documenting a 52.5 % reduction in ice extent since glaciers reached their Little Ice Age (LIA) maxima (dated to between 1581 and 1673).…”

“…The 2005-dated inventory of Way et al (2014) (derived from very high resolution aerial orthophotos) is used as a basis for historical change assessment since the mid-20th century by comparing to glacier outlines derived from archival aerial survey photography (1950). Recent glacier changes are calculated using glacier areas derived from high-resolution spaceborne electro-optical imagery (2008).…”