The net heat loss resulted in a 6.3 ☌ cooling of the average soil surface temperature and caused the active layer thickness to decrease by nearly 2 m, thus stopping permafrost warming, promoting permafrost recovery and its upward aggradation in the embankment. The design of the ACRS blocked incoming solar radiation, prevented snow accumulation, and promoted air convection through the stack effect, which resulted in a cooling efficiency of 358% compared with the reference site. Soil surface, air, and ground temperatures were recorded under the ACRS between 20, and were then compared with values from an unmitigated road embankment and from the natural ground near the road embankment. The results show that both the amount of subglacial discharge and submarine melting meltwater are correlated to the amount of positive degree days (PDD).Ībstract: This study tested the efficacy of air-convection-reflective sheds (ACRS) installed along the Alaska Highway in Yukon (Canada) as a mitigation technique to reduce heat absorption during the thawing season and to increase heat loss during the freezing season. We subsequently use eight years of water profiles taken in Milne Fiord, Nunavut (80.6°N, 82.5°W) to demonstrate the technique and investigate subglacial discharge and submarine melting in this fjord. Our results show that the standard method for comparing to ambient profiles may underestimate the amount of meltwater by up to 30%. Here, we develop a technique to depth-correct the ambient profiles to account for buoyancy difference following mixing with meltwater. This is typically done by comparing a temperature–conductivity–depth (CTD) profile close to the glacier with one that represents ambient oceanographic conditions farther offshore. Quantifying subglacial discharge and submarine melting is critical to understanding fjord oceanography and cryospheric change in the catchment. The release of water produced by glacial meltwater runoff that finds its way to the bottom of the glacier is known as subglacial discharge, whereas submarine melting is the direct melting of the glacier by the ocean water. Two main oceanographic processes occur at the termini of tidewater glaciers during summer. However, in the Canadian High Arctic, the role of fjords is not well understood, in part because of the lack of oceanic measurements. Abstract: There has been a recent focus on Greenlandic fjord oceanography as half of this island’s contribution to sea level rise comes from submarine melting and ice discharge at tidewater glaciers.
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