Energy balance and ground thermal regime studies broughton Island, Northwest Territories, Canada

Abstract

This paper examines the relationship between energy balance and ground thermal regime over a variety of tundra surfaces in a low arctic environment. The Bowen ratio and energy balance data emphasized the dominance of latent heat fluxes over the freely evaporating terrain. The sensible heat flux was negative, owing to persistent surface inversions, and supplied energy for evaporation. The ground heat flux was minimal until July 6 and the major increase on that date resulted in a sharp rise in the rate of ground thawing. The deepest measured penetration (80 cm) was achieved in moist sandy soil, compared with 50 cm depth in adjacent clay loam, despite the similarity between Bowen ratios at both sites. Energy balance data do not account for active layer variations and independent soil factors appear to exert the major control on ground ice melt. The paper concludes with a discussion of Bowen ratios and energy balance at the study area vis-a-vis other snowfree tundra environments.