Near-Surface Soil Heat and Water Fluxes in Different Permafrost Terrains, Churchill, Manitoba

Abstract

<p>Soil temperatures and active layer depths were recorded near Churchill, Manitoba to determine the near-surface thermal regime for three different permafrost terrains. Soil moisture and net radiation were measured also. The interaction between the heat and water balance of the active layer was investigated to observe the short term effects of water movement on active layer development. Results show that the soil heat component of the surface energy budget composed 18% of the net radiation in the grassland, 14% in the peat and 13% in the tundra. In all terrains at least 93% of the soil heat is consumed in latent heat of fusion. Evaluation of the water budget indicates a large subsurface water loss from the upland tundra and a moderate gain in the grass lowlands during the summer period. Active layer development is shown to respond to both the conductive heat flux and the thermal exports and imports associated with the subsurface water flux.</p>