Snowmelt and soil thaw energy in sub-alpine tundra, Wolf Creek, Yukon Territory, Canada

To accurately represent subsurface flow in a hydrologic model of permafrost terrain during spring thaw, an understanding of soil thaw and soil thaw rates is required. Research was conducted on an organic-covered hillslope in Granger Basin, Yukon Territory, to quantify relationships between net radiation, snowmelt and soil thaw energy. The infiltration and freezing of meltwater into the soil may contribute to pre-thaw warming. When this energy (1.82 MJ•m-2•d-1) is taken into account, the daily mean contribution to soil thaw from net radiation is approximately 9%. Measured and estimated soil thaw depth s compared well (R2 = 0.75) when energy was distributed across the hillslope. This research contributes to the understanding of active layer development, sheds insight into the role of infiltrating and freezing meltwater on soil thaw, and provides an approach for the estimation of soil thaw based on a direct link between surface net radiation and the subsurface energy regime.