Data Sources

Three instrumented headwater research basins located in the northern North American Cordillera are used to simulate potential hydrological responses to warming and precipitation changes; Wolf Creek, Yukon Territory, Canada; Marmot Creek, Alberta, Canada; and Reynolds Mountain East (hereafter Reynolds Mountain) catchment, Idaho, USA (Figure 1). The availability of long-term data from multiple hydrometeorological stations at different elevations in each basin, makes these basins uniquely suitable case studies for conducting sensitivity analysis on hydrological processes. High quality measurements of hourly air temperature, relative humidity, wind speed, incoming shortwave radiation, precipitation, and streamflow discharge for each basin were used. Consistent with the Ideal Gas Law, relative humidity was held constant to allow water vapour pressure to change with temperature. The forcing data are publically available (Wolf Creek: Rasouli et al., 2019c; Marmot Creek: Fang et al., 2019; Reynolds Mountain: Reba et al., 2011).
All three basins are snow-dominated under the current climate and are partially covered by coniferous forest at lower altitudes: Wolf Creek has spruce and pine forests, Marmot Creek has larch, fir, spruce, and pine forests; and Reynolds Mountain has fir, pine, and aspen forests. All elevations in Wolf Creek and the high elevations in Marmot Creek are very cold. A cold snow season with high precipitation leads to a long winter at high elevations in Marmot. High wind speeds in in the alpine zones of all three basins redistribute snow by wind transport and result in blowing snow sublimation losses. Needleleaf canopy snow interception and sublimation losses are important in all three basins. Air temperatures of the forested elevations in Wolf Creek are lower than for the alpine zone in winter, due to strong inversions in the Yukon River Valley. In contrast, Reynolds Mountain and low elevations in Marmot Creek have warmer air temperatures with fewer freezing days, making these more sensitive to warming.