STUDY AREA AND DATA SOURCES
The study area is Reynolds Mountain in the Owyhee Mountains in Idaho,
USA. Reynolds Mountain is a zero-order basin that drains to the Snake
River (Figure 1). Reynolds Mountain has a small drainage area (0.38
km2) and it is characterized by large patches of steep
north and west facing slopes (Figure 2c). Elevation ranges in Reynolds
Mountain vary between 2028 m and 2137 m. The vegetation is dominated by
low, big, and Wyoming sagebrush (Artemisia arbuscula Nutt.,
Artemisia tridentata Nutt. subsp. vaseyana [Rydb.] Beetle and
subsp. Wyomingensis, respectively), bitterbrush (Purshia
tridentata [Pursh] DC), and native and non-native grasses,
including cheatgrass (Bromus tectorum ). Aspen (Populus
tremuloides ), subalpine fir (Abies lasiocarpa ), and Douglas-fir
(Pseudotsuga menziesii ) communities are found in the water-rich
areas such as below drifts and riparian zones. Figure 3 shows a
distribution of the sagebrush and forest communities. Soils in Reynolds
Mountain are derived from igneous granitic and volcanic rocks and lake
sediments.
Reynolds Mountain has been monitored since 1983. The instrumentation
includes a streamflow gauge at the basin outlet and two sheltered and
exposed weather stations (Figure 1). The meteorological data include
hourly air temperature, relative humidity, wind speed, precipitation
(snow undercatch-corrected), shortwave radiation, and longwave
radiation, which are used to force the hydrological model. The
hydrological data include hourly snow water equivalent (SWE)
measurements at a snow pillow site and hourly streamflow observations at
the basin outlet. A snow pillow was used near the sheltered station to
estimate SWE. Reba et al. (2011b) suggest that the snow accumulation at
this site is enhanced by the impact of topographic and vegetation
sheltering on wind redistribution. On the contrary, Winstral and Marks
(2014) showed that SWE measurements at the snow pillow site are
representative of the basin averages. The snow pillow SWE measurements
and a lidar-derived snow depth product were used in this study for
assessing the model performance in capturing the spatial variability of
snow accumulation (Shrestha & Glenn, 2016). Lidar-derived snow depths
were obtained from processing and then subtracting a snow-free lidar
digital elevation model (DEM) from a snow covered DEM in Reynolds
Mountain on March 19, 2009.