Why have we expanded BEPS to landscape level?
The original Boreal Ecosystem Productivity Simulator (BEPS)
was designed for remote sensing measurements at the scale
of 1 km2 or better spatially and day to month
temporally. Outputs of BEPS cover areas of more than 104 km2.
No detailed topographic characteristics are included. An integration
of BEPS with topographic and local hydrological attributes
is a necessary step in validating nation-wide NPP and NEP
maps using high resolution images in selected areas.
Which sites are selected for testing?
Three study sites have been selected.
- Site A is located in typical boreal forest areas
in central Saskatchewan, Canada. This site is also part
of the BOREAS Southern Study Area and numerous data sets
are therefore available. Typical of boreal forests, this
site is generally flat with slightly undulating terrain
modified during the last glacial period. From drier upland
to wet lowland, jack pine, aspen and black spruce stands
and their mixes are the dominant vegetation.
- Site B is situated in central Quebec. This site
is near the southern boundary of boreal forests where sugar
maple and balsam fir stands dominate. Abundant rainfall
(>1000m) and medium relief are the main features of this
site. Some baseline data of this site have been collected
by the Canadian Forest Service, and parts of the watersheds
have been gauged.
- Site C is proposed for the east slope of the Rocky
Mountains in the Kananaskis area of Alberta, Canada. Local
relief in this area can rise to 2000 m. Most of the Lodgepole
pine and mixed stands are distributed at middle-to-bottom
positions on the slopes. High soil permeability and low
rainfall contrast with the other sites.
These three sites are representative of typical Canadian inland
forest areas.
How will we run BEPS at landscape level?
Within each site, Digital Elevation Models (DEMs) will be
used to derive more site-explicit data such as slope magnitude
and aspect, drainage network, flow direction, flow accumulation
and watershed boundary layers. In addition to the climatic
data and to Leaf Area Index (LAI) information derived from
remotely sensed data, NPP will be calculated at a more detailed
scale (as detailed as individual pixels, 30m by 30m). At the
landscape level, direct canopy radiation will be calculated
by taking topography into account. Initial parameters to calculate
the radiation are time of day, day of year, site location
(longitude and latitude), slope, and aspect. Soil moisture
balance will be calculated for each pixel with consideration
of surface flow, subsurface flow, and flow accumulation as
well as rainfall interception and evapotranspiration. Generic,
physically based hydrological models such as Regional HydroEcological
Simulation System (RHESSys) (Band, et al., 1993) and CASC2D
(Julien and Saghafian, 1991) are being considered.
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