Surface Energy Exchange over an Arctic Snowpack:
Comparison of Two Snow Models
H. Koivusalo1 and M. Heikinheimo2
The objective was to simulate energy exchange, skin temperature, and albedo at the snow surface
using standard meteorological data. Snow and micrometeorological measurements were taken at
a site located 100 km north of the Arctic Circle in Finland. The site was an opening within a
sparse coniferous stand. Point measurements of vertical snow temperature and density profiles,
snow surface skin temperature, net radiation, and albedo had been taken during MarchMay
1997. Standard three-hour meteorological measurements were available near the snow site at the
Sodankyla Meteorological Observatory. The study period included two weeks of measurements
of turbulent heat fluxes with the eddy correlation method above snow as a part of the NOPEX-
WINTEX project, "Land-surface-atmosphere interactions in a wintertime boreal landscape." Two
joint models with different snow process representations were tested to assess the necessary level
of complexity to compute radiative and turbulent energy fluxes at the snow surface. UEB (Tar-
boton and Luce 1996) was chosen as a simple modeling approach, which derived the relevant en-
ergy fluxes at the snow/air interface but treated the snowpack as one layer. SNTHERM (Jordan
1991) represented a sophisticated model to simulate mass and energy transfer in detail at the
snowpack boundaries and within the snow cover. The performance of the UEB was checked
against both the measurements and the results of the SNTHERM, which was also tested using the
information on internal snow-cover properties. The measurements on the turbulent energy trans-
fer were used to check the modeled fluxes and the assumed logarithmic profile of vertical wind
distribution. The UEB showed reasonable performance for the overall mass and energy balance
during spring 1997 after the parameters of the albedo procedure were adjusted for snowmelt con-
ditions. The latent heat flux calculated by the UEB was close to the measured flux and the
SNTHERM results. The modeled sensible heat fluxes deviated slightly from each other and from
the measurements, which presumably included contribution from the coniferous stand acting as
an additional heat sink/source.
1
University of Technology, P.O. Box 5200, FIN-02015 HUT, Finland
2
Finnish Meteorological Institute, P.O. Box 503, FIN-00101 Helsinki, Finland
7
Previous Page
