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Abstract:
Modeling soil thermal dynamics at high latitudes
and altitudes requires representations of physical processes
such as snow insulation, soil freezing and thawing and subsurface
conditions like soil water/ice content and soil texture.
We have compared six different land models: JSBACH, ORCHIDEE,
JULES, COUP, HYBRID8 and LPJ-GUESS, at
four different sites with distinct cold region landscape types,
to identify the importance of physical processes in capturing
observed temperature dynamics in soils. The sites include
alpine, high Arctic, wet polygonal tundra and non-permafrost
Arctic, thus showing how a range of models can represent
distinct soil temperature regimes. For all sites, snow insulation
is of major importance for estimating topsoil conditions.
However, soil physics is essential for the subsoil temperature
dynamics and thus the active layer thicknesses. This analysis
shows that land models need more realistic surface processes,
such as detailed snow dynamics and moss cover with changing thickness and wetness, along with better representations of subsoil thermal dynamics.
