GIPL Model outputs - linear coupled – Annual

This set of files includes annual and monthly model outputs from GIPL2, a landscape scale permafrost model. The Geophysical Institute Permafrost Lab (GIPL) spatially distributed permafrost dynamics model is a transient model, which simulates soil temperature dynamics and the depth of seasonal freezing and thawing by solving non-linear heat equation with phase change numerically. The GIPL2 model captures physical processes essential to robust and appropriate modeling of soil temperature dynamics and active layer thickness. In this model, the process of soil freezing/thawing is occurring in accordance with the unfrozen water content parameterization and soil thermal properties, which are specific for each soil layer and for each geographical location. Thermal conductivity depends on soil moisture and unfrozen water content. The GIPL2 includes thermal insulation of the snow cover, and geothermal heating at the appropriately selected depth. 

These specific outputs are from the Integrated Ecosystem Model (IEM) project and are from the linear coupled version, 1901-2100. The input data for GIPL2 model are annual and monthly variables from TEM output. 
Variables on annual base.
Thickness of moss layer, [m] - moss; 
Thickness of upper organic layer (fibrous), [m] - shwldz;
Thickness of deep organic layer (amorphous), [m] - deepdz;
Constants.
Thickness of upper mineral soil layer, 0.25 m - minetopdz;
Thickness of deep mineral soil layer, 4.75 m - minebotdz;

Monthly changing variables.
Snow depth, [m] - snowdepth;
Thermal conductivity of upper organic layer (fibrous), [W/m2*K] - tcshlw;
Thermal conductivity of deep organic layer (amorphous), [W/m2*K] - tcdeep;
Thermal conductivity of upper mineral soil layer, [W/m2*K] - tcminetop;
Thermal conductivity of deep mineral soil layer, [W/m2*K] - tcminebot;
Volumetric water content of upper organic layer (fibrous), [m3/m3] - vwcshlw;
Volumetric water content of deep organic layer (amorphous), [m3/m3] - vwcdeep;
Volumetric water content of upper mineral soil layer, [m3/m3] - vwcminetop;
Volumetric water content of deep mineral soil layer, [m3/m3] - vwcminedeep;

The IEM Generation 1 is driven by outputs from historical CRU TS 3.1 data (1900-2009) and 2 AR4/CMIP3 climate model projections (2010-2100), and one projected emission scenario. The projected models include: cccma_cgcm3_1 and mpi_echam5, under the A1B emission scenario.

These outputs used TEM outputs for subsurface parameterization for 1901-2009.

Variables include:
alt: annual maximum active layer thickness or table of permafrost, [meters].
pfBase: annual minimum depth of permafrost base (permafrost thickness), [meters]
magt and mmgt: mean annual or monthly ground temperature at the surface and depths of 0.1, 0.2, 0.5, 1, 2, 3, and 5 meters [Celsius]

COMMENT: Active layer thickness (ALT) or table of permafrost. It is necessary to distinguish ALT and table of permafrost. The ALT is a thickness of the layer of ground subject to annual thawing and freezing in areas underlain by permafrost. If ALT greater than approximately 3 m it supposed to be a depth of permafrost table. At major locations of Alaska there are no freeze up at all if permafrost table getting deeper than 3 m (except of mountain areas with bare ground composed by bedrock, coarse debris and blocky materials). In this case, the residual thaw layer (talik) is exist between the seasonally frozen ground and the permafrost table. This layer may result from thawing of the permafrost, which causes a lowering of the permafrost table, or from incomplete freezing of the active layer during a mild winter after a very warm summer, or during a winter in which an unusually heavy snowfall (providing a thick insulating cover on the ground surface) occurs before extreme cold sets in. It may exist for one year or for several years, or it may be permanent if permafrost is degrading due to climatic warming, changes in terrain conditions resulting from natural (wildfire, thaw slump etc.), human disturbance or activity. This layer does not exist where the seasonal frost extends to the permafrost table.
Reference: Linell and Kaplar, 1966. 

Snow data uncertainties. Long-term three-dimensional simulations with general circulation models (GCMs) show that the Snow cover fraction (SCF) and snow depth (SD) greatly affects the climate in the Northern Hemisphere as well as subsurface thermal conditions. By means of both ground observations and remotely sensed data, several deficiencies in the SCF and SD simulated by the current GCMs were identified: over mountainous areas, a substantial overestimation in the SCF and SD was found whereas flat areas showed a distinctly underestimated SCF and SD. The comparison between remotely sensed and simulated mean monthly data revealed a significant overestimation of snow parameters in snow-covered mountainous areas (Roesch A. et al., 2001). Because snow is a strong insulator, bias in the snow thermal properties, which depend on snow depth, can strongly affect modeled soil temperature. In some cases, snow cover is a decisive factor of presence or absence of permafrost. 
Reference: Roesch, A., Wild, M., Gilgen, H. et al. A new snow cover fraction parametrization for the ECHAM4 GCM, Climate Dynamics (2001) 17: 933. https://doi.org/10.1007/s003820100153