Model:Lake-Permafrost with Subsidence
From CSDMS
Lake-Permafrost with Subsidence
Introduction
History
Papers
Lake-Permafrost with Subsidence Questionnaire
Contact Information
| Model: | Lake-Permafrost with Subsidence |
| Contact person: | Nora Matell |
| Institute: | CU Boulder - INSTAAR |
| City: | Boulder |
| Country: | USA |
| Email: | nlmatell@gmail.com |
| 2nd person involved: | -- |
| 3rd person involved: | -- |
Model description
| Model type: | Single model for the terrestrial domain. |
| Description: | Models temperature of 1-D lake-permafrost system through time, given input surface temperature and solar radiation. Model is fully implicit control volume scheme, and cell size can vary with depth. Thermal conductivity and specific heat capacity are dependent on cell substrate (% soil and % ice) and temperature using the apparent heat capacity scheme where freezing/thawing occurs over a finite temperature range and constants are modified to account for latent heat. Lake freezes and thaws depending on temperature; when no ice is present lake is fully mixed and can absorb solar radiation. Upper 10 m substrate contains excess ice and, if thawed, can subside by this amount (lake then deepens by amount of subsidence). "Cell type" controls whether cell has excess ice, only pore space ice, or is lake water. |
Technical information
| Supported platforms: | Windows |
| Programming language: | Matlab |
| Model development started at: | 2008 and ended in 2009 |
| To what degree will the model become available: | Source code will be available |
| Current license type: | GPLv2 |
| Memory requirements: | -- |
| Typical run time: | -- |
Input / Output description
| Input parameters: | Daily average solar radiation for location (at surface). |
| Input format: | matlab .mat file |
| Output parameters: | Matlab variables, Matlab graphs |
| Output format: | Matlab variables, Matlab graphs |
| Post-processing software (if needed): | -- |
| Visualization software (if needed): | -- |
Process description
| Processes represented by model: | Heat conduction in permafrost, lake ice growth-decay, permafrost subsidence due to excess ice |
| Key physical parameters & equations: | Heat conduction equations, lake ice growth-decay equations |
| Length scale & resolution constraints: | Near surface, length scale should be 5-10 cm if subsidence occurring. Deeper in permafrost, 1+ m okay. |
| Time scale & resolution constraints: | Model needs daily (or smaller) timesteps. |
| Numerical limitations and issues : | Runs slowly - iterates implicit scheme. Some sort of matrix algebra might improve speed. |
Testing
| Available calibration data sets: | -- |
| Available test data sets: | Permafrost model can be tested with ground temperature time series at several depths. Lake model can be tested with known ice depths (though snow, not accounted for in model, can affect depth by several 10s of cm). |
| Ideal data for testing: | Lake temperature time series, known lake depth, underlying permafrost time series. Surface temperature time series as input (not air temperature). |
User groups
| Currently or plans for collaborating with: | -- |
Documentation
| Key papers of the model: | Model based on previous models by Ling and Zhang (2004), Plug and West (2008), Liston and Hall (1995). Model described in Matell et al. (in preparation) and Matell (2009, masters thesis). |
| Is there a manual available: | no |
| Model website if any: | -- |
Additional comments
| Comments: | -- |
