Model:Lake-Permafrost with Subsidence

Lake-Permafrost with Subsidence

Also known as
Model type	Single
Model part of larger framework
Note on status model
Date note status model

Spatial dimensions	1D
Spatial extent
Model domain	Terrestrial
One-line model description	1-D lake-permafrost thermal model with subsidence.
Extended model 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.

Keywords:	thermal model, permafrost, ,

Name	Nora Matell
Type of contact	Model developer
Institute / Organization	INSTAAR, University of Colorado
Postal address 1	450 UCB
Postal address 2
Town / City	Boulder
Postal code	80305
State	Colorado
Country	United States
Email address	nlmatell@gmail.com
Phone
Fax

Supported platforms	Windows
Other platform
Programming language	Matlab
Other program language
Code optimized	Single Processor
Multiple processors implemented
Nr of distributed processors
Nr of shared processors
Start year development	2008
Does model development still take place?	No
If above answer is no, provide end year model development	2009
Code development status
When did you indicate the 'code development status'?
Model availability	As code
Source code availability (Or provide future intension)
Source web address
Source csdms web address
Program license type	GPL v2
Program license type other
Memory requirements	--
Typical run time	--

Describe input parameters	Daily average solar radiation for location (at surface).
Input format
Other input format	Matlab .mat file
Describe output parameters	Matlab variables, Matlab graphs
Output format
Other output format	Matlab variables, Matlab graphs
Pre-processing software needed?	No
Describe pre-processing software
Post-processing software needed?	No
Describe post-processing software
Visualization software needed?	No
If above answer is yes
Other visualization software

Describe processes represented by the model	Heat conduction in permafrost, lake ice growth-decay, permafrost subsidence due to excess ice
Describe key physical parameters and equations	Heat conduction equations, lake ice growth-decay equations
Describe length scale and resolution constraints	Near surface, length scale should be 5-10 cm if subsidence occurring. Deeper in permafrost, 1+ m okay.
Describe time scale and resolution constraints	Model needs daily (or smaller) timesteps.
Describe any numerical limitations and issues	Runs slowly - iterates implicit scheme. Some sort of matrix algebra might improve speed.

Describe available calibration data sets
Upload calibration data sets if available:
Describe 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).
Upload test data sets if available:
Describe ideal data for testing	Lake temperature time series, known lake depth, underlying permafrost time series. Surface temperature time series as input (not air temperature).

Do you have current or future plans for collaborating with other researchers?	--

Is there a manual available?	No
Upload manual if available:
Model website if any
Model forum / discussion board

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Authors

Nora Matell

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