frozen_soil

Author:

Keith Cherkauer

Date:

May 18, 1996

Description:

This subroutine was created to solve a temperature profile through the soil column to determine the depth of freezing and thawing fronts, and redistribute soil moisture accordingly. Soil thermal parameters are calculated based on soil layer moisture content from the previous time step.

References

Unfrozen Soil Water Content: Flerchinger, G. N., and K. E. Saxton, "Simultaneous Heat and Water Model of a Freezing Snow-Residue-Soil System: I. Theory and Development," Transactions of the ASCE, Vol. 32(2), March-April, 1989. pp 565=571

Input Variables:

Variable	Type	Units	Description
soil_con	soil_con_struct	N/A	Soil parameter structure uses: depth - depth of std layers soil_density - soil partical density bulk_density - soil bulk density max_moist - maximum layer moisture bubble - bubbling pressure expt - exponential
layer	layer_data_struct *	N/A	Soil Layer Data Structure uses: moist_thaw - thawed soil sublayer moisture moist_froz - frozen soil sublayer moisture moist - unfrozen soil sublayer moisture ice - soil layer ice content
energy	energy_bal_struct *	N/A	Energy Balance Structure uses: dz - profile layer thickness fdepth - freezing and thawing front depths T - temperature profile ice - layer ice content
rec	int	N/A	Current record number
veg	int	N/A	Current vegetation type
dt	int	hr	Model time step
surf_temp	double *	C	Soil surface temperature
N_Ts	int	N/A	Number of times to run soil solution per model time step
Ulayer	int	N/A	Number of temperature nodes in upper layers
Llayer	int	N/A	Number of temperature nodes in bottom layer

Output Variables:

Variable

Type

Units

Description

layer

layer_data_struct *

N/A

Soil Variable Structure

modifies:

moist_thaw - thawed soil sublayer moisture
moist_froz - frozen soil sublayer moisture
moist - unfrozen soil sublayer moisture
ice - soil layer ice content
T - layer temperatures

energy

energy_bal_struct *

N/A

Energy Balance Structure

modifies:

T - temperature profile
fdepth - freezing and thawing depth
unfrozen - maximum unfrozen water
ice - frozen water content
Cs - volumetric heat capacity
kappa - thermal conductivity

Subroutines Called:

Modifications and Limitations

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