Thermodynamic Properties

On this page one can find SIF inputs for thermodynamic properties. The following properties are given below:

  • Heat Capacity of ice as a function of temperature
  • Heat Conductivity of ice as a function of temperature
  • Pressure Melting Point of ice as a function of absolute pressure
  • Pressure Melting Point of ice as a function of hydrostatic pressure
  • Surface Temperature as a function of Longitude/Latitude and elevation

TODO: link with iceflowproperties.f90 ?

Heat Capacity

Heat Capacity of ice as a function of temperature:

!! in SI units, input in Kelvin
$ function capacity(T) { _capacity=146.3+(7.253*T)}

and its call from within the Material section

!! in SI units, input Kelvin
Heat Capacity = Variable Temperature
    Real MATC "capacity(tx)"

!! in scaled units (m-MPa-years)
!! input Kelvin
Heat Capacity = Variable Temperature
    Real MATC "capacity(tx)*(31556926)^(2.0)"

Heat Conductivity

Heat Conductivity of ice as a function of temperature 1):

!! in SI units, input in Kelvin
$ function conductivity(T)  { _conductivity=9.828*exp(-5.7E-03*T)}

and its call from within the Material section

!! in SI units, input Kelvin
Heat Conductivity = Variable Temperature
 Real MATC "conductivity(tx)"

!! in scaled units (m-MPa-years)
!! input Kelvin
Heat Conductivity = Variable Temperature
 Real MATC "conductivity(tx)*(31556926)*1.0E-06"

Pressure Melting Point

Pressure Melting Point of ice as a function of absolute pressure:

!! pressuremeltingpoint (Pressure in MPa)
$ function pressuremeltingpoint(PIN) {\
  P = PIN;\
  if (P<0.0) P=0.0;\
  beta=9.8E-08*1.0E06;\
  _pressuremeltingpoint=273.15-(beta*P);\
}

and its call from within the Material section (call for instance as upper limit for the TemperateIce solver)

Temp Upper Limit = Variable Pressure
    Real MATC "pressuremeltingpoint(tx)"

Pressure Melting Point

Pressure Melting Point of ice as a function of hydrostatic pressure (input variable is flow depth):

!! pressuremeltingpoint (in SI units)
$ function pressuremeltingpoint2(D) {\
  P = 910*D*9.81;\
  if (P<0.0) P=0.0;\
  beta=9.8E-08;\
  _pressuremeltingpoint2=273.15-(beta*P);\
}

and its call from within the Material section (call for instance as upper limit for the TemperateIce solver):

Temp Upper Limit = Variable Depth
    Real MATC "pressuremeltingpoint2(tx)"

Surface Temperature

Surface Temperature as a function of Longitude/Latitude and elevation

$ function surfacetemp(X) { _surfacetemp = 34.36 + 273.15  - 0.68775 * abs(X(0)) - 9.14E-03 * X(1) }
$ function phyd(Z) { _phyd = 9.81 * Z * 918.0}

with the longitude/latitude defined the call in the corresponding boundary condition of the free surface reads as follows

Temperature = Variable Latitude, Coordinate 3
     Real MATC "surfacetemp(tx)"
1)
after: Ritz, C. 1987. Time dependent boundary conditions for calculation of temperature fields in ice sheets. In: E. D. Waddington and J. S. Walder (Eds.), The Physical Basis of Ice Sheet Modelling, IAHS Publication No. 170, pp. 207–216. IAHS Press, Wallingford, UK.
tips/thermoprop.txt · Last modified: 2013/03/08 07:04 by gag
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