Firn heating

Firn heating (latent heat through refreezing of percolating meltwater) following
Wright, A. P., J. L. Wadham, M. J. Siegert, A. Luckman, J. Kohler, and A. M. Nuttall (2007), Modeling the refreezing of meltwater as superimposed ice on a high Arctic glacier: A comparison of approaches, J. Geophys. Res., 112, F04016, doi:10.1029/2007JF000818
can be implemented in the following way. Make sure that the mesh contains enough layers close to the upper surface (for example by adding a boundary layer with ExtrudeMesh).

$ function refreezing(D,z) { \
  Dfirn=11.5;\ !or some non constant function
  if (Dfirn < 0) { Dfirn=0.0; }\
  Tann=-7.684-0.004*z;\ !values from data
  Twin=-15.0-0.004*z;\ !values from data
  freezing=0.0;\
  if (D > (Dfirn - 0.00001)) { freezing=0.0; }\
    else { \
     Tw=((D/Dfirn) - 1.0)*(Tann - Twin) + Tann;\
     Ts=Tann*sqrt((1.0 - ((D - Dfirn )^2)/Dfirn^2));\
     freezing = 910.0*capacity(Tann+273.15)*(Ts-Tw)*1e-6; }\ !check your unit system
  if (freezing < 0.0) {_refreezing=0.0; }\
    else {_refreezing=freezing; }\
}

Body Force 1
...
 Temp Volume Source = Variable Depth, Coordinate 3
     Real MATC "refreezing(tx(0), tx(1))"
End
tips/firnheating.txt · Last modified: 2013/05/06 18:27 by mschafer
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