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tips:firnheating [2013/05/06 15:27] (current)
mschafer created
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 +====== 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).
  
 +<​code>​
 +$ 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
 +</​code>​
tips/firnheating.txt ยท Last modified: 2013/05/06 15:27 by mschafer
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