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 — tips:firnheating [2013/05/06 15:27] (current)mschafer created 2013/05/06 15:27 mschafer created 2013/05/06 15:27 mschafer created Line 1: Line 1: + ====== 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 + 