li><li>Define a constructor of this structure</li><li>Write a function to update the melt rate appropriately, and export this</li></ul><p>This is quite abstract, so let&#39;s do an example. We&#39;ll create a melt rate model which sets the melt rate as it is specified in the MISMIP+ experiment, where the melt rate on floating cells is <span>$0.2 \tanh((z_d - z_b)/75) \max(-100 - z_d,0)$</span>, where <span>$z_d$</span> is the ice shelf draft and <span>$z_d - z_b$</span> is the cavity thickness.  We&#39;ll f