over the melt rate models instantiated above. Each time, we make a WAVI.jl <code>Model</code> with the appropriate melt rate parametrization specified via the <code>melt_rate</code> keyword.  We use the <code>update_state!</code> method to bring the melt (as well as all other quantities, such as the grounded fraction) in line with the specified thickness, and then plot the melt rate. (We also set the number of Picard iterations to 1 – each time we do an <code>update_state!</code> we perform a velocity sol