Evolution of the time derivative of the relative helicity H_r when calculated above z = 0 in the solar atmosphere using Eq. (13). The total time derivative (black solid line) is split into the dissipation term (purple solid line), the surface correction term (yellow solid line), the shear term (red solid line) and emergence term (blue solid line). The dashed black line is the derivative of the curve from Fig. 17 calculated using finite differencing.