Mixed-phase clouds in polar regions play a crucial role in surface ice melting. To accurately predict their radiative impact in climate models, an accurate representation of their microphysical structure is required. However, cloud ice content is generally underpredicted in models, when primary ice nucleation is constrained with measurements. Apart from uncertainties in primary ice formation, another possible explanation for this discrepancy is that most models underestimate secondary ice production. In this study we implement missing secondary ice production mechanisms in the Norwegian Earth System Model version 2 and investigate their impact on the representation of Arctic clouds observed at Ny-Alesund.