Impact of subgrid-scale ice thickness distribution on heat flux on and through sea ice

► We evaluate the heat flux in an ice-ocean model with the ice thickness distribution. ► The conductive heat flux is underestimated when using grid-averaged thickness. ► The annual-mean bias is about 5 W m2 in the Arctic and 2 W m2 in the Southern Ocean. ► This bias becomes smaller when using a harmonic mean thickness.