the growth and melt rate are also affected by the state of the ice itself. during growth, the ice thickening due to freezing (as opposed to dynamics) is itself dependent on the thickness, so that the ice growth slows as the ice thickens. likewise, during melt, thinner sea ice melts faster. this leads to different behaviour between multiyear and first year ice. in addition, melt ponds on the ice surface during the melt season lower the albedo such that more solar radiation is absorbed, leading to a feedback where melt is accelerated. the presence of melt ponds is affected by the permeability of the sea ice- i.e. whether meltwater can drain- and the topography of the sea ice surface, i.e. the presence of natural basins for the melt ponds to form in. first year ice is flatter than multiyear ice due to the lack of dynamic ridging, so ponds tend to have greater area. they also have lower albedo since they are on thinner ice, which blocks less of the solar radiation from reaching the dark ocean below.