We present measurements of growth rates of the (0001) facet surface of ice as
a function of water vapor supersaturation over the temperature range −2≥T≥−40 C. From these data we infer the temperature dependence of premelting
on the basal surface and the effects of premelting on the ice growth dynamics.
Over this entire temperature range the growth was consistent with a simple 2D
nucleation model, allowing a measurement of the critical supersaturation
σ0(T) as a function of temperature. We find that the 2D nucleation
barrier is substantially diminished when the premelted layer is partially
developed, as indicated by a reduced σ0, while the barrier is higher
both when the premelted layer is fully absent or fully developed