How ice grows: role of surface liquid films and water droplets

Close to the triple point, the surface of ice is covered by a thin liquid layer which crucially impacts growth and melting rates. Experimental probes cannot observe the growth processes below this layer, and classical models of growth by vapor deposition do not account for the formation of these wetting films. Here, we develop a mesoscopic model of liquid-film mediated ice growth, and identify the various resulting growth regimes. At low saturation, freezing proceeds by terrace spreading, but the motion of the buried solid is conveyed through the liquid to the outer liquid-vapor interface. At higher saturations water droplets condense, a large crater forms below, and freezing proceeds undetectable beneath the droplet. Our approach is a generalized framework that naturally models freezing close to three phase coexistence and provides a first principle theory of ice growth and melting that is much need in the geosciences.