How ice grows from premelting films and water droplets

11 pags., 5 figs.Close to the triple point, the surface of ice is covered by a thin liquid layer (so-called quasi-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 premelting 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 undetectably beneath the droplet. Our approach is a general framework that naturally models freezing close to three phase coexistence and provides a first principle theory of ice growth and melting which may prove useful in the geosciences.L.G.M. is grateful to Loughborough University for hosting a stay funded by the “Programa Estatal de Promoción del Talento y su Empleabilidad en I+D+i” of the Spanish Ministerio de Educación, Cultura y Deporte (Plan Estatal de Investigación Científica y Técnica y de Innovación 2013–2016). We acknowledge the computer resources at MareNostrum and the technical support provided by BSC/MN (QCM-2017-2-0008, QCM-2017-3-0034). P.L., E.G.N., and L.G.M. were funded by the Spanish Agencia Estatal de Investigación under grant FIS2017-89361-C3-2-P and DNS by EPSRC grant EP/R006520/1