Sublimation of Water Vapor

(meteorology), the direct transition of atmospheric water vapor into the solid phase—ice or snow. The process may occur at subfreezing air temperatures, when the vapor pressure of water exceeds the saturation vapor pressure relative to the surface of the ice.

Sublimation occurs both in the free atmosphere and on the earth’s surface and terrestrial objects. In the atmosphere, water vapor sublimes onto frozen droplets, snowflakes, and certain solid particles. At temperatures below –40°C, sublimation of water vapor onto any particles and onto groups of water molecules is apparently possible. The product of the sublimation of water vapor in the atmosphere is ice crystals, which then grow into snowflakes. Rime and hoarfrost are formed on the earth’s surface and terrestrial objects.

Sublimation of water vapor plays an important role in the formation of clouds and atmospheric precipitation.