What is sublimation in the context of atmospheric processes?

Sublimation refers to the process where a substance transitions directly from a solid state to a gaseous state without passing through a liquid state. In the context of atmospheric processes, this specifically applies to ice, which can change directly into water vapor.

In option B, the transformation of water vapor directly into ice is a process known as deposition, which is distinct from sublimation. Sublimation would instead involve ice turning directly into water vapor. The process can be commonly observed in nature, especially in snowy regions where snow can diminish over time without melting into liquid water.

The other options pertain to different states of matter that involve transitions but do not capture the essence of sublimation. Conversion of liquid water to vapor is evaporation, which is not relevant to the solid-gas transition of sublimation. Evaporation of frozen water suggests the process is melting into liquid first, and melting of ice to form liquid water again describes a different phase transition entirely. Hence, recognizing sublimation involves understanding it as a direct change from solid ice to vapor, making B a logical choice for the context when discussing the transition of states.