What is meant by "saturation" in meteorological terms?

Saturation in meteorological terms refers to the state when the air contains the maximum amount of water vapor it can hold at a specific temperature and pressure. This concept is crucial in understanding humidity and the formation of clouds and precipitation. When air reaches this saturation point, it cannot hold any additional moisture, leading to the potential for condensation, cloud formation, or precipitation such as rain and snow.

At different temperatures, the capacity of air to hold moisture varies. For example, warmer air can hold more water vapor than cooler air, hence the saturation point also shifts with temperature changes. Recognizing the saturation point helps meteorologists predict weather patterns and phenomena more accurately.

The other options represent concepts that do not align with the definition of saturation. For instance, completely dry air does not indicate saturation, which implies a maximal state of humidity. Similarly, full cloud cover pertains to the observable state of clouds in the sky rather than the moisture capacity of the air, and the process of rain formation involves several stages that follow the point of saturation.