What are the two key characteristics used to identify an airmass?

An airmass is defined primarily by temperature and moisture content. These two characteristics are crucial because they determine the properties of the air that can influence weather patterns and conditions in a given area.

Temperature reflects the thermal profile of the airmass, identifying whether it is warm or cold, while moisture indicates how much water vapor the airmass contains, determining whether it is dry or humid. The combination of these factors helps meteorologists classify airmasses into categories such as tropical (warm and moist), polar (cold), or continental (dry), among others. Understanding these characteristics is vital in forecasting weather, as different airmasses can lead to varied effects in terms of precipitation, cloud formation, and temperature changes.

The other options, while related to weather phenomena, do not directly pertain to the identification of airmasses in the same fundamental way.