American Meteorological Society Certification (AMS) 2025 – 400 Free Practice Questions to Pass the Exam

An air mass is defined as a large volume of air that possesses uniform temperature and humidity characteristics throughout its extent. This homogeneity results from the air mass spending time over a particular region, where it can acquire the local temperature and moisture properties of that area.

For instance, when an air mass forms over a tropical ocean, it generally becomes warm and humid, while an air mass forming over a polar region tends to become cold and dry. These characteristics can significantly influence the weather patterns when the air mass moves and interacts with other air masses or geographic features.

Understanding air masses is crucial because they are the building blocks for weather systems. While smaller air volumes or compact structures of gases might refer to different meteorological phenomena, they do not capture the essence of what constitutes an air mass. Similarly, referring to it as merely a weather system overlooks the specific criteria of temperature and humidity uniformity that define an air mass.