1. Origin and Properties:

* They form over large, relatively uniform areas: Air masses develop over regions with similar characteristics like temperature, humidity, and pressure. For example, a maritime tropical air mass forms over warm ocean waters.

* They acquire the characteristics of their source region: Air masses take on the temperature, humidity, and other properties of the surface over which they form. This is why maritime air masses are generally moist, while continental air masses are typically dry.

2. Behavior and Movement:

* They tend to move horizontally: Air masses move due to pressure differences in the atmosphere, often flowing from areas of high pressure to low pressure.

* They modify the weather of the areas they pass over: As air masses move, they bring their characteristics to new locations, influencing temperature, precipitation, and other weather patterns.

3. Classification:

* They are classified based on their source region and temperature: Air masses are categorized using two letters, the first indicating their source region (c - continental, m - maritime) and the second indicating their temperature (A - Arctic, P - Polar, T - Tropical, E - Equatorial).

4. Interactions:

* They interact with each other at boundaries called fronts: When air masses of different characteristics meet, they form fronts. These fronts can cause significant weather changes like thunderstorms, rain, or snow.

It's important to note: While air masses share similarities, they are also distinct entities with different characteristics. The specific properties of an air mass depend on its source region and the time it spends over that region.