Discuss the concept of air mass and explain its role in macro-climatic changes.

According to meteorology, an air mass is a large volume of air having uniform temperature, pressure, and water vapor content. It can cover a large proportion of area by the adaption of the characteristics of the surface present below it.

Classification: Air masses are classified into four categories according to their place of formation i.e. arctic (cold type and formed in the arctic region), polar (cold type and formed in higher latitude), tropical (slightly warm and formed in lower latitude), and equatorial (warm type and formed in the equatorial region).

Formation: The formation of air mass depends on the temperature and moisture properties of a surface (land or sea surface) with which the air is in contact for an adequate period of time.

Macro Climatic Changes:

• When a warm air mass gets placed between two cold air masses, then the warm air mass starts rising and the formation of an occluded front takes place. It causes a mixture of cold and warm front type weather.
• When air mass originates in the coastal areas, it contains more humid content which causes heavy precipitation.
• Near the boundary between warm and cool air masses, a low-pressure area forms which causes cyclonic storms.
• When the air masses start cooling more than their surrounding areas, it makes the air denser and forms anticyclone.
• The latent heat, transferred by the air mass causes heat imbalance.

This is how air mass causes macro-climatic changes.