Chapter 7, Problem 1LC

To determine

The formation of air mass.

Answer to Problem 1LC

The formation of air mass occurs over an extensive, uniform land or sea surface on the Earth that are associated with stationary or anticyclonic air. An air mass form in distinct source regions that are favorable for its generation.

Explanation of Solution

An air mass is a huge air parcel that has relatively uniform properties in the horizontal dimension and migrates as an entity. Such extensive bodies are different from one another and they compose the troposphere.

Formation of air mass: An air mass forms when a parcel of air remains in a large, uniform land and sea surface for an extended period to achieve uniform properties. Such regions are termed as source regions. Some of the ideal source regions are uniform covering of snow, forest or desert. These source regions are parts of Earth’s surface well suited for the formation of air masses, as they are wide, physically uniform, and are associated with air that is stationary or anticyclonic.

Warm air masses can develop in any season over the waters of the southern North Atlantic, the Gulf of Mexico/Caribbean Sea, and the southern North Pacific, and in summer, they can develop over the deserts of the southwestern United States and northwestern Mexico. Cold air masses form over the northern parts of the Atlantic and Pacific Oceans and over the snow-covered lands of north-central Canada.