Source region
Topic: Air Masses, Fronts, Cyclones and Thunderstorms · NCERT: Class 11, Ch 9 "Atmospheric Circulation and Weather Systems"
Meaning
A source region is the large, uniform surface where an air mass forms. Air resting over it for a long time takes on its temperature and moisture. A good source region is wide and even, such as a vast ocean, a desert or a snow-covered plain. Mountains and broken land are not source regions, because their surfaces keep changing. NCERT lists five: warm tropical and subtropical oceans, subtropical hot deserts, cold high-latitude oceans, snow-covered high-latitude continents, and the permanent ice of the Arctic and Antarctica.
Example
The Siberian Plain in northern Asia is a source region. Its wide, snow-covered land produces cold, dry continental polar air. The Himalaya, the Deccan plateau and equatorial forests are not source regions.
Don't confuse with
- Air mass: the source region is the surface where the air gets its character. The air mass is the body of air that forms there and later moves away.
Related concepts
- Air mass
- Maritime tropical air mass
- Continental tropical air mass
- Maritime polar air mass
- Continental polar air mass
- Continental arctic air mass