The following six ideal generating regions of air – masses are found on the earth:
1. Polar ocean area (the northern region of the Atlantic and Pacific Ocean) – In these areas, the air – masses are produced during the winter.
2. Sub – Polar continental zone (glaciated part of Eurasia and North America and Arctic region) – In these areas, the air – masses arise during the winter period.
3. Monsoon Area (South – East Asia) – This includes India, Bangladesh, Indonesia, Indo – China region.
4. Tropical ocean area (anticyclone area – winter and summer).
5. Tropical continental region (Mississippi Valley Area of North America, Asia and North Africa).
6. Equatorial linear areas – Air – masses originate in these areas due to convectional conditions.