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

(b) Air masses are characterized by uniform temperature and pressure of mass of air over a large area.

Conditions for formation

=> Large area e.g. Sahara desert

=> Anticyclonical conditions to cause subsidence of air e.g. Sub tropical region.

=> Stay of air over same area for longer time

=> high pressure with little pressure difference

Source region of air masses: (5 major)

Types of air masses

=> (1) Continental tropical (CT)

=> (2) Continental polar (CP)

=> (3) Continental Arctic (CA)

=> (4) maritime tropical (mT)

=> (5) maritime polar (mP)

Continental=> dry | tropical=> warm

maritaime=> moist | Polar/Arctic=> cold

Role in macro climate:

They cause precipitation in area of front.