Air Masses & Fronts for pms and css in 2025 notes

“Physical & General Geography (Paper I) for CSS & PMS” By Imran Bashir
In the Name of
Allah,
the Boundlessly Merciful, the Infinitely
Compassionate. Praise be to Allah, the Lord of the
worlds; and peace and blessings of Allah be upon
His Prophet
Muhammed

AIR MASSES, FRONTS
“Geography for CSS / PMS ………. Author: Imran Bashir”

Air Mass..... Introduction
An air mass is a large mass of air having
similar temperature and moisture
characteristics over its horizontal extent.
An air mass occupies thousands of square
miles of the Earth's surface.

Source Region
• The part of earth where air masses acquire their
distinguish qualities are called source regions.

The Abbreviations Used to Classify Air
Masses
Word Means
c
m
T
P
A
Continental Dry
Maritime Moist
Tropical warm
Polar Cold
Arctic Very cold

Warm and Moist Cold and Dry

• Air masses are classified according :
• 1. Latitudinal position
• 2. Underlying surface
AIR MASS CLASSIFICATION

• With respect to “Latitudinal Positions”, five
types of air masses are as follows:
Air Mass Symbol Source Regions
Arctic A Arctic Ocean and fringing (bordering) lands
Antarctic AA Antarctica
Polar P Continents and oceans (50 – 60 North and
South)
Tropical T Continents and oceans (20 – 35 North and
South)
Equatorial E Oceans close to equator

• With respect to “Underlying Surface”, two
further sub-divisions are imposed on the
preceding type as follows:
Air Mass Symbol Source Regions
Maritime M Oceans
Continental C Continents

• By combining types based on “Latitudinal Positions”
with those based on “Underlying Surface”, a list of six
important air masses results as under:
Air Mass Symbol Properties
Continental Arctic cA Cold, dry
Continental Antarctic cAA Very cold, very dry (winter)
Continental Polar cP Cold, dry (winter)
Maritime Polar mP Cold, moist (winter)
Continental Tropical cT Warm, dry
Maritime Tropical mT Warm, moist
Maritime Equatorial mE Warm, very moist

•Source Areas
•Typical Characteristics
1. CONTINENTAL ARCTIC AND
ANTARCTIC (CA&CAA)
•Source Areas
•Typical Characteristics
2.CONTINENTAL POLAR (CP)

• Source Areas
• Typical Characteristics
3.MARITIME POLAR (MP)
• Source Areas
4.CONTINENTAL TROPICAL (CT)

• Source Areas
5. MARITIME TROPICAL (MT)
• The name maritime equatorial is sometimes applied to very
moist and warm air masses, originating within a few degrees
of equator. These are a pronounced form of maritime tropical
air masses. This air mass holds about 200 times as much
water vapour as the extremely cold Arctic and Antarctic air
mass
6. MARITIME EQUATORIAL (ME)

Global Distribution of Air Masses

AIR MASSES OF NORTH AMERICA

What is a Front?
• Simply, we can say that the line of contact
along the separation plane between air
masses and the surface is termed as a
Front.

1. Cold Front
A frontal contact zone
in which cold air is
invading warm air zone
is termed as a “cold
front”.

Weather Associated with Cold Front

2. Warm Front
A warm front is that
in which warm air is
moving into a
region of colder air.

Weather Associated with Warm Front

3. Occluded Fronts
Cold fronts normally move along the ground at a
faster rate than warm fronts. Hence, when both
types are in the neighbourhood, as they are in the
cyclonic storms, the cold front may overtake the
warm front. An “occluded front” then results. The
colder air of the fast-moving cold front remains
next to the ground, forcing both the warm air and
the less cold air to rise over it. The warm air mass is
lifted completely free of the ground.

Air Masses & Fronts for pms and css in 2025 notes

More Related Content

Recently uploaded (20)

Featured (20)

Air Masses & Fronts for pms and css in 2025 notes