SSC CGL - Detailed Guide 2025

Self-Paced Course

Climatology

Reference: Lucent GK, NCERT Class 6–12

Water Vapor and Dust Particles are variable and significant for weather processes.

Layer	Altitude	Key Features
Troposphere	0-12 km	Weather phenomena occur here; temperature ↓ with altitude; densest layer
Startosphere	12–50 km	Contains ozone layer; temperature ↑ with altitude; ideal for flying aircraft
Mesosphere	50–80 km	Coldest layer; meteors burn here
Thermosphere	80–500+ km	Temperature ↑ sharply; contains ionosphere (radio communication)
Exosphere	500+ km	Outermost layer; merges with outer space

The balance between incoming solar radiation and outgoing terrestrial radiation.

Component	Percentage
Incoming solar radiation (Insolation)	100%
Reflected by atmosphere & clouds	35% (Albedo)
Absorbed by atmosphere & clouds	14%
Absorbed by Earth's surface	51%

Outgoing radiation is in the form of long-wave (infrared) radiation.

Horizontal: Equator is hottest, poles are coldest.
Vertical: Temperature generally decreases with height (~6.5°C/km).
Factors influencing Temperature
- Latitude
- Altitude
- Distance from sea
- Ocean currents
- Wind & Cloud cover
- Nature of land surface

Type	Direction	Region
Trade Winds	NE in Northern Hemisphere, SE in Southern Hemisphere	0°–30° Latitude
Westerlies	SW in Northern Hemisphere, NW in Southern Hemisphere	30°–60° Latitude
Polar Easterlies	From poles to sub-polar regions	60°–90° Latitude

Monsoons: Winds that change direction with season.
- Summer Monsoon (June–Sept): From ocean to land (SW monsoon)
- Winter Monsoon (Oct–Feb): From land to ocean (NE monsoon)

Wind	Location	Effect/ Feature
Loo	North India (Summer)	Hot and dry
Chinook	Rockies (USA/Canada)	Warm, snow-melting wind
Foehn	Alps (Europe)	Warm and dry
Mistral	France	Cold and dry
Harmattan	West Africa	Dry, dusty, blows toward the sea

Belt	Latitude	Nature
Equatorial Low	Around 0°	Low pressure (rising air)
Subtropical High	~30° N & S	High pressure (descending air)
Subpolar Low	~60° N & S	Low pressure
Polar High	Around 90° N & S	High pressure (cold, dense air)

Wind moves from high to low pressure. Coriolis force deflects direction.

Narrow bands of fast-moving air in upper troposphere.
Found near boundaries of pressure belts (especially 30° & 60° latitudes).
Move west to east (westerlies).
Important for:
- Influencing monsoons
- Aviation routes
- Development of cyclones

Feature	Details
Location	5°–20° latitude (rare near Equator)
Origin	Warm oceans (>27°C), low pressure
Structure	Eye (calm), eyewall (maximum wind)
Speed	Slow (~15–30 km/h)
Examples	Cyclone Fani, Cyclone Yaas (India)
Regional Names	Hurricane (USA), Typhoon (Asia), Cyclone (India), Willy-Willy (Australia)

Feature	Details
Location	35°–65° latitude (westerly belt)
Origin	Along polar front, between warm and cold air masses
Structure	Frontal system: warm front & cold front
Speed	Faster (~60 km/h)
Duration/Spread	Lasts longer and covers larger area than tropical cyclones
Weather Caused	Cloudy skies, moderate to heavy rainfall

Type	Definition	Condition
Rain	Water droplets falling from clouds	Common in tropical and temperate zones
Snow	Ice crystals falling when temperature < 0°C	Cold regions, high altitudes
Hail	Ice pellets formed by strong updrafts in cumulonimbus clouds	Common in thunderstorms

Type	Cause	Region
Convectional	Intense heating of land, air rises & cools	Equatorial regions
Orographic	Moist air forced up by mountains	Western Ghats (India), Andes
Frontal	Warm and cold air masses meet	Temperate cyclones, mid-latitudes

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