SSC CGL Geography · Climatology, Atmosphere and Weather
Atmosphere and Temperature
What the air is made of, the layers of the atmosphere and what happens in each, auroras, and the words used for daily and city temperatures.
Why this matters
Twelve questions in the bank, and nine of them come from the 2025 shifts: the layers of the atmosphere were a new favourite in 2025. Each one pairs a layer with what happens in it, so learn the five layers in order with one fact each.
Concept 1 of 2: Layers and composition of the atmosphere
Definition
Composition of dry air: nitrogen 78%, oxygen 21%, argon about 0.93%, and a little carbon dioxide.
The layers, from the ground up:
- Troposphere: almost all weather and clouds.
- Stratosphere: the ozone layer, which absorbs the Sun's ultraviolet rays.
- Mesosphere: meteors burn up here.
- Thermosphere: heated by the Sun's ultraviolet and X-rays, more so in solar storms; the International Space Station orbits here.
- Exosphere: the thin outer edge.
The Karman line, about 100 km up, is taken as the edge of space. Auroras near the poles come from the solar wind meeting the Earth's magnetic field.
Practise this conceptself-check · 4 quick reps
The same idea in a real exam question:
Example 1 · Climatology, Atmosphere and Weather · Atmosphere and Temperature
Clouds are in the troposphere
Concept 2 of 2: Temperature words
Definition
The terms:
- Diurnal range: the difference between the day's highest and lowest temperature. The annual range compares the warmest and coldest months.
- Urban heat island: a city is hotter than the land around it because concrete and asphalt store heat, there is little vegetation, and vehicles add heat.
- Southern India lies in the tropics with sea on three sides, so its range of temperature is small. Coastal places have the smallest ranges.
- Al Aziziyah (Libya) recorded 58 °C in 1922, long quoted as the world's highest shade temperature.
Practise this conceptself-check · 3 quick reps
The same idea in a real exam question:
Example 2 · Climatology, Atmosphere and Weather · Atmosphere and Temperature
The tropical south has an even temperature
Summary — formulas & gotchas at a glance
A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.
Reference tables (2)
Watch out for (2)
- Clouds are in the troposphere→ Layers and composition of the atmosphere
- The tropical south has an even temperature→ Temperature words
Test yourself on Climatology, Atmosphere and Weather
15 past SSC CGL questions from this chapter, timed at 9 minutes and marked the way the exam marks it. You see your score and every answer the moment you finish. Free to start.