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REET L2 · Social Studies

Atmosphere, Air Pressure and Winds

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This page explains the layers of Earth's atmosphere, pressure belts, and the wind system from a REET exam angle. REET 2024 asked about El Niño, the Coriolis force, and the doldrums — core principles of physical geography.

  • 3 questions in REET 2024
  • Class 6–8 level
  • 9 min read
Verified 17 September 2026

How REET asks this topic

REET 2024 asked theory-based questions on this topic — the month El Niño typically appears, the latitude at which the Coriolis force is strongest, and the location of the doldrums. All of these rest on the basic principles of pressure and wind systems, so understand latitude-based concepts carefully.

Layers of the Atmosphere

Based on density and temperature, Earth's atmosphere is divided into five major layers — the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. The troposphere is the lowest layer, extending to about 18 km at the equator and about 8 km at the poles; all weather phenomena (clouds, rain, storms) occur in this layer.

The stratosphere extends to about 50 km and contains the ozone layer, which protects Earth from the sun's harmful ultraviolet (UV) rays. Above it lies the mesosphere (roughly 50–80 km), where temperatures are the coldest. The thermosphere (roughly 80–400 km) contains ionised particles that reflect radio waves, so its lower part is also called the ionosphere; the outermost layer is the exosphere, which gradually merges into space.

Pressure Belts

BeltLatitudeFeature
Equatorial low pressure (doldrums)0°–5° N and SIntense heat makes air rise; horizontal winds are weak
Sub-tropical high pressure (horse latitudes)around 30° N and SAir that rose at the equator descends here
Sub-polar low pressurearound 60°–70° N and SWarm and cold air masses collide, producing stormy weather
Polar high pressure70°–90° N and SExtremely cold, heavy, descending air

The Wind System and the Coriolis Force

Between pressure belts, air flows from high pressure to low pressure, giving rise to three main permanent winds — trade winds (from sub-tropical high pressure to equatorial low pressure), westerlies (from sub-tropical high pressure to sub-polar low pressure), and polar winds (from polar high pressure to sub-polar low pressure). These winds don't blow in a straight line — they curve, because of the Coriolis force caused by Earth's rotation.

The Coriolis force is proportional to the sine of the latitude — it is zero at the equator and reaches its maximum toward the poles. This is why winds curve to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This same force also determines the direction in which cyclones rotate.

El Niño: Key Facts

What it is
An abnormal warming of the sea surface in the Pacific Ocean, near the coast of Peru.
Usual timing
Appears around December (near Christmas time).
Effect
Affects monsoon and rainfall patterns in India and many other regions.

Jet Streams and Local Winds

Narrow bands of very fast-moving air near the upper boundary of the troposphere are called jet streams. The sub-tropical jet stream and the polar jet stream are the main ones; in India, the sub-tropical westerly jet stream and the tropical easterly jet stream that forms after it withdraws are considered important to understanding the arrival and retreat of the monsoon.

Besides these large-scale winds, there are also local winds that form from temperature differences over a limited area. The extremely hot, dry 'loo' that blows across the plains of north India in the afternoons during summer is a prime example — it raises the risk of heatstroke. In coastal areas, the 'sea breeze' that blows from the sea toward land during the day, and the 'land breeze' that blows from land toward the sea at night, are also examples of local winds, formed by the differing rates at which land and sea heat up and cool down.

Monsoon winds have the biggest influence on India's climate. From June to September, the south-west monsoon carries moisture from the Indian Ocean and brings rain to most of the country, while during October–December, as the monsoon retreats, north-easterly winds rising from the Bay of Bengal bring rain to the coastal region of Tamil Nadu. This is why Tamil Nadu receives most of its rainfall in winter, while the rest of India gets most of its rain toward the end of summer from the south-west monsoon.

Tropical cyclones are another important phenomenon linked to large differences in air pressure — a very low-pressure centre forms when the sea surface heats up, drawing in strong winds from all sides, which then start spinning due to the Coriolis force caused by Earth's rotation. In India, cyclones that form in the Bay of Bengal affect the east coast, and those that form in the Arabian Sea affect the west coast — and this rests on exactly the same pressure-wind principle covered above in this topic.

So the layers of the atmosphere, pressure belts, the wind system, and local winds are all connected ideas. REET aspirants should understand them as one chain rather than memorising them as separate sections — the sun's uneven heating creates differences in air pressure, those pressure differences drive winds, and Earth's rotation bends the direction of those winds.

How to teach this to children

Classroom activity

Throw a ball in a straight line across a spinning globe or rotating surface to give a simple demonstration of the Coriolis force — students can see how the path appears to curve on a rotating surface.

Teaching aid

A layered chart showing the atmosphere's layers by height, and a world map showing pressure belts and winds, are both useful.

Common misconception

Students often think temperature keeps rising with height, when in fact temperature falls with height in the troposphere — clarify this difference.

Assessment idea

Ask students what direction winds would blow if Earth did not rotate, and hold a short discussion.

Trick to remember

Remember the Coriolis force as 'zero at the equator, full at the poles' (sin 0° = 0, sin 90° = 1). Remember El Niño as the 'December child', since it appears around Christmas time.

REET 2024 Questions (with solutions)

Question 93

El – Nino generally originates in the month of

  1. Aदिसम्बर में
  2. Bमार्च में
  3. Cमई में
  4. Dसितम्बर में

Explanation

एल-नीनो (El Niño) पेरू के तट के पास प्रशांत महासागर की सतह के असामान्य रूप से गर्म होने की घटना है। यह सामान्यतः दिसम्बर में, क्रिसमस के आसपास प्रकट होती है, इसीलिए स्पेनिश में इसे 'El Niño' (शिशु/बाल ईसा) कहा गया। इसलिए उत्तर दिसम्बर है।

Question 121

The coriolis force which deflects the directions of the winds on the earth, is maximum at

  1. Aविषुवत वृत्त पर
  2. Bमध्य अक्षांशों पर
  3. Cध्रुवों पर
  4. Dपृथ्वी पर समान रहता है

Explanation

कोरिओलिस बल पृथ्वी के घूर्णन के कारण उत्पन्न होता है और यह अक्षांश की ज्या (sin φ) के समानुपाती होता है। इसलिए विषुवत वृत्त पर यह शून्य होता है और ध्रुवों पर अधिकतम। इसी कारण उत्तरी गोलार्ध में पवनें दाईं ओर और दक्षिणी गोलार्ध में बाईं ओर मुड़ती हैं।

Question 141

Doldrums is located on

  1. Aभूमध्य रेखा के उत्तर व दक्षिण में
  2. Bकर्क रेखा के उत्तर व दक्षिण में
  3. Cमकर रेखा के उत्तर व दक्षिण में
  4. Dआर्कटिक वृत्त के उत्तर व दक्षिण में

Explanation

शान्त कटिबन्ध (Doldrums) भूमध्य रेखा के दोनों ओर लगभग 5° उत्तर से 5° दक्षिण अक्षांशों के बीच स्थित निम्न वायुदाब की पेटी है। यहाँ तेज गर्मी से वायु ऊपर उठती है, इसलिए धरातल पर क्षैतिज पवनें बहुत कमजोर होती हैं और शान्त स्थिति रहती है। कर्क व मकर रेखा के आसपास (लगभग 30° अक्षांश) उपोष्ण उच्च दाब की ‘अश्व अक्षांश’ पेटियाँ होती हैं।

Practice Questions

Question 1

Which is the lowest layer of the atmosphere?

  1. Aसमतापमंडल
  2. Bक्षोभमंडल
  3. Cमध्यमंडल
  4. Dतापमंडल

Explanation

The troposphere is the lowest layer, starting right from Earth's surface, and it's where all weather phenomena occur.

Question 2

In which layer of the atmosphere is the ozone layer found?

  1. Aक्षोभमंडल
  2. Bसमतापमंडल
  3. Cमध्यमंडल
  4. Dबहिर्मंडल

Explanation

The ozone layer sits within the stratosphere and protects Earth from ultraviolet rays.

Question 3

Where is the magnitude of the Coriolis force the greatest?

  1. Aभूमध्य रेखा पर
  2. Bउपोष्ण अक्षांशों पर
  3. Cध्रुवों पर
  4. Dसभी जगह समान

Explanation

The Coriolis force is proportional to the sine of latitude, so it is maximum at the poles and zero at the equator.

Question 4

At which latitude is the calm belt (doldrums) located?

  1. A30° उत्तर-दक्षिण
  2. B5° उत्तर-दक्षिण (भूमध्य रेखा के निकट)
  3. C60° उत्तर-दक्षिण
  4. Dध्रुवों पर

Explanation

The doldrums are a low-pressure belt located within about 5° latitude on either side of the equator.

Question 5

The El Nino phenomenon generally occurs in which ocean?

  1. Aहिंद महासागर
  2. Bप्रशांत महासागर
  3. Cअटलांटिक महासागर
  4. Dआर्कटिक महासागर

Explanation

El Niño is the abnormal warming of the Pacific Ocean's surface near the coast of Peru.

Question 6

In which direction do the trade winds blow?

  1. Aउपोष्ण उच्च दाब से भूमध्यरेखीय निम्न दाब की ओर
  2. Bध्रुवीय उच्च दाब से भूमध्य रेखा की ओर
  3. Cउपध्रुवीय निम्न दाब से ध्रुव की ओर
  4. Dभूमध्य रेखा से ध्रुव की ओर सीधी

Explanation

Trade winds blow from the sub-tropical high-pressure belt toward the equatorial low-pressure belt.

Question 7

Due to the Coriolis force, in which direction do winds deflect in the Northern Hemisphere?

  1. Aबाईं ओर
  2. Bदाईं ओर
  3. Cसीधी रहती हैं
  4. Dदिशा नहीं बदलती

Explanation

Because of the Coriolis force, winds curve to the right in the Northern Hemisphere, and to the left in the Southern Hemisphere.

Question 8

The Horse Latitudes are which type of pressure belt?

  1. Aभूमध्यरेखीय निम्न दाब
  2. Bउपोष्ण उच्च दाब
  3. Cउपध्रुवीय निम्न दाब
  4. Dध्रुवीय उच्च दाब

Explanation

The horse latitudes are the sub-tropical high-pressure belt located at around 30° N and S.

Question 9

The most suitable way to explain an abstract concept like the Coriolis force in class is

  1. Aकेवल परिभाषा बोर्ड पर लिखना
  2. Bघूमते ग्लोब या गोल सतह पर सरल भौतिक प्रदर्शन करवाना
  3. Cकोई उदाहरण न देना
  4. Dविषय छोड़ देना

Explanation

A physical demonstration on a spinning globe or rotating surface makes an abstract scientific-geographic principle concrete and understandable for Class 6-8 students.

Question 10

If students hold the misconception that temperature always rises with increasing altitude, what should the teacher do?

  1. Aभ्रांति को नज़रअंदाज करना
  2. Bक्षोभमंडल के तापमान परिवर्तन का वास्तविक चार्ट/ग्राफ दिखाकर स्पष्ट करना
  3. Cछात्र को गलत बताकर आगे बढ़ना
  4. Dटॉपिक दोबारा न पढ़ाना

Explanation

Showing an actual temperature-height chart or graph lets students see for themselves that temperature falls with height in the troposphere, clearing up the misconception.

Frequently Asked Questions

Which is the lowest layer of the atmosphere, and what happens in it?+

The troposphere, where all weather phenomena (clouds, rain, storms) occur.

Which layer of the atmosphere contains the ozone layer?+

The stratosphere.

Where is the Coriolis force strongest, and where is it zero?+

Strongest at the poles, zero at the equator.

Where are the doldrums located?+

A low-pressure belt on either side of the equator, roughly within 5° latitude.

In which month does El Niño usually appear?+

In December, around Christmas time.

Read next

Movements of the Earth

Previous topic: the movements of the Earth.

Eclipses

Next topic: eclipses.

REET Syllabus

See the complete REET Level 1 and Level 2 syllabus in one place.

REET 2024 Solved Paper

Practice all of REET 2024's solved questions, subject by subject.

Change Log

  • 17 September 2026 — English page published — mirrors the fact-checked Hindi page, independently bilingual-accuracy checked