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Playbook

Climatology, Atmosphere and Weather

57 q · 28% HARD — the densest-HARD chapter. Atmospheric Layers (14 · 21% HARD — troposphere/stratosphere/mesosphere/thermosphere, aurora), Cyclones, Fronts and Local Winds (14 · 29% HARD — tropical vs extratropical cyclones, named local winds), Humidity + Clouds + Precipitation (10), Climate Classification (8 · 38% HARD — Koeppen zones), Atmospheric Pressure + Winds (6 · 50% HARD — Coriolis, trade winds, jet streams), Insolation + Temperature (5). Apply strand because mechanism-tracing dominates: cyclogenesis, monsoon dynamics, pressure-belt formation.

questions in the bank
57
tagged HARD
28%
subtopic(s)
6
worked examples
2

When you’ll see it

An atmospheric-layer question (troposphere/stratosphere identification, ozone layer, aurora region), a cyclone question (tropical vs extratropical, eye-wall, Coriolis effects), a humidity/cloud/rainfall question, a Koeppen climate-zone identification, a pressure-belt or trade-wind question, or a temperature-inversion / solar-geometry question.

How this chapter is tested

57 q in 10 years, 28% HARD — the densest-HARD chapter in NDA Geography. Atmospheric Layers (14 q · 21% HARD): troposphere (0–12 km, weather happens here, temperature DECREASES with altitude at ~6.5°C/km lapse rate, contains 75% of atmospheric mass + nearly all water vapour), stratosphere (12–50 km, OZONE LAYER 20–30 km, temperature INCREASES with altitude due to ozone absorbing UV — that's why ozone destruction matters), mesosphere (50–80 km, coldest layer, meteors burn here), thermosphere (80–600 km, temperature INCREASES again to 2000°C, AURORAS occur here at 100–300 km, ionosphere overlaps), exosphere (600+ km, satellites orbit). Auroras: Aurora Borealis (N hemisphere, near magnetic N pole), Aurora Australis (S hemisphere). Caused by solar-wind charged particles interacting with magnetic-field-trapped gases.

Cyclones, Fronts and Local Winds (14 q · 29% HARD) tests cyclogenesis. TROPICAL cyclones: form 5°–30° latitude (NOT at equator — Coriolis ≈ 0 there can't initiate spin), need warm ocean ≥27°C + moist air, NO fronts (uniform tropical air mass), winds rotate counterclockwise N hemisphere (clockwise S), have an EYE (calm center, low pressure ~900 hPa). Named regionally: hurricane (Atlantic/E Pacific), typhoon (NW Pacific), cyclone (Indian Ocean), willy-willy (Australia). EXTRATROPICAL cyclones: mid + high latitudes (30°–60°), driven by fronts (cold + warm air masses), much larger area than tropical, no warm core, no distinct eye, driven by jet streams + temperature gradients. The 2026 NDA-1 PYQ tests this distinction. Local winds: Loo (hot dry NW summer wind in N India), Kalbaisakhi (pre-monsoon thunderstorms in WB+Assam), Chinook (warm dry wind down lee side of Rockies, melts snow → 'snow eater'), Foehn (Alpine equivalent of Chinook), Mistral (cold N wind down Rhône valley in France), Sirocco (hot dry wind from Sahara → S Europe), Harmattan (dry dust-laden wind W Africa), Santa Ana (warm dry wind in California, FIRE-PROMOTING — the 2026 PYQ tests this).

Atmospheric Pressure + Winds (6 q · 50% HARD) is small but the densest-HARD subtopic. Pressure belts (at sea level, idealised): equatorial low (0°, intertropical convergence zone, rising air, rain belt); subtropical high (30°, descending air from Hadley cell, world's deserts), sub-polar low (60°, rising air at polar front, frontal storms), polar high (90°, descending cold air). Planetary winds: trade winds (30° → 0°, NE in N hemisphere, SE in S — Coriolis-deflected from high to low pressure); westerlies (30° → 60°, SW in N, NW in S); polar easterlies (90° → 60°). Jet streams: polar jet (~60°, between cold polar air + warm mid-latitude air), subtropical jet (~30°). Climate Classification (8 q · 38% HARD): Koeppen system uses temperature + precipitation. Major groups — A (tropical, no winter, all months >18°C), B (arid + semi-arid, evaporation > precipitation), C (temperate, mild winter), D (continental, cold winter), E (polar, all months <10°C). Sub-categories: Af (tropical rainforest), Aw (savanna), BWh (hot desert — Sahara), BSh (hot steppe), Cfa (humid subtropical — SE USA, NE China), Csa (Mediterranean — coast California, Med basin), Dfb (humid continental), ET (tundra), EF (ice cap).

The sub-skills

The rules and habits that decide whether you get a question right.

  • Atmospheric-layer altitude + lapse-rate identification

    Troposphere (0–12 km, lapse rate 6.5°C/km — temp DECREASES with altitude, weather here). Stratosphere (12–50 km, temp INCREASES with altitude due to ozone absorbing UV, ozone layer 20–30 km, smooth flight here). Mesosphere (50–80 km, temp decreases again, coldest layer, meteors burn here). Thermosphere (80–600 km, temp INCREASES to 2000°C, ionosphere + auroras 100–300 km). Exosphere (600+ km, satellites). Tropopause = troposphere-stratosphere boundary.

  • Tropical vs extratropical cyclone distinction

    TROPICAL: 5°–30° latitude (not at equator), warm ocean ≥27°C, moist air, NO fronts, has EYE (calm low-pressure center), winds rotate CCW (N) / CW (S), regionally named hurricane/typhoon/cyclone/willy-willy. EXTRATROPICAL: 30°–60° latitude (mid + high), driven by FRONTS (cold + warm air masses), larger area, NO warm core, NO distinct eye, jet-stream-driven, baroclinic.

  • Local wind ↔ region ↔ character matching

    Loo (N India, hot dry NW summer). Kalbaisakhi (WB-Assam, pre-monsoon thunderstorms). Chinook (Rockies leeward, warm dry, 'snow eater'). Foehn (Alps leeward, warm dry). Mistral (Rhône valley France, cold N). Sirocco (Sahara → S Europe, hot dry dust-laden). Harmattan (Sahel W Africa, dry dust). Santa Ana (S California, warm dry, fire-promoting). Bora (Adriatic, cold downslope). Berg (S Africa, hot dry).

  • Pressure-belt + trade-wind mechanism

    Pressure belts: equatorial low (0°), subtropical high (30°), sub-polar low (60°), polar high (90°). Wind flows high→low pressure but Coriolis deflects: trade winds (30°→0°) blow NE in N, SE in S. Westerlies (30°→60°) blow SW in N, NW in S. Polar easterlies (90°→60°). Jet streams: polar jet at ~60°, subtropical at ~30°, narrow fast westerly winds in upper troposphere.

  • Koeppen climate-zone identification

    A (tropical, all months >18°C) — Af rainforest, Am monsoon, Aw savanna. B (arid, evaporation > precipitation) — BWh hot desert (Sahara), BWk cold desert, BSh hot steppe, BSk cold steppe. C (temperate, mild winter) — Cfa humid subtropical, Csa Mediterranean, Cwa subtropical-monsoon (N India). D (continental, cold winter) — Dfa/Dfb humid continental, Dfc subarctic. E (polar) — ET tundra, EF ice cap. India: Cwa N, Aw central, BSh-BWh NW, Am Western Ghats.

2 worked examples from the bank

Real past-year questions illustrating the playbook. Click to reveal options + solution.

Example 1Climatology, Atmosphere and WeatherHARD
Consider the following statements about temperature inversion: I. This happens when normal lapse rate gets inverted. II. Winter nights with cloudy skies are conducive for temperature inversion. III. Polar areas experience inversion throughout the year. Which are correct?

[Q107 · Apr · 2026]

Example 2Climatology, Atmosphere and WeatherMODERATE
Consider the following statements regarding extratropical cyclones: I. They usually develop in the mid and high latitudes. II. They affect a much larger area as compared to tropical cyclone. III. They move from east to west. Which are correct?

[Q108 · Apr · 2026]

Traps to expect

Distractor shapes specific to this chapter. The page-wide Traps section covers the bank-level patterns.

  • Temperature inversion = normal lapse rate

    Normal lapse rate: temperature DECREASES with altitude in troposphere (~6.5°C/km). INVERSION: temperature INCREASES with altitude (opposite). Happens on winter nights (radiation cooling at surface), in valleys (cold air pools), and ahead of warm fronts. Causes fog, smog, poor air quality (pollutants trapped). The 2026 HARD PYQ tests inversion statements. Distractor calls inversion 'the normal lapse rate' or claims it doesn't form on winter nights.

  • Tropical cyclones form at equator

    Tropical cyclones do NOT form within ~5° of equator because Coriolis force ≈ 0 there, can't initiate the spin that creates a cyclonic system. They form 5°–30° latitude where warm ocean (≥27°C) + sufficient Coriolis coexist. Distractor says 'cyclones form at the equator' (wrong) or 'cyclones form anywhere over warm water' (wrong — needs Coriolis too). This is why hurricanes/typhoons start in tropical seas BUT not directly on equator.

  • Ozone layer in troposphere

    Ozone layer is in STRATOSPHERE (20–30 km altitude), NOT troposphere. Tropospheric ozone is a POLLUTANT (component of smog, harms lungs). Stratospheric ozone PROTECTS Earth by absorbing UV-B and UV-C. Distractor places ozone in troposphere or mesosphere. The lapse-rate clue: stratospheric ozone absorbs UV → heats the stratosphere → temperature INCREASES with altitude there.

  • Chinook is a cold wind

    Chinook is a WARM DRY wind blowing down the LEE (eastern) side of the Rocky Mountains. Called 'snow eater' because it can melt feet of snow in hours via temperature rises of 20–30°C. Distractor labels it cold (confusing with Mistral or Bora). Mnemonic: warm-dry downslope winds = Chinook (Rockies), Foehn (Alps), Berg (S Africa), Santa Ana (California). Cold downslope = Bora (Adriatic), Mistral (Rhône).

Drill every climatology, atmosphere and weather question

57 questions from the bank, scoped to 6 bundled subtopics.

Drill the 57 questions

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