CSS Geography Climatology Syllabus

Why do oceans have a smaller temperature range than landmasses?

Water heats and cools more slowly than land (higher specific heat, transparency, mixing, and evaporation), so maritime climates are moderate while continental climates are extreme.

Distinguish between the elements and the factors of climate.

Elements are the measurable conditions describing climate (temperature, pressure, wind, humidity, precipitation). Factors are the controls that influence those elements (latitude, altitude, continentality, ocean currents, winds, relief).

How does altitude affect temperature and pressure?

Both temperature and atmospheric pressure decrease with increasing altitude (temperature about 6.5°C per 1000 m; pressure roughly halves every ~5.5 km).

What instrument measures atmospheric pressure, and what is the standard sea-level pressure?

The barometer (mercury or aneroid); standard sea-level pressure is about 1013.25 millibars (760 mm of mercury).

Name the four major pressure belts of the world.

Equatorial low-pressure belt, Subtropical high-pressure belt (~30°N/S), Sub-polar low-pressure belt (~60°N/S), and Polar high-pressure belt (~90°N/S).

Why is the equatorial low-pressure belt also called the Doldrums?

Intense heating causes air to rise (convection), creating low pressure with calm, light, and variable winds — the belt of calms known as the Doldrums.

What are the 'Horse Latitudes' and where are they located?

The subtropical high-pressure belts around 30°N and 30°S, characterized by calm, descending air and light variable winds.

Distinguish between thermally induced and dynamically induced pressure belts.

Thermally induced belts result from heating/cooling of air (equatorial low, polar high), while dynamically induced belts result from Earth's rotation and air movement/subsidence (subtropical high, sub-polar low).

Name the three major planetary (prevailing) wind systems.

The Trade winds, the Westerlies, and the Polar easterlies.

From which pressure belts do the Trade winds blow, and in what direction in each hemisphere?

They blow from the subtropical highs (~30°) toward the equatorial low; they are northeast trades in the Northern Hemisphere and southeast trades in the Southern Hemisphere.

What is Ferrel's Law / the Coriolis effect's impact on wind direction?

Due to Earth's rotation, moving winds are deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Where do the Westerlies blow, and why are they called the 'Roaring Forties'?

They blow from the subtropical highs (~30°) toward the sub-polar lows (~60°), from the SW in the N. Hemisphere and NW in the S. Hemisphere; in the Southern Hemisphere their strength over open ocean earns the names Roaring Forties, Furious Fifties, and Shrieking Sixties.

State Buys Ballot's Law.

If you stand with your back to the wind in the Northern Hemisphere, low pressure lies to your left and high pressure to your right (reversed in the Southern Hemisphere).

What is a monsoon, and from which word is the term derived?

A monsoon is a seasonal reversal of wind direction (and associated rainfall) between summer and winter; the word derives from the Arabic 'mausim' meaning season.

Describe the summer (southwest) monsoon over the Indian subcontinent.

In summer the landmass heats, forming low pressure that draws moist Southwest winds from the Indian Ocean toward the land, bringing heavy rainfall (roughly June-September).

Describe the winter (northeast) monsoon over the Indian subcontinent.

In winter the land cools and develops high pressure, so dry Northeast winds blow from the land toward the sea, producing the dry season (and some rain on the southeast coast).

Besides differential heating of land and sea, what modern factor is used to explain the monsoon?

The seasonal migration of the Inter-Tropical Convergence Zone (ITCZ) and the shifting of the upper-air jet streams (subtropical and tropical easterly jet).

What is a local wind? Give two examples.

A local wind is a wind affecting a small area produced by local differences in temperature and pressure; examples include land/sea breezes, mountain/valley breezes, Chinook, Foehn, Loo, Mistral, and Sirocco.

Explain the difference between a sea breeze and a land breeze.

A sea breeze blows from cooler sea to warmer land during the day; a land breeze blows from cooler land to warmer sea at night.

What are the Foehn and Chinook winds, and what effect do they have?

They are warm, dry winds blowing down the leeward side of mountains (Foehn in the Alps, Chinook in the Rockies); they raise temperatures rapidly and melt snow.

Identify the local winds: Loo, Mistral, and Sirocco.

Loo is a hot, dry summer wind of northern India/Pakistan; Mistral is a cold, dry wind blowing down the Rhône valley to the Mediterranean; Sirocco is a hot, dusty wind from the Sahara toward southern Europe.

Define an air mass.

An air mass is a large body of air with fairly uniform temperature and humidity characteristics throughout, acquired from its source region.

How are air masses classified by source region?

By moisture: maritime (m, from oceans) or continental (c, from land); and by temperature/latitude: Arctic (A), Polar (P), Tropical (T), Equatorial (E) — e.g., mT (maritime tropical), cP (continental polar).

Define a front in meteorology.

A front is the boundary or transition zone separating two air masses of different temperature, humidity, and density.

What is a warm front and how does it produce precipitation?

A warm front is where an advancing warm air mass rises gently over a retreating cold mass; the gradual ascent produces widespread layered (stratiform) clouds and prolonged light rain.

What is a cold front and what weather does it bring?

A cold front is where an advancing cold air mass undercuts and forces warm air to rise steeply; this causes towering cumulonimbus clouds, heavy showers, thunderstorms, and a temperature drop.

What is an occluded front?

An occluded front forms when a faster-moving cold front overtakes a warm front, lifting the warm air completely off the ground; it often marks the dissipating stage of a depression.

List the main stages/processes of the hydrological (water) cycle.

Evaporation (and transpiration), condensation, precipitation, and runoff/infiltration that returns water to oceans — a continuous closed cycle driven by solar energy and gravity.

Define condensation and state the conditions needed for it.

Condensation is the change of water vapour into liquid (or solid) form; it requires the air to be cooled to its dew point (saturation) and the presence of hygroscopic condensation nuclei.

Name the major forms/types of condensation.

Dew, frost, fog, mist, and clouds (with frost being condensation directly into ice when the dew point is below 0°C).

Differentiate between fog and mist.

Both are clouds near the ground formed by condensation; fog reduces visibility to less than 1 km, while mist is thinner and allows visibility greater than 1 km.

Define precipitation and name its common forms.

Precipitation is the fall of moisture from the atmosphere to the Earth's surface in liquid or solid form; forms include rain, snow, sleet, hail, and drizzle.

Describe the three main types of rainfall by mechanism of uplift.

Convectional (heated air rises, common in equatorial regions/afternoons), Orographic/relief (air forced to rise over mountains, with a wet windward side and dry leeward rain shadow), and Cyclonic/frontal (warm and cold air masses meet along a front).