CAIE AS Geography: Core Physical & Human Units Flashcards

Comprehensive vocabulary flashcards covering Hydrology, Atmosphere/Weather, Rocks/Weathering, and Population based on CAIE AS Geography core units.

Interception

The process where rainfall is caught by vegetation before reaching the soil.

Storm hydrograph rising limb

The portion of a hydrograph where discharge increases; its steepness is heightened by urbanization, steep slopes, or impermeable rock.

Throughfall

Rainfall that passes through the vegetation canopy to reach the ground.

River levées

Embankments formed by the deposition of coarse sediment during river flooding.

Hjulström curve

A graph showing that higher velocity is required for the erosion of sediment than for its deposition.

Flashy hydrograph

A hydrograph characterized by a short lag time and a steep rising limb.

Infiltration rate

The speed at which water enters the soil, which decreases when the soil surface becomes saturated.

Rejuvenation

A process occurring when a river's base level falls due to sea level drop or land uplift, increasing the river's erosive energy.

Braiding

A river channel pattern associated with high, variable discharge and a coarse bedload.

Bankfull discharge

The channel capacity at which the river is at a common flood stage, representing its maximum volume before overflowing.

Stemflow

The movement of intercepted water down the stems or trunks of plants.

Overland flow

Surface runoff triggered by either saturation excess or Hortonian flow.

Delta

A landform created by the reduction of river velocity and subsequent sediment deposition at the river mouth.

Lag time

The interval between peak rainfall and peak discharge; it is shortest in urban basins equipped with sewers.

River cliff

A steep bank formed on the outer concave bank of a meander.

Depression

A low-pressure weather system characterized by warm fronts, cold fronts, and occluded fronts.

Urban heat island

A localized climate phenomenon caused by concrete absorbing heat in cities, making them warmer than rural areas.

Köppen classification Aw

A climate category representing tropical wet/dry savanna.

Convectional rain

Precipitation resulting from intense surface heating and subsequent air rise.

Beaufort scale

A standardized scale used to measure wind speed.

Anticyclone

A high-pressure weather system which, in summer, results in clear skies and air subsidence.

Dew point

The specific temperature at which air becomes saturated and condensation begins.

Frontal fog

A form of fog created when warm air moves over a cold surface.

Microclimate

Small-scale climate variations, such as the difference between an urban canyon and a park.

Tropical storm requirements

Requires the Coriolis effect to be greater than $5^\circ\text{N}$, and Sea Surface Temperatures (SST) to be above $27^\circ\text{C}$.

Anabatic winds

Upslope winds caused by the heating of mountain slopes during the daytime.

Precipitation maximum

The location receiving the most rainfall, typically found on the windward coast of landmasses.

Insolation

Incoming solar radiation, which is reduced by clouds, latitude, and pollution.

Occluded front

A weather feature formed when a cold front overtakes a warm front, forcing the warm air to rise.

Chinook effect

Also known as the Föhn effect; it involves the warming of air as it descends the leeward side of mountains.

Mechanical weathering

The physical disintegration of rock without chemical change, such as freeze-thaw or exfoliation.

Plate divergence

The moving apart of tectonic plates, leading to the formation of mid-ocean ridges.

Biological weathering

Weathering caused by living things, such as plant roots growing into cracks or animal burrowing.

Salt crystallisation

A type of mechanical weathering common in arid coasts and deserts.

Subduction

The tectonic process occurring at destructive plate boundaries where one plate is forced beneath another.

Onion-skin weathering

Also known as exfoliation; the peeling of rock layers due to intense daily heating and cooling.

Carbonation

A chemical weathering process specifically involving the dissolution of limestone.

Conservative margins

Tectonic boundaries defined by transform faults where plates slide past each other, such as the San Andreas Fault.

Hydrolysis

A chemical weathering process that breaks down feldspar into clay.

Mass movement

The downslope movement of rock and soil under gravity; rockfall is the fastest category.

Demographic Transition Model Stage 2

A stage characterized by a high Crude Birth Rate (CBR) and a falling Crude Death Rate (CDR).

Natural increase

The rate of population growth calculated by subtracting the Crude Death Rate (CDR) from the Crude Birth Rate (CBR).

Pro-natalist policy

A government strategy to increase birth rates, exemplified by Romania's Decree $770$.

Dependency ratio

A measure that is high when a large percentage of the population is under $15$ or over $65$ years of age.

Population momentum

The tendency for a population to continue growing despite falling fertility rates because of a large youthful cohort.

Anti-natalist policy

A government strategy to reduce birth rates; historical examples include India's forced sterilisation.

Epidemiological transition

A shift in the pattern of disease from infectious diseases to degenerative diseases as a country develops.

Malthus

A theorist who predicted that population growth would eventually outpace the arithmetic growth of food supply, leading to famine.

DTM Stage 5

A stage of the Demographic Transition Model characterized by natural decrease, where birth rates fall below death rates.

Typhoon Haiyan and Hurricane Katrina comparison

LDC storms like Haiyan ($6000$ deaths) often have higher death tolls, while MDC storms like Katrina ($100\text{bn}$) cause higher economic damage.