Cambridge International AS and A Level Geography Revision Flashcards

Flashcards covering the vocabulary and key concepts of Hydrology, Atmosphere, Rock Weathering, Population, Migration, and Settlement Dynamics from the AS and A Level Geography Revision Guide.

Drainage basin

A natural system with inputs, flows and stores of water and sediment, referring to the area drained by a river and its tributaries.

Hydrology

The study of water as it moves on, and under and through the Earth's surface.

Precipitation

The conversion and transfer of moisture in the atmosphere to the land, including rainfall, snow, frost, hail and dew.

Interception

The precipitation that is collected and stored by vegetation.

Evapotranspiration

The combined loss of water to the atmosphere through transpiration and evaporation.

Infiltration capacity

The maximum rate at which rain can be absorbed by a soil in a given condition.

Runoff

Water that flows over the land's surface.

Water table

The upper layer of the phreatic zone (permanently saturated zone within solid rocks and sediments).

Baseflow

The part of a river's discharge that is provided by groundwater seeping into the bed of a river.

River regime

The annual variation in the flow of a river.

Storm hydrograph

A graph showing the variation in the flow of a river for a short period, typically between $1$ and $7$ days.

Lag time

The time between the peak of the storm and the maximum flow in the river.

Hjulstrom curves

Graphs that show what work a river will do (erosion, transport, or deposition) based on its velocity and the size of material present.

Hydraulic radius

A measure of a stream's efficiency calculated by dividing the cross-sectional area by the wetted perimeter.

Levées

Embankments formed when a river repeats its bank-bursting over a long period, depositing coarse material near the channel edge.

Insolation

Incoming solar radiation (heat energy from the Sun) that reaches the Earth's surface.

Albedo

The proportion of energy that is reflected back to the atmosphere.

Sensible heat transfer

The movement of parcels of air into and out from the area being studied, such as air warmed by the surface beginning to rise (convection).

Latent heat transfer

Energy used to turn liquid water into water vapour (evaporation) or released when water vapour becomes a liquid (condensation).

Temperature inversion

A relative increase in temperature with height in the lower part of the atmosphere, often acting as a lid on pollutants.

Inter-tropical convergence zone (ITCZ)

A band a few hundred kilometres wide in which winds from the tropics blow inwards, converge and rise, forming low-pressure.

Monsoon

A term meaning 'reverse,' referring to a seasonal reversal of wind direction.

Environmental lapse rate (ELR)

The actual temperature decline with height, averaging approximately $6\,^{\circ}C/km$.

Dry adiabatic lapse rate (DALR)

The rate at which dry (unsaturated) air cools or warms when rising or sinking, approximately $10\,^{\circ}C/km$.

Saturated adiabatic lapse rate (SALR)

The rate at which rising air in which condensation is occurring cools, averaging approximately $5\,^{\circ}C/km$.

Greenhouse effect

The process where gases like $CO_2$ and methane trap outgoing long-wave radiation, raising the temperature of the lower atmosphere.

Stern Report (2006)

A report by Sir Nicholas Stern analyzing the financial implications of climate change on world economies.

Urban heat island

The phenomenon where urban areas are warmer than surrounding rural areas, especially at dawn during anticyclonic conditions.

Lithosphere

The upper surface layer of the Earth, including the crust and upper mantle, approximately $70\,km$ deep.

Sea-floor spreading

The process at constructive margins where ocean floors grow as plates move apart.

Paleomagnetism

The study of magnetic grains in lava that acquire the direction of the Earth's magnetic field at the time of cooling.

Weathering

The decomposition and disintegration of rocks in situ.

Freeze-thaw

Physical weathering occurring when water in joints and cracks expands by about $10\%$ upon freezing at $0\,^{\circ}C$.

Tor

An isolated mass of rock, often granite, left standing on a hilltop after surrounding rock has been removed.

Mass movements

Large-scale movements of the Earth's surface not accompanied by a moving agent such as a river or glacier.

Crude birth rate

The number of live births per $1000$ population in a given year.

Total fertility rate

The average number of children born alive to a woman during her lifetime if she conforms to age-specific fertility rates.

Replacement-level fertility

The level at which a generation has just enough children to replace themselves, usually a total fertility rate of $2.1$.

Dependency ratio

The ratio of the number of people under $15$ and over $64$ years to those in the economically active group ($15-64$).

Demographic transition

The historical shift of birth and death rates from high to low levels in a population.

Ecological footprint

A sustainability indicator expressing the relationship between population and the natural environment's resources.

Migration

The movement of people across a specified boundary to establish a new permanent place of residence for more than $1$ year.

Remittance

Money sent home to families by migrants working elsewhere.

Stepped migration

A process where a rural migrant heads to a small town first, then moves up the urban hierarchy to larger settlements over time.

Counterurbanisation

The process of population decentralisation as people move from large urban areas to smaller settlements and rural areas.

Global (world) city

A city judged to be an important nodal point in the global economic system, classified into categories like Alpha ++.

Bid-rent theory

The theory that land users compete for location based on accessibility, with the highest price paid for central locations.

Favelas

A Brazilian term for informal, shanty-type settlements generally involving illegal occupation of land.

Hukou system

China's population register that identifies people as either 'urban' or 'rural' to control internal migration.

In situ urbanisation

The transformation of rural settlements into urban entities with very little population movement.