AS Geography paper 1 (T1-2)

Hydograph

shows how the rivers discharge changes overtime in relation to percipitaion

Lag time

the time gap in between peak rainfall and peak discharge in a hydograph

Rising limb

the increase of the rivers discharge on a hydrograph

Falling limb

the decrease of the rivers discharge on a hydrograph

Errosion

the wearing away of mattirial

Load

the sedement that the river is carrying

Cavitation

when the pressure within the river decreases bubbles form and explode with errodes the surounding rock

River discharge

how much water the river is carrying in it’s channel at a given time

Bank full capacity

the time when the river is at it's fullest before flooding

Entainment velocity

the velocity needed to pick up the load in the river

Wetted perimeter

the part of the river channel in contact with waster

Dynamic equilibruim

the state of balamce within the river where it's energy is balanced against the sedement size and load

Turbulance

irregular movements of water in the rivers course

Talweg

the deepest part of a rivers path that has the highest velocity which hits the outside bend to the inside end of a meander

Subcriticle flow

water moves slowly leading to distubances upstream

Supercriticle flow

water moves rapidly in shallow areas

Criticle velocity

the velocity that seperates supercriticle and subcriticle velocity

Hydraulic action

air forces itself into cracks which creates pressure and widens the faults in the rock

Abrasion

wearing down of the river bed through the process of corrosion

Solution (errosion)

the removal of chemical ions where the water breaks down rock

Solution (transport)

desolved sedement is moved within the river

Saltation

small sedement is bounced along the river bed

Attrition

when the sedement hits each other causing the load to become smaller and rounder

Suspention

finer sedement us carried in rapids of the river

Traction

larger sedement rolls on the rivers bed

Recurance inteval

the avarage time between events

Abstraction

the process if removing water from bodies of water

Short term inputs

imediate effects of a hazard from hous to weeks

Long term hazards

occurs months or years after a hazard

Hazard vunrebility

the degree to which people pleases or infustructure is likely to be effected by a hazard

Hard engineering

using man made solutions to manage the river

Soft engineering

working alongside the rivers natural processes

Laminar flow

when the water in the river moves in parrallel lines that dont tend to mix

Turbulant flow

water moves irregularly due to high velocity and rough beds

Helicoidal flow

spiral like flow which tranports sedement from the outside to inside bend

Climate change

the long term shift in weather patterns

Quanternary period

current geological period 2.6 million years ago to current day

Ice cores

drilling into ice to schow the concentration of gases during cerian periods

Tree rings

one ring forms yealy, thicker rings show that it is wamer and wetter

Global warming potential

a measure og how much heat a greenhouse gas traps in the atmosphere compaired to carbon dioxide

Rising sea level

has risen 10-20 cm in 100 years

Melting ice caps

in 30 years the artic has thined in half, cauing a decreased albedo

volcanic activity

large erruptions release ash and sulphur dioxe which forms a reflective layer cooling the earth

Solar output

sunspots emmit more energy towars the earth within a 11 year cycle, leads to higher tempretures

Orbital changes

the orbit shifts slowly, eliptical obits lead receive less solar energy leading to cooling

Atmosphere

layer of transparent gases surrounding the earth

Weather

specific climatic condtions in a certain place at a guven time

Climate

the expected weather conditions

Energy budget

the amound of energy entering and leaving the sysem

Ocean current

large scale movements of water across the ocean

Diurnal energy budget

how energy moved in an out of a specific area over a day

Phase changes

chages in state of matter

Latent heat

energy absorbed or released during phase chnages

Exothermal reaction

loss of heat to thr surroundings

endothermal reactions

gain of heat to the surroundings

Evaporation

water to water vapour

Saturation (in the atmosphere)

the atmosphere holding as much water vapour as it can

Vapour pressure

the pressure exerted by the water vapour in the air

Condensation

water vapour to water

Dew point tempreture

the tempreture whereby the atmosphere can not hold water vapour

Condensation nuclei

particles suspened in the atmosphere where condensation occurs

Radient cooling

loss of earths heat by radiation allowing tempretues to reach dew point

Contact cooling

warmer air mover over a cold ocean cooling the air forming low lying clouds

Adiabatic cooling

air rises expands then cools as the pressure decreases in the atmosphere forming clouds

Frezzing

water to ice

Melting

ice to water

Sublimation

direct change from solid to gas without turing into a liquid

Deposision

water vapour directly changing into ice releasing latient heat

Percipition

all forms of moisture moving from the atmosphere to earth

Postive feedback loop

inicial changes causes effects that amplify the original change

Incoming shortwave radiation

energy from the sun to the earth

Outgoing longwave radiation

previously absorbed shortwave ratiation that is emmited to space

Albedo

the ratio of shortwave radiation reflected by a surface

Back radiation

longwave radiation trapped in the atmosphere making nights warmer

Sensible heat transfer

moves thoguht convection currents during the day as the earth heayts up and transfers energy to the atmosphere

Convectional rainfall

As water is heated it evaporates into water vapour which rises cools and condences forming clouds leading to rainfall

Frontal rainfall

when a warm and cold front meet the warm front is forced upwards a=by the more dence cold front that undercuts the warm front in ceasing the rate of cooling and condesation

Oragraphic rainfall

air is forced to rise upwards as it meets the side of a slope where it cools and condences forming clouds and heavy rainfall as the air sinks it warms up causing to minial rainfall on the leward side