AQA A-Level Geography - Water and Carbon

Precipitation

water that falls from clouds and reaches Earth's surface as rain, snow, sleet, or hail.

Evapotranspiration

The evaporation of water from soil plus the transpiration of water from plants.

Runoff

Water that moves across the land surface and into streams and rivers

Interception storage

precipitation falls on the vegetation surfaces (canopy) or human cover. temporarily stored. Intercepted water either evaporated directly to the atmosphere, absorbed by the canopy surfaces or ultimately transmitted to the ground surface.

Tropical rainforests intercept 58% rainfall

Surface storage

The total volume of water held on the Earth's surface in lakes, ponds and puddles.

Soil water storage

Water stored in the soil - clay 40-60%, sand 20-45%

Groundwater storage

The storage of water underground in permeable rock strata

Channel storage

Water held in a river or stream channel

Vegetation storage

Any moisture taken up by vegetation and held within plants

Stemflow

the flow of intercepted water down the trunk or stem of a plant

Infiltration

the process by which water on the ground surface enters the soil

Overland flow

water flowing across the soil surface on a hillslope, usually resulting from precipitation falling faster than the ground can absorb it

Channel flow

The flow of water in a river

Throughfall

Water that reaches the ground either directly or after being intercepted by vegetation.

Throughflow

Water flowing through the soil layer parallel to the surface

Percolation

The downward movement of water through soil and rock due to gravity.

Ground water flow

water running underground

positive water balance

precipitation exceeds evapotranspiration

negative water balance

Evapotranspiration exceeds precipitation

Q + E + (S) = P

runoff + evapotranspiration + change in storage = precipitation

Relief rainfall

caused by uplifting and cooling of moist air over mountains

Frontal rainfall

When a warm air mass meets a cold air mass the warm air rises

Convectional rainfall

Precipitation formed by rising currents of warm, moist air

accumulation

glacial system inputs due to snowfall

ablation

output of glacial system due to melting

Sublimation

solid to gas

Condensation

Gas to liquid

latent heat

the heat required to convert a solid into a liquid or vapor, or a liquid into a vapor, without change of temperature.

Evaporation

Liquid to gas

closed system

no energy or matter is transferred into + beyond system boundary - global

open system

matter and energy transferred from system across boundary into environment - ecosystems

isolated system

A system that can exchange neither energy nor matter with its surroundings.

dynamic equilibrium

balance between inputs and outputs

positive feedback

Feedback that tends to magnify a process or increase its output - negative effect

negative feedback

positive environmental effects

example of negative feedback

increased surface temp, increased evaporation, increased cloud cover, decreased radiation = cooling

amount of water on earth

71% of Earth is water

amount of available fresh water

3%

amount of accessible fresh water

1% = shortages and exploitation

amount of groundwater storage

20%

amount of ice cap and glacier storage

79%

atmosphere

A thin layer of gases surrounding Earth held by gravity

Lithosphere

the rigid outer part of the earth, consisting of the crust and upper mantle.

Biosphere

Consists of all life on Earth and all parts of the Earth in which life exists, including land, water, and the atmosphere.

Hydrosphere

All the water at and near the surface of the earth, 97% of which is in oceans

Cryosphere

A term referring to all water that is temporarily frozen in polar ice caps, snow, permafrost, and glaciers

factors affecting water transfer

relief, geology, vegetation, weather, urbanisation

Water stores

oceans, atmosphere, terrestrial, cryosphere

model

idealised representation of reality

system

A group of interacting, interrelated, or interdependent elements or parts that function together as a whole to accomplish a goal.

Transpiration

Evaporation of water from the leaves of a plant

factors affecting evapotranspiration

temperature, wind, humidity, climate - hrs of sunshine

condensation nuclei

Microscopic particles on which water vapor condenses to form cloud droplets.

dew point

the temperature at which the water vapor in the air becomes saturated and condensation begins

Aquifer

a body of permeable rock that can contain or transmit groundwater.

Milankovitch cycles

Changes in the shape earth's orbit and tilt that cause glacial periods and interglacial periods.

Little Ice Age

A century-long period of cool climate that began in the 1590s. Its ill effects on agriculture in northern Europe were notable.

Soil moisture surplus

the period when soil is saturated and water cannot enter, and so flows over the surface

Soil moisture deficit

the degree to which soil moisture falls below field capacity

soil moisture utilisation

The extraction of soil moisture by plants for their needs; efficiency of withdrawal decreases as the soil-moisture storage is reduced.

Soil moisture recharge

when precipitation is greater than potential evapotranspiration and the soil moisture is not to capacity, moisture will be added to the soil

how ph level affects marine systems

breakdown of ecosystems - mutations, extinction, biodiversity loss, slow calcification rates

carbonic acid

a very weak acid formed in solution when carbon dioxide dissolves in water.

25% increase in acidity over 200yrs

amount of water stored in atmosphere

0.001%

ice sheet example

Greenland ice sheet

alpine glacier example

mer de glace, france

permafrost example

Alaska north slope

ice cap example

Iceland ice cap

sea ice example

ross ice shelf

clouds

A collection of water droplets or ice crystals in the atmosphere.

drainage basin

the area from which a single stream or river and its tributaries drains all of the water

watershed

The land area that supplies water to a river system.

average ice age occurs

every 100,000 years

water balance

amount of water in a cycle affected by inputs and outputs

winter months - soil water

refilling/replenishing soil moisture due to increased precipitation

summer months - soil water

using soil moisture, runs out towards end of season (deficit)

river regime

The variation (seasonal pattern) in river discharge over the course of a year.

discharge

the quantity of water in a stream that passes a given point in a period of time

Flood hydrograph

graph of stream discharge over a time period for a specific place, lag time, peak, rising limb, falling limb, base flow

lag time

Time between peak rainfall and peak discharge

rising limb

The increase in river discharge as rainwater flows into the river - shows how quickly river responds to a 'storm'

Peak discharge

The greatest volume of water that flows in the river at a given time.

Falling limb

The decrease in river discharge as the river returns to its normal level

Bos castle

confluence of 3 rivers, vegetation (interception), urbanised (increased run off), extremely steep relief

capillary action

the attraction of the surface of a liquid to the surface of a solid

soil porosity

pores or spaces in the soil. The greater pores or spaces, the greater the water holding ability.

factors affecting river regime

geology, vegetation, urbanisation, river management, farming practices

physical factors affecting storm hydrograph

circular drainage basin, higher drainage density, thick vegetation, intense precipitation, impermeable surface

human factors affecting storm hydrograph

urbanisation, afforestation, deforestation, ploughing

deforestation affect water cycle

reduces moisture pulses, forest = low pressure.

rain dependent of forests - reduced transpiration.

increased co2 with burning of trees = disrupt cloud convection.

abundance of water + loss through transpiration

irrigation

The process of supplying water to areas of land to make them suitable for growing crops.

soil leaching

loss of soil nutrients due to rain and irrigation (coarse-textures soils more vulnerable)

saltwater intrusion

movement of saltwater into an aquifer, which may cause contamination.

Water abstraction

The extraction of water from rivers or groundwater aquifers

e.g. Central USA use 53 billion gallons water day from aquifers - 174,000miles2

land drainage

excess water removed e.g. Somerset levels - water table lowered

Flashy hydrograph

Short lag time and high peak discharge

Subdued hydrograph

Long lag time and low peak discharge

base flow

Normal discharge of the river

global scale

water present on earth as liquid, ice, atmospheric moisture, cycled between stores on global scale

circulation of water between continents and ocean

circulation more rapid in tropical landmasses - most water in Pacific circulates in Pacific