Water and Carbon Flashcards
inputs definition
when matter or energy is added to a system
outputs definition
when matter or energy leaves the system
stores/components definition
where matter of energy builds up
flows/transfers definition
when matter or energy more from one store to another
boundaries definition
the limits of the system
open systems
both energy and matter can enter and leave an open system, there are inputs and outputs of both
e.g. drainage basins, energy from the sun enters and leaves the system, water is input as precipitation and output as river discharge into the sea
closed systems
matter cant enter or leave, can only cycle between stores
energy can enter or leave
e.g. carbon cycle, energy is input from the sun through photosynthesis and output through respiration but the amount of carbon on earth stays the same because there are no inputs or outputs of matter
equilibrium
when the inputs and outputs of a system are balanced
dynamic equilibrium
lots of small variations between inputs and outputs in a system but they are small so they remain balanced on average
large long term changes to the balance of inputs and outputs can cause a new system to change and establish a new dynamic equilibrium
positive feedback
amplifies the change in inputs or outputs
the system responds by increasing the change, moving the system even further from its previous state
e.g.: temp rise, ice melts, less ice=less of the sun’s energy is reflected, more energy absorbed by earth…repeat
negative feedback
counteracts the change in inputs or outputs
the system responds by decreasing the effects of the change, keeping the system closer to its previous state
e.g. co2 emitted, co2 in the atmosphere increases, causes plant growth to increase, plants remove and store co2,, co2 in atmosphere reduces
subsystems
cryosphere
all the parts of the earth system where its cold enough for water to freeze e.g. glacial landscapes
subsystems
lithosphere
outermost part of the earth, includes crust and upper mantle
subsystems
biosphere
part of the earth’s systems where living things are found, includes all living parts of the earth including plants, animals, birds, fungi, insects, bacteria etc
subsystems
hydrosphere
all of the water on earth
liquid, solid or gas
saline or fresh
subsystems
atmosphere
the layer of gas between earth’s surface and space, held in place by gravity
subsystems definition
the earth system broken down
all interlinked
matter and energy move between subsystems, the output of one is the input of the next etc: cascading system
changes that occur in one subsystem can effect what happens in others
percentage of saline water
97%
freshwater distribution
only 3% of earth's water is freshwater 69% frozen in cryosphere 30% groundwater 0.3% liquid freshwater 0.04% stored as water vapour in the atmosphere
water cycle
stores
cryosphere: glaciers, ice caps
groundwater and lithosphere
liquid water: oceans, lakes, rivers
atmosphere: clouds, water vapour
the magnitude of stores
the amount of water present in each store varies over a range of scales from local, e.g. hillslope to drainage basin to global
processes driving change in the magnitude of stores
evaporation
occurs when liquid changes to gas, gains energy from solar radiation
increases the amount of water in the atmosphere
magnitude of evaporation varies by location and season:
lots of solar radiation, large supply of water and warm dry air then evaporation is high
not much solar radiation, little water and cool air that is already nearly saturated then evaporation will be low
processes driving change in the magnitude of stores
condensation
when water vapour becomes a liquid, loses energy to surroundings
happens when air containing water vapour cools to dew point, e.g. at night
water droplets can stay in the atmosphere or flow to other subsystems which would decrease the amount of water stored in the atmosphere
magnitude of condensation flow depends on amount of water vapour in atmosphere and temperature:
lots of water + rapid drop in temp = high condensation
processes driving change in the magnitude of stores
cloud formation and precipitation
precipitation is the main flow of water from atmosphere to ground
clouds form when warm air cools down, causing water vapour in it to condense into water droplets which gather as clouds and when the drops get big enough they fall as precipitation
water droplets caused by condensation are too small to form clouds on their own, for clouds to form there has to be tiny particles of other substances e.g. dust or soot that act as cloud condensation nuclei, they give water a surface to condense on. this encourages clouds to form rather than allowing the moist air to disperse
processes driving change in the magnitude of stores
cryospheric processes
accumulation (input) and ablation (output)
change the amount of water stored in the cryosphere
the balance of accumulation and ablation varies with temperature
during periods of global cold inputs into the cryosphere are greater than outputs, water is transferred to it as snow and less water is transferred away due to melting, during warmer global temperatures the magnitude of the cryosphere reduces as losses due to melting are larger than inputs of snow
variations in cryospheric processes happen over different timescales, there are the changes in global temperature that happen over thousands of years but they can also happen over shorter timescales such as annual temperature fluctuations when more snow falls in winter than summer
drainage basins as natural systems
open, local hydrological cycles
a drainage basin is the area surrounding the river where the rain falling on the land flows into that river, also known as the rivers catchment
the boundary of the drainage basin is the watershed, any precipitation falling beyond this point enters a different drainage basin
water comes into the system as precipitation and leaves via evaporation, transpiration and river discharge
drainage basins
inputs
precipitation, includes all the ways moisture comes out of the atmosphere
rain, snow, hail, dew and frost
drainage basins
storage
1) interception: when precipitation lands on vegetation or other structures before it reaches the soil. creates a significant store of water in wooded areas, only temporary because the water collected may evaporate quickly or fall from the leaves as throughfall
2) vegetation storage: water taken up by plants, all the water contained in plants at any one time
3) surface storage: incldues water in puddles, ponds and lakes
4) soil storage: includes moisture in the soil
5) groundwater storage: water stored in the ground either in soil or rocks. the water table is the top surface of the zone of saturation. porus rocks that hold water are called aquifers
6) channel storage: water held in a river or stream channel
drainage basins
flows
1) infiltration: water soaking into the soil, infiltration rates are influenced by soil type, soil structure, and how much water is already in the soul
2) overland flow: water flowing over the land, happens because water is falling faster than infiltration
3) throughfall: water dripping from one leaf to another
4) stemflow: water running down a plant stem or tree trunk
5) throughflow: water moving slowly downhill through the soil, faster through ‘pipes’ (cracks in the soil or animal burrows)
6) percolation: water seeping down through soil into the water table
7) groundwater flow: water flowing slowly below the water table through permeable rock, permeable=faster, e.g. limestone
8) baseflow: groundwater flow that feeds into rivers through river banks and river beds
9) interflow: water flowing downhill through permeable rock above the water table
10) channel flow: water flowing in the river or stream itself (river discharge)
drainage basins
outputs
1) evaporation: water turning into water vapour
2) transpiration: evaporation from within leaves, plants and trees take up water through their roots and transport it to their leaves where it evaporates into the atmosphere
3) evapotranspiration: the process of evaporation and transpiration together
4) river discharge/river flow