Water and carbon cycles Flashcards
What is a model
An idealised representation of reality
What is a system
A set of inter-related components or events working together
What does a system typically consist of
inputs, stores and outputs, with a series of flows or connections between them
What are the different types of systems
close
open
isolated
sub systems
What is an isolated system
there are no interactions with anything outside the system boundaries - there is no input or output of energy or matter
What is an open system
Both energy and matter transfer freely into and out of the system
What is a closed system
There is a transfer of energy into and beyond the system but no transfer of matter
What is a sub-system
A component of a larger system. The earth system has 5 sub systems, each of which is an open system with interrelationships between them.
What is dynamic equilibrium
Where there is a balance between inputs and outputs. For example, Wave currents remove and replace sand on a shoreline but the beach apparently stays the same
What are the 5 sub-systems of the earth
- Lithosphere
- Hydrosphere
- Biosphere
- Cryosphere
- Atmosphere
When does feedback occur
When a change in one part of the system causes a change in another part.
What are the 2 types of feedback called
Negative feedback and positive feedback
What is negative feedback
A feedback which keeps a system in its original condition
What is positive feedback
A feedback where there is a progressively greater change from the original condition of the system
What do positive feedback mechanisms do
amplify the change in inputs or outputs
What does it mean when positive feedback mechanisms amplify change to the inputs or outputs
Means the system responds by increasing the effects of the change, moving the system even further from it’s previous state
What do negative feedback mechanisms do
counteract the changes in the inputs and outputs
What happens when negative feedback mechanisms counteract change to the inputs or outputs
Means that the system responds by decreasing the effects of the change, keeping the system closer to it’s private state
What is an example of positive feedback
- Temperature rises
- Ice covering cold parts of earth melts due to higher temperatures
- Less ice cover means less of the sun’s energy is reflected
- Less of sun’s energy being reflected means more is absorbed by the earth
What is an example of negative feedback
- Large amounts of C02 emitted
- CO2 in atmosphere increases
- Extra C02 cause plants to increase growth
- Plants remove and store more CO2 from atmosphere
- Amount of CO2 in atmosphere reduces
What are the 4 vital cycles that affect the earths sub-systems
- The carbon cycle - The nitrogen cycle
- The water cycle - The oxygen cycle
What are both the carbon and water cycles under pressure from
- ) An increasing population
2. ) Climate change
How much of the earths fresh water is frozen in cryosphere
69%
How much of the earths freshwater is stored in water sealed underneath the lithosphere ( groundwater)
30%
How much of the earths freshwater is stored on the earths surfaces in lakes and rivers etc ( Liquid freshwater)
0.3%
How much of the earths fresh water is stored as water vapour in the atmosphere
0.04%
How much water is contained in the hydrosphere
1.4 sextillion litres of water
How much water within the lithosphere is fresh and what is the water that is not freshwater called
Less than 3% of 1.4 sextillion litres is freshwater and most of the rest is saline water (salty)
What are ways water must be more accessible for humans
physically and economically
When water condenses and freezes what must happen to it’s energy
It loses energy
When water boils or melts, what happens to it’s energy
gains energy
What is the latent heat of fusion
Melting - The substance changes from a solid to a liquid - extra energy needed
Freezing - The substance changes from a liquid to a solid - loss of energy
What is the latent heat of vaporisation
Vaporisation - The substance changes from a liquid into a vapour - extra energy needed
Condensation - The substance changes from a vapour into a liquid - loss of energy
What is the latent heat of sublimation
Sublimation - The substance has a 2 phase change ( in this case from ice to gas) - extra energy needed
Deposition - The substance has a 2 phase change and loses energy ( gas to ice in deposition)
What are the 4 types of water stores
- Atmospheric
- Cryospheric
- Terrestrial
- Oceanic
What is evaporation the process of
turning a liquid into a gas
How does evaporation occur
When energy from the sun hits the surface of the water/land and causes liquid to change from liquid to a gas
What do the rates of evaporation depend on
- Amount of solar energy
- Availability of water
- Humidity of the air - The more humid the air, the closer to saturation point the air is, so less evaporation will occur
- Temperature of the air - Warmer air can hold more water then cold air
What is relative humidity
The amount of water vapour in the air at any given temperature compared to how much the air could possibly hold that temperature.
What happens if the air has 100% relative humidity
Said to be saturated, therefore holds as much water vapour as it can give the temperature
What is absolute humidity
The mass of water vapour in an air mass measured in grams per cubic metre (g/m3)
True or False - Warmer air can hold more water vapour than colder air.
True
What is condensation
The conversion of a vapour or gas into a liquid
When does condensation occur
- When air is cooled
- When there is a fall in pressure
What happens if air cools or there is a fall in pressure
It is able to hold less water vapour
What is the dew point
The temperature in which water vapour in the air turns into liquid water
What are 3 ways air can cool by
- ) By conduction
- ) By uplift through the atmosphere caused by relief features, fronts or connective uplifts
- ) By advection
How does conduction cool air
The ground loses heat rapidly and this chills the air above, this can also result in frost, dew and mist.
How does advection cool air
Where warm moist air moves over a cooler surface
Why does cloud formation and condensation need ‘dirty’ air
as it is the pollen and the dust particles around which water droplets form
What happens when the air reaches saturation point or dew point
Water particles form around pollen or dust particles (condensation nuclei)
The condensation which is a direct cause of precipitation can occur when
- ) Air temperature is reduced to dew point
2. ) Volume of air increases as it rises and expands but there is no addition in heat (adiabatic cooling)
What is adiabatic cooling
Volume of air increases as it rises and expands but there is no addition in heat.
What 3 different reasons may the air be forced to rise, each resulting in precipitation
- Air is forced to rise over the hills and mountains = Orographic rainfall.
- Air masses of different temperatures and densities meet, the warm air rising over the cool sinking air = frontal rainfall
- Warm air rises from a hot surface on sunny day = convectional rainfall.
What is orographic rainfall
Air is forced to rise over the hills and mountains
What is frontal rainfall
Air masses of different temperatures and densities meet, the warm air rising over the cool sinking air
What is convectional rainfall
Warm air rises from a hot surface on a sunny day
What is the definition of a Cryospheric process
A process that affects the ice at any scale
What are 3 Cryospheric processes
- ) Accumulation
- ) Ablation
- ) Sublimation
What is accumulation
Inputs into a glacial system due to snowfall
What is ablation
Output of a glacial system due to melting
What is sublimation
Ice changing directly into water vapour
On a glacier mass balance, what happens if the accumulation and ablation levels equal out.
Mass balance becomes zero.
What happens when there is a positive balance on a glacier mass balance
accumulation> ablation
What happens when there is negative balance ion a glacier mass balance
accumulation
What happens when accumulation is greater then ablation
Leads to a growth in ice mass and the potential glacial advance down the valley
What happens when ablation is greater than ablation
Leads to a loss of ice mass and potential retreat of the glacier up-valley
What are the factors that determine how ice moves
The glacial mass balance
temperature and precipitation regime of the area
What does a global scale mean in terms of the carbon and water cycles
Water is present on earth as a liquid, ice or atmospheric moisture. It is cycled between these stores and a range of processes outlined above and summarised in the global water cycle
What are the three main inputs of the drainage basin system
- Precipitation
- Evapotranspiration
- Run-off
What is precipitation
May fall as rain, hail or sleet. The duration and intensity will impact processes within the system
What is Evapotranspiration
Combined loss of water through evaporation and transpiration by plants.
What is Run-off
The output of water from the drainage basin system as it moves across the land surface either as overland flow or channel flow.
What is a interception store
Vegetation cover intercepts the precipitation and a store may be held on leaves and branches. Density of vegetation will affect this. Tropical rainforest can intercept 58% of rainfall.
What is a surface store
This mainly occurs in built environment such as puddles. In natural environments, infiltration normally occurs more quickly then rainfall and there will only be surface puddles after very long periods of rainfall or on impacted surfaces of bare rock
What is a Soil water storage
Pore spaces between soil particles fill with air and water. The amount of pore space varies in different soils: clay 40-60% volume, sand 20-45% volume.
What is a groundwater storage
Water stored underground in permeable and porous rocks
What is a channel storage
The volume of water in a river channel
What is a vegetation storage
Vegetation cover intercepts the precipitation and a store may be held on leaves and branches. Density of vegetation will affect this. ( sometimes referred to as interception store.)
What are all the flows in a drainage basin system
- Percolation
- Stemflow
- Infiltration
- Overland flow
- Channel flow
- Throughfall
- Throughflow
- Groundwater flow
What is stemflow
Water flows down the stem of plants and trees.
What is infiltration
Water soaks into the soil. Rate = infiltration rate. The texture, structure and organic content of the soil affect infiltration rate . The rate normally declines during the early part of a storm.
What is overland flow
Rainfall flowing over the ground surface either because the soil is saturated or because the rainfall is exceeding the soil infiltration capacity.
What is channel flow
The flow of water in rivers
What is Through fall
Water moving from vegetation to the ground
What is throughflow
The lateral movement of water down a slope to a river channel. Slower than overland flow but the rate is increased by the root systems of vegetation.
What is groundwater flow
Downward and lateral movement of water within saturated rock. This is a very slow movement. Water bearing rocks are called aquifers.
What is the infiltration capacity
The maximum rate at which water can be absorbed by a given soil per unit area under given conditions.
What are some of the factors that affect how much water can be infiltrated by a soil.
- ) Soil type
- ) Soil coverage
- ) The flow supply ( How intense is the rain? Is there drainage?)
- ) The topography and morphology of the slopes
- ) How humid are the soils already
- ) Soil compaction due to rain drop impact and other effects.
What does soil type mean
The texture, structure, hydrodynamic characteristics. Examples of soil textures are: silty gravels, clay, sandy loam and clay roam, all of which have different infiltration rates.
What helps control the rate of interception
- The plant type and shape
- Plant density
- Plant structure in terms of size, flexibility, strength and pattern of branches.
- Plant community structure
- Precipitation intensity
- Precipitation duration
- Wind speed
- Type of precipitation- rain, snow or sleet.
What is the water balance
The long term balance between the inputs and the outputs in the drainage basin system
What is the equation used for the water balance
Precipitation = runoff + evapotranspiration+/- [Change in storage]
P = Q + E +/- [S]
What happens when precipitation exceeds evapotranspiration
Positive Water balance
What happens when evapotranspiration exceeds precipitation
Negative water balance
What is a drainage basin system
Is an area of land drained by a river and it’s tributaries. It’s boundary, or watershed, marked by ridges of high land beyond which rainfall will drain into a neighbouring drainage basin.
Is the drainage basin system an open or closed system
open -has inputs and outputs of both matter and energy.
What is a drainage basin composed of
Inputs - (precipitation)
Flow and Transfers - (throughfall, stemflow, infiltration, percolation, overland flow and groundwater flow.)
Outputs - to the sea or atmosphere - (evapotranspiration)
Where do the flows of water within a drainage basin system end up
In either the river - which then transfers the water by channel flow.
or
In groundwater stores
What is the water leaving the drainage basin through channel flow called
runoff
What is the measurement for river flow.
river discharge
What is river discharge
The volume of water passing a measurement, measured in cumecs and calculated by multiplying cross sectional area by velocity
What is a river regime
The annual variations in the amount of discharge in a river, in response to climatic factors and drainage basin characteristics
What is a river regime plotted on
A hydrograph
What is a hydrograph
A graph showing river discharge against time
What is a flood hydrograph
Plots changes in the discharge of a river in response to a rainfall or storm event
What are two words that can be used to describe flood hydrographs
Flashy and Subdued
What does flashy mean
Short lag time, high peak, steep rising and falling limbs
What does subdued mean
Long lag time, low peak, gently rising and falling limbs
What are some physical factors that can affect drainage basins and the shape of a flood hydrograph.
- ) drainage basin characteristics - affect lag time and peak discharge
- ) The amount of water already present in the drainage basin - affects lag time
- ) Rock type - affects lag time and peak discharge
- ) Soil type - affects lag time and peak discharge
- ) Vegetation - affects lag time and peak discharge
- ) Precipitation - affects peak discharge
- ) Temperature - affects lag time and peak discharge
How do drainage basins affect the shape of a hydrograph
Large drainage basins can catch more precipitation, so they have a higher peak discharge compared to smaller bases. But smaller bases generally
What are some of the ways vegetation can impact the shape of a hydrograph
- Slows rate water gets to rivers - increasing lag time, reducing peak.
- Leaves intercept water - delays process
- Some lost altogether by evaporation
- Forest deciduous - interception varies, being less apparent in winter when leaves are lost
- Trees will also use water for growth - reducing speed water gets to river - overland and throughflow reduced.
What are some examples of things carbon can be found in
- clothes
- Yourself
- Food
- Cosmetics and sanitary products used.
- Hydrocarbons - which power many common appliances used.
What are uses of carbon
- ) Diamond is used in jewellery and also in drills.
- ) Carbon is used in the iron and steel industries
- ) Graphite combined with clays form the ‘lead’ used in strong pencils
- ) Carbon fibre is finding many uses as a very strong, yet lightweight material. Used in tennis rackets, skis, fishing rods, aeroplanes etc.
- ) Graphite carbon in a powdered, cake form is used as charcoal for cooking, artwork and other uses.
- ) Charcoal pills are used in medicine in pill or powdered form to absorb toxins or poisons from the digestive system.
- ) Carbon is used for control rods in nuclear reactors.
What are the main important compounds of carbon
- ) Methane - CH4
- ) Carbon Dioxide - C02
- ) Hydrocarbons
- ) Calcium Carbonate - CaCO3
- ) Bio molecules in living things
