Natural Systems & The Water Cycle Flashcards
Pages 2 - 5 of Revison Guide Natural systems and The Water Cycle
What are systems made of?
Stores, flows, boundaries, inputs and outputs
What are inputs?
When matter or energy is added to the system
What are outputs?
When matter or energy leaves the system
What are stores/components?
Where matter. or energy builds up
What are flows/transfers?
When matter or energy moves from one side to another
What are boundaries?
The limits of a system
Systems are either …
Open or closed
What is an Open System?
Both energy and matter can enter and leave - there are inputs and outputs
What is an example of an open system
Drainage basins are open as energy from the sun enters and leaves. Water is an input as precipitation but an output as river discharge to the sea
What is a closed system?
Matter can’t enter or leave - it can only cycle between stores. Energy can enter and leave - it can be an input or output
What is an example of a closed system?
Carbon cycle has energy as an input from photosynthesis and output by respiration, but the amount of carbon on earth remains because there are no inputs or outputs matter
What happens if the inputs and outputs are balanced?
The system is in equalibrium
What does equilibrium mean ?
Flows and processes happen but there are no overall changes to the system
What happens if there is large long term changes?
The balance of inputs and outputs cause a system to change and establish a new dynamic equilibrium
What does the long term change trigger?
Positive or negative feedback
What is positive feedback?
Amplifies the changes in inputs and outputs. Meaning the system responds by increasing the effects of change, moving the system away from dynamic equilibrium
What is Negative Feedback”?
Counteract the changes in inputs and outputs. Meaning the system responds by decreasing the effects of the change keeping the system closer to it’s previous state
What kind of system is the earth?
Closed
Why is the Earth a closed system?
Energy is input from the sun and output to space - Matter. isn’t inputed or outputted
What the Earth’s system broken down into?
Subsections
What are the 5 subsystems
1) Cyrosphere
2) Lithosphere
3) Biosphere
4) Hydrosphere
5) Atmosphere
What is the cryoshere?
includes all the earths systems were its cold enough for water to freeze eg - Glacial Landscapes
What is the Lithoshpere?
The outermost part of the earth. Includes the crust and upper parts of the mantle
What is the Biosphere?
Part of the Earths systems where living things are found. Includes all living parts of the earth -Plants, animals, bacteria
What is the Hydrosphere?
Includes all water on the earth.May be in liquid form (Lakes and rivers), Solid. form (Ice stored in cryosphere) or gas (Water Vapour in atmosphere). Can be saline or fresh
What is the Atmosphere?
The layer of gas between the earths surface and space, held in place by gravity
How do these subsections keep the earths systems running as normal?
They are all interlinked by cycles and processes
What does matter and energy do?
Move between subsystems - output of 1 cycle is the input of another, that output is the input of the next
What does it mean for the earth because of this movement?
It is cascading
How many litres of water does the hydrosphere contain?
1.4 sextillion litres
What % is freshwater?
Less than 3%
What is the rest of the water?
Saline in the oceans
Of the freshwater how much is frozen in the cryosphere?
69%
Of the freshwater how much is groundwater?
30%
What is groundwater?
Water stored underground ink the lithosphere
Of the freshwater how much is liquid freshwater on the earths surface in lakes and rivers?
0.3%
Of the freshwater how much is stored as water vapour in the atmosphere?
0.04%
What should water be?
Physically and economically accessible for humans
Why is only a small amount of water used by humans?
Because groundwater is hard to access and not cost effective to extract
When does changing state require It to gain energy from the sun?
Melting, sublimation and evaporation.
When does changing state require It to lose energy?
Freezing, Condensation and Deposition
What is the global hydrological cycle?
water is continuously cycled between different stores
What type of system is the hydrological cycle
Closed
Why is the hydrological cycle closed?
There’s no inputs or outputs of water. Energy is inputed from sun and lost to space
What varies from local to global scales about the WC?
The amount of water present in each store
What does the magnitude depend upon?
The amount of water flowing between them
What do different flows occur at?
A ranges spatial and temporal scales
When does evaporation occur?
Liquid water changes to a gas becoming water vapour
How does evaporation gain energy?
Solar Radiation
What does evaporation increase?
The amount of water stored in the atmosphere
What does the magnitude of evaporation flow vary on?
Location and season
What happens if there is lots of solar radiation?
There will be a large supply of water and warm, dry air, the amount of evaporation will be high.
What happens if there is not much solar radiation?
radiation, little available liquid water and cool air that is already nearly saturate, evaporation will be low
What does saturated mean?
Unable to absorb any more water vapour
What is condensation?
Water vapour changes state to become a liquid - loses energy to its surrounding
When does condensation happen?
When air containing water vapour cools to its Drew point
What is Drew Point?
The temperature changes from gas to liquid
What happens to water droplets?
Stay in the atmosphere or flow to other subsystems
What does the magnitude of condensation flow depend on?
The amount of water vapour in the atmosphere and the temperature
What is precipitation?
The main flow of water from the atmosphere to the ground
When do clouds form?
Warm air cools down, causing the water vapour in it to condense into water droplets and gather as clouds
What happens when the droplets aren’t big enough?
They fall as precipitation
What are other air masses?
Warm air is less dense than cool air. As a result when warm air meets cool air all the warm air is forced above. It cools down and rises
What is the result of other air masses?
Frontal Precipitation
What is topography?
When warm air meets mountains, it’s forced to rise causing it too cool
What is the result of Topography?
Orographic Precipitation
What is convection?
Sun heats up the ground, moisture on the ground evaporates and rises in a column of warm air. As it gets higher it cools
What is the result of Convection?
Convective Precipitation
Why are water droplets caused?
By condensation that are too small to form clouds on their own
What has to happen for clouds to form?
There has to be tiny particles of substances like dust to act as a cloud condensation nuclei
What does cloud formation vary on?
Season and location
Give 2 examples of Cryospheric processes
Accumulation and Ablation
What do cryospheric processes do?
Change the amount of water stored as ice
What does the balance of accumulation and ablation vary with?
Temperature
In Periods of global colds what are bigger inputs or outputs and why?
Inputs - Water is transferred to snow and less water is transferred away because of melting
In periods of warmer global temperatures what happens to the magnitude?
The magnitude of the cryoshere store reduces. as losses because of melting are larger than inputs of snow
Where are there extensive stores of Iceland Alpine Glaciers?
Antartica and Greenland
What is an example of a change that happens over a short time period?
Annual temperature fluctuations means more snow falls in winter
