Water cycle Flashcards
Define a system.
A number of components, between which there are links.
In a system, what is transferred between the components?
Energy.
What 2 quantities exist within a system?
Energy and mass
What does the term ‘mass balance’ mean in systems theory?
The amount of mass in a system.
What are inputs in systems theory?
The transfer of any energy or mass into the system from its surroundings.
What are outputs in systems theory?
The transfer of any energy or mass out of the system into its surroundings.
What is a store in systems theory?
An accumulation of energy or mass.
What is a flow in systems theory?
The movement of energy and matter between 2 stores.
What are 2 other terms for ‘flow’ in systems theory?
- Flux
2. Transfer
What is a boundary in systems theory?
The external limit of the system; everything within its limits is in the system. The boundary distinguishes the system from its surroundings.
In systems theory, a system is bounded by what 2 things?
Space and time.
What is an element in systems theory?
Any part which makes up the system.
What is another term for ‘element’ in systems theory?
Component
What is an attribute in systems theory?
A measurable or perceivable characteristic of an element.
What are the 3 types of system?
- Isolated system
- Closed system
- Open system
What distinguishes between the 3 types of system?
Their inputs and outputs.
What is an isolated system in systems theory?
A system with no inputs or outputs. No energy or matter either enters or leaves the system.
Use 1 word to describe the energy balance and mass balance of an isolated system.
Finite
True or False? : Isolated systems exist.
False - Isolated systems are 100% theoretical and do not exist.
What is a closed system in systems theory?
A system with inputs and outputs of energy, but no inputs and outputs of mass.
What type of system do cycles tend to be?
Closed systems - here the finite balance of mass is recycled around the system in various forms.
What type of system is the Earth?
A closed system.
Why is the Earth classed as a closed system?
There is a negligible input and output of mass, which has virtually no effect on the planet’s overall mass balance.
What input to the Earth is virtually so small it has a negligible effect on the planet’s overall mass balance, hence the planet is classed as a closed system?
Meteorites
What output from the Earth is virtually so small it has a negligible effect on the planet’s overall mass balance, hence the planet is classed as a closed system?
Spacecraft (they also tend to return) and satellites.
What is an open system in systems theory?
A system with an input and output of both energy and matter.
Describe the mass balance of an open system.
Variable. It depends on the magnitude of inputs and outputs.
What is dynamic equilibrium in systems theory?
When the inputs entering the system are equal to the outputs leaving, thus there is no overall change in the energy or mass balance.
What is a feedback mechanism in systems theory?
Mechanisms employed to either increase or decrease the effect external change has on the dynamic equilibrium of a system.
What is a positive feedback mechanism in systems theory?
A response which amplifies the change in the equilibrium of the system, meaning that the system moves even further away from its previous state.
What is a negative feedback mechanism in systems theory?
A response which attempts to maintain the equilibrium of the system by counteracting the changes in inputs or outputs. It tries to bring the system back closer ti its previous state.
What are the 3 states that water may exist in?
Solid, liquid or gas.
What determines the state of water?
The energy it possesses.
What is the name for water in a solid state of matter?
Ice
What is the name for water in a liquid state of matter?
‘Water’
What is the name for water in a gaseous state of matter?
Water vapour
What is the process in which water changes from a solid to a liquid?
Ablation
What is the process in which water changes from a liquid to a solid?
Freezing
What is the process in which water changes from a liquid to a gas?
Evaporation
What is the process in which water changes from a gas to a liquid?
Condensation
What is the process in which water changes from a solid to a gas without becoming a liquid?
Sublimation
What is the process in which water changes from a gas to a solid without becoming a liquid?
Deposition
What is another term for deposition?
Desublimation
How old is the Earth?
4.5 billion years old
How did water end up on the Earth?
It was deposited on the planet by comets.
How much water is on the planet Earth?
1,386 million km3
What are the 2 types of water?
Saltwater and freshwater
What distinguishes between saltwater and freshwater?
Saltwater contains dissolved salts, freshwater does not.
What percentage of the Earth’s water is saltwater?
97.5%
What percentage of saltwater is stored in the oceans?
96.9%
What percentage of the planet is covered by the oceans?
2/3
What percentage of the water on the Earth is freshwater?
2.5%
What percentage of freshwater is located in the cryosphere?
68.7%
What are the 5 main cryospheric stores?
- Glaciers
- Ice sheets
- Ice caps
- Sea ice
- Permafrost
Where are the cryospheric stores located?
The high altitudes and the high latitudes.
What percentage of freshwater is stored as groundwater?
30.1%
What percentage of freshwater is stored in lakes?
0.26%
What percentage of freshwater is stored in rivers?
0.06%
What percentage of freshwater is stored in wetlands?
0.03%
What percentage of freshwater is stored as soil moisture?
0.05%
What percentage of freshwater is stored in the atmosphere?
0.04%
The water in the atmosphere could cause how many days’ worth of continual rain?
10 days
What percentage of freshwater is stored in the biosphere?
0.03%
What is residence time?
The average time mass spends in a store.
What is the residence time of soil?
1-2 months
What is the residence time of channel discharge?
2-6 months
What is the residence time of seasonal snow cover?
2-6 months
What is the residence time of glaciers?
20-100 years
What is the residence time of lakes?
50-100 years
What is the residence time of groundwater?
Up to 10,000 years.
What is the magnitude of a store?
The quantity of mass it contains.
What are the 2 processes which determine short-term changes in cryospheric storage?
Accumulation and ablation
What is accumulation?
The build-up of snow and ice in the cryosphere. An input into cyrospheric systems.
What is ablation?
The melting of snow and ice. An output from cryospheric systems.
What causes seasonal/short-term variations in cryospheric storage?
Temperature.
What are the 2 causes of long-term changes in cryospheric storage?
- The Milankovitch cycles
2. Plate tectonic movements
What are the Milakovitch cycles?
3 long-term natural processes which affect the orbit of the Earth around the Sun, bringing warming and cooling periods as they change the levels of insolation we receive.
How many Milankovitch cycles are there?
3
What are the 3 Milankotvich cycles?
- Change in orbit
- Change in tilt
- Wobbling of the axis
What is the 1st Milankovitch cycle and what does it do?
Change in orbit - every 100,000 years the orbit of the Earth changes from spherical to elliptical.
What is the 2nd Milankovitch cycle and what does it do?
Change in tilt - The Earth’s axis is currently titled at 23.5 degrees. Every 41,000 years, this changes between 22 and 24.5 degrees..
What is the 3rd Milankovitch cycle and what does it do?
Wobbling of the axis - every 22,000 years the axis wobbles.
How does plate tectonic movement affect long-term changes in cryospheric storage?
It moves the continents to other climatic zones.
How many planetary spheres are there?
5
What are the 5 planetary spheres?
- Lithosphere
- Hydrosphere
- Biosphere
- Cryosphere
- Atmosphere
What is the lithosphere?
The rocks and soil of the Earth.
What is an alternative name for the lithosphere?
The geosphere.
What types of hydrological stores are found in the lithosphere?
Groundwater and soil moisture.
What are the alternative names for the planetary spheres of the Earth?
The planetary domains or planetary sub-systems.
What is the hydrosphere?
All of the liquid water on the surface of the Earth.
What types of hydrological stores are found in the hydrosphere?
Oceans, seas, lakes and rivers.
What is the biosphere?
All of the life on Earth: flora and fauna.
What types of hydrological stores are found in the biosphere?
All of the water found in organisms.
What is the cryosphere?
All of the ice on Earth.
What types of hydrological stores are found in the cryosphere?
Glaciers, ice caps, ice sheets, sea ice and permafrost.
What is the atmosphere?
The layer of gases surrounding the planet Earth.
What types of hydrological stores are found in the atmosphere?
Water vapour, including clouds.
What is a drainage basin?
An area of land drained by a river and its tributaries.
What is the alternative name for a drainage basin?
A river’s catchment.
What is the name of the boundary of the drainage basin?
The watershed.
What is the watershed and how is it identified?
The boundary of the drainage basin, marked by a ridge of high land, beyond which any precipitation which falls shall drain into the adjacent basin.