The water cycle Flashcards
When does permafrost form?
When temperatures are so low in the air that the soil and groundwater freezes.
When did glacial periods start
2.58 million years ago
What is ablimation
occurs when outputs exceed inputs and glaciers melt
what is accumilation
where inputs of snow and ice exceed the outputs and ice caps increase
how many glacial periods have there been
5 meaning we are in quarternary glaciation
what are interglacial periods
when ablimation exceeds accumilation and the hydrological cycle as we know it returns
what happened in the last glacial period
- sea levels were approximately 120m lower than present
- glaciers covered large parts of Europe, North America, and Siberia
- represents interruptions in the hydrological cycle
what do we label the processes permafrost and glacial periodss
cryospheric periods
What’s are examples of inputs into the water cycle
infiltration- when water soaks through the soil
precipitation- when water is deposited onto ground (hail,snow, rain, fog)
percolation- water moving from surface layers of the soil into deeper layers of soil and rock
what is percolation
water moving from surface layers of the soil into deeper layers of soil and rock
what is an example of a store in the water cycle
groundwater store- water held below the water table in aquifers
what can be an output if the water exits the drainage basin
condensation- the process by which water vapour turns to water
what factors influence the evapouration rate of water
- the amount of solar energy
- availability of water
- humidity of the air (the more saturated the air is, the slower the rate of evapouration)
- temperature (warmer air holds more water)
What happens to air temperature when evaporation occurs
evaporation uses energy in the form of latent heat and so cools the air when it occurs
what is condensation and when does it occur
- excess water in the air is converted to liquid
- occurs when air cools and therefore is less able to hold water vapour
- if air is cooled sufficiently, it will get to a temperature at which it is saturated (dew temp)
what does water need to condense on
condensation nuclei or surfaces that are below dew point temperature
what happens if the condensation surface is below zero
the water sublimates changing from gas to solid in the form of frostl
what is overland or surface flow
tarmac surfaces or hard baked soil causes water to run along the surface
what is throughflow
water moving down hill through soil layers, the soil concentrates along roots and soil weaknesses
what is groundwater flow
water moving along rocks below the ground
what is intercetion
- plants trap precipitation
- some water flows down the stem as stem flow
- precipitation may evaporate directly off the leaf, never reaching the ground
what is evaporation
water changing from liquid to gas (water vapour) and it returning to the atmosphere
what is channel flow
water moving downhill within rivers- temporary store
what is evapotranspiration
combination of evaporation and transpiration (water leaving the leaf through the stomata)
- both are often grouped together so its easily calculated
what is positive feedback
cyclical sequence of events that amplifies or increases the change
- positive feedback loops exacerbate the outputs of a system
e.g. rising sea levels
what are open systems
mass and energy are allowed to transfer across a system boundary
what is a closed system
only energy can transfer across a system boundary
what is negative feedback
cyclical sequence of events that damps down or neutralises the effects of a system promoting stability
what is dynamic equilibrium
this represents the state of valence within a constantly changing system
the river exe highest point
514m in height in the north
the river exe lowest point
southern land much flatter- lowest elevation of 26m
how much of the river eve is underlain by impermeable rocks
84.4 % causing more runoff and throughflow and an extensive overlain drainage network
how much of the river exe is agricultural grassland
67%
How much of the river exe is arable woodland
15% (intercepts rainfall)
What is the land like in exmoor
peat bogs and moors
how urban is the river exe
only small amounts of urban land in Exeter which means there is more surface runoff in exeter
how big is wimbleball reservior
the size of 150 football pitches
where is wimbleball reservior
near exmoor peat bogs in the north of the river exe
what does the wimbleball reservior do
regulates flow and prevents peaks and troughs of water discharge stopping flooding and drought
when was the wimbleball reservoir constructed
1979
how do peat bogs influence the water cycle
peat bogs and mass hold lots of water, taking in nutrience
how do peat bogs influence the carbon cycle
peat holds co2, dry peat releases co2 whereas wet peat holds water and co2
what does the exmoor mires project aim to do
- aims to restore 2000 hectares of exmoor to boggy conditions
- opportunities or education due to increased biodiversity
what benefits has the exmoor mires project had on the water cycle
- more water storage in upper catchments
- increasing water capacity
- improved water quality due to throughflow
- less sediment carried into rivers
what benefits has the exmoor mires project had on the carbon cycle
less carbon released into the atmosphere
what are dipwells
- an electric contact diameter records the depth of the water table
- this is inserted into the dipwell and when the electrodes make contact with water
- a buzzer of light is activated and the depth measurement can be taken
was the exmore mires project successful
yes as its now finished and all of the aims have been met.
what are icecaps
- thick layers of ice that are=re smaller than 50,000km^2
- usually round in mountainous areas
- dome shaped
- polar regions
- Himalayas, southern alps
glaciers overview
- thick masses of ice found in deep valleys or upland hallows
- most valley glaciers are fed by ice caps or smaller glaciers
Himalayas glaciers
15000 Himalayas glaciers form a unique reservoir
sea ice overview
- much of the arctic ocean is frozen
- ice shelves are platforms of ice that form where ice sheets and glaciers move out into oceans
- mostly in Antarctica and greenland
what are iceburgs
chunks of ice that break off of glaciers
what is permafrost
soil or Rick ice that remains below 0 degrees for two consecutive years
ice sheets overview
- mass of glacial land ice extending more than 50,000km^2
- cover most of Greenland and antarctica
- contain more than 99% of the worlds freshwater
- form in areas where the snow that forms and falls in the winter does not melt in summer
oceanic water overview
- exact amount of water is still unknown
- covers approximately 72% of the planets surface
- contains 97% of the planets water
- only 5% of the ocean has been explored
why does the sea stay below 0 degrees
due to all of the dissolved salt
what ph is the ocean
oceans are alkaline with an average ph of 8.14
- seems to be stalling due to increased atmospheric carbon
- could effect ecosystems in years to come
atmospheric water
-clouds
-warmer bodies of air hold more water vapour
-positive feedback system (increases in atmospheric water vapour causes a rise in temp and further evaporation)
- exists in all three states
what does water vapour do to solar radiation
absorbs, reflects and scatters the radiation
what is polar air like
dry and equatorial (humid)
biological water overview
- consists of the water stored in all biomass
- varies widely around the globe
-trees take in water via roots - water is lost from plants via transpiration
groundwater overview
-water that collects underground in the pore spaces in the rock
-the depth at which soil pore spaces become completely saturated is called the water table\
-northern Russia has huge quantities of hot minaralised water at a depth of 13km
- scientists set a low level for ground water at 4000m
rivers overview
act as both a store and a flow of water
- the portion of the rivers drainage basin in Brazil alone is larger than any rivers basin
soil water overview
-soil water is a key variable in controlling the exchange of water and heat energy between the land surface and the atmosphere
- important role of the development of weather patterns and the production of precipitation
lakes overview
-collection of freshwater
- greater than two hectares in size
- large freshwater store
wetlands overview
-areas of marsh Peatland or water
- areas where water covers soil all year for various periods of time
- wetland vary widely because of regional and local differences in soils
- water saturation depends on the types of soil
