Support systems KQ1 The hydrosphere Flashcards
Why is water important to life on Earth? (Give 3 reasons)
Any from:
- oceans help to moderate global temperatures
- clouds reflect 1/5 solar radiation which lowers surface temperature
- makes up living organisms
- water vapour is a greenhouse gas
- used in chemical reactions in living organisms
Why is water important to humans?
- used commercially for manufacturing
- used in agriculture for irrigation of crops
- needed for chemical reactions
What is the hydrosphere?
The parts of the Earth made up of water
Why is the hydrological cycle?
The continuous movement of water driven by the sun and gravity
What type of system is the hydrological cycle?
A closed system
What are the two types of water on Earth?
Saline water and Meteoric water
What is largest store of water on Earth?
The oceans
What percentage of water on Earth is stored in the oceans?
97
What is the 2nd largest store of water on Earth?
Polar ice and glaciers
What is the smallest store of water on Earth?
Biosphere
What is the 3rd largest store of water on Earth?
Groundwater
What percentage of water is stored in polar ice and glaciers?
2
What percentage of water is stored in groundwater?
0.7
What percentage of water is stored in soils?
0.005
0.001% of the Earth’s water is stored where?
Lakes
What is the 6th largest store of water on Earth?
The Atomsphere
What is the 7th largest store of water on Earth?
Rivers
What is residence time in terms of the water cycle?
The average length of time water stays in a reservoir
Which reservoir of water has the shortest residence time?
Atmospheric moisture
Which reservoir of water has the greatest residence time?
Ice caps
What is the residence time of ice caps?
15,000 years
What is the residence time of groundwater?
Up to 10,000 years
What is the residence time of atmospheric moisture?
10 days
What is channel flow?
Flow of water in river channels
What is groundwater recharge?
The process by which groundwater is replenished by movement of water downwards to the groundwater store
By what process does groundwater recharge primarily occur?
Percolation
Why do clouds form?
When invisible water vapour in the air condenses into visible water droplets or ice crystals
What 5 things can cause clouds to form?
- Surface heating
- Topography
- Fronts
- Convergence
- Turbulence
How does surface heating cause clouds to form?
- Ground heated by the sun
- Heats the air in contact with the ground
- causing air to rise
How does topography cause clouds to form?
- air forced to rise over barriers such as mountains
- as the air rises it cools
How do fronts cause clouds to form?
-a mass of warm air rises over a mass of cold air
How does convergence cause clouds to form?
- streams of air flowing from different directions
- forced to rise when they converge
- as they rise, they cool
How does turbulence cause clouds to form?
- sudden change in wind speed with height
- creates turbulent eddies in the air
What are the 3 different types of rain?
- convectional rain
- relief rain
- frontal rain
How does convectional rain occur?
- produced by convectional clouds, formed in vertical motions
- when ground is heated water vapour rises
- air above ground is heated
- when air is heated from below gives smaller bubbles of rising air
- forming areas of rain
How does relief rain occur?
- result of clouds formed from topography of land
- with high ground moist air is forced up creating clouds and precipitation
How does frontal rain occur?
- when two air masses of different temperature and density meet
- the cold air is heavier than the warmer air
- warmer air is forced over the cold air
- as the warmer air rises it cools and forms rain
What % of moisture in the atmosphere comes from evaporation of lakes and oceans?
90
What % of evaporation from oceans reaches land in precipitation?
10
What 3 things control the rate of evaporation?
- temperature
- humidity
- air pressure
What is saturated overland flow?
- if more rain falls when soil is already saturated
- surface run off is produced
What is overland flow?
Occurs when rainfall intensity exceeds infiltration rate
What is the difference between saturated overland flow and overland flow?
- SOF occurs in well vegetated areas
- SOF occurs much later in a storm than OF
- OF occurs in deserts of other areas where soil infiltration capacity is reduced
What 4 things affect the rate of infiltration and throughflow?
- precipitation
- base flow
- soil characteristics
- soil saturation
How does precipitation affect the rate of infiltration and throughflow?
-amount, intensity, duration of precipitation which infiltrates into the ground over a period of time
How does base flow affect the rate of infiltration and throughflow?
- water in streams have a sustained flow even in periods lacking rain
- base flow comes from groundwater seeping into the bed and banks of a stream
How do soil characteristics affect the rate of infiltration and throughflow?
- some soils (clays) absorb less water at slower rate than sandy soils
- less absorbent soils = more runoff overland
How does soil saturation affect the rate of infiltration and throughflow?
- like a wet sponge, soil already saturated from previous rainfall can’t absorb more water
- so surface run off increases as saturation increases
How does water move through rock?
-gravity pulls water down though permeable rock, creating a water table
How do ice sheets form?
Through the accumulation of snowball
How do ice sheets lose mass?
Melting due to ablation
What are the effects on the water cycle as the % impervious surface increases?
- decrease in evapotranspiration
- decrease in deep infiltration
- decrease in shallow infiltration
- increase in runoff
- increases overland flow
- decreases groundwater flow
Explain the effect of urbanisation on evapotranspiration
- urban areas have lower levels of vegetation
- Evapotranspiration occurs from vegetation
- therefore less vegetation means less evapotranspiration
Explain the effect of urbanisation on groundwater flow
- urban areas have a high % impervious surfaces
- impervious surfaces reduce infiltration rates
- lower infiltration rates means less water in the ground
- so less groundwater flow
Explain the effect of urbanisation on river levels
- urban areas have high % impervious surfaces
- impervious surfaces reduce infiltration rates
- increases surface run off and overland flow
- after rainfall water gets into rivers more quickly
- increases river levels
