The water cycle Flashcards
How much water does the hydrosphere contain?
1.4 sextillion litres of water
What is the type of water in the hydrosphere?
Most is saline in the oceans and less than 3% is freshwater.
Where is fresh water stored?
- 69% is frozen in the cyrosphere
- 30% is in groundwater
- 0.3% is liquid freshwater on the earths surface
- 0.04% is water vapour in the atmosphere
What must water be for humans to access it?
Must be physically and economically accessible for humans to use it.
How can water change?
Can change between solid, liquid and gas and for water to boil or melt it has to gain energy but for water to freeze or condense it has to lose energy.
What happens in the global hydrological system?
Water is cycled between different stores.
What type of system is the global hydrological system?
A closed system as there are no inputs or outputs of water.
How does the amount of water in a store vary?
Varies over a scale of local to global
What does the magnitude of a store depend on?
The amount of water flowing through them.
Where do different flows occur?
Occur at a range of temporal and spatial time scales.
When does evapouration happen?
When liquid water changes to a gas becoming water vapour and gains energy from solar radiation.
What does evapouration do?
Increases the amount of water stored in the atmosphere.
How does magnitude vary in evapouration?
Varies by location and season as if there is a lot of solar radiation, a large supply of water and warm, dry air evapouration increases.
What happens if there isn’t a lot of solar radiation with evapouration?
If there is little solar radiation, little available water and cool air that is nearly saturated evapouration will be low.
When does condensation occur?
When water vapour becomes a liquid and loses energy to the surrondings and happens when air containing water vapour cools to it’s dew point.
What happens with the water vapour droplets?
They can stay in the atmosphere or flow into other subsystems.
What the magnitude of condensation depend on?
Depends on the amount of water vapour in the atmosphere and the temperature as if there is plenty of water vapour in the atmosphere and a drop in temperatures then condensation increases.
What is precipitation?
The main flow of water from the atmosphere to the ground.
When do clouds form?
When warm air cools down causing water vapour to condense to water droplets which gather as clouds and when the droplets get big enough they fall as precipitation.
How do other air masses lead to preciptation?
Warm air is less dense then cool air so when the warm air meets the cool air the warm air is forced above the cool air and as it rises it cools which results in frontal precipitation.
How does topography lead to precipitaion?
When warm air meets mountains it is forced to rise which means it cools which leads to orographic precipitation.
How does convection lead to precipitation?
When the sun heats up the ground the moisture on the ground evapourates and rises into warm air and as it gets higher it cools which leads to conective precipitation.
What happens when water droplets are too small?
They are too small to form clouds on their own so there has to be other tiny particles of substances to act as coud condensation nuclei as they give nuclei a surface to condense on which encourages cloluds to form rather than allowing the moist air to dispense.
How does cloud formation and precipitation vary?
Varies seasonally and location.
