The Water Cycle Flashcards
Where is water stored on Earth?
> Less than 3% of the earths water is fresh with the rest being saline.
> Of the Earths Fresh Water -
\+ 69% is frozen in the cryosphere.
\+ 30% is groundwater.
\+ 0.3% in lakes and rivers etc.
\+ 0.04% water vapour.
What are some of the flows and stores of the closed global hydrological cycle?
STORES > Cryosphere. > Atmosphere - Water vapour and clouds. > Oceans, lakes and rivers. > Groundwater.
FLOWS Deposition Sublimation Evaporation Melting Infiltration Base flow Precipitation Condensation Freezing
INPUTS/ OUTPUTS
The suns energy.
How might evaporation effect the magnitude of the store?
> Evaporation occurs when liquid water changes state into a gas, becoming water vapour, it gains energy normally from solar radiation, it increases the amount of water stored in the atmosphere.
> The magnitude of evaporation varies by location and season, if there is lots of solar radiation and large supplies of water and warm,dry air the amount of evaporation will be high.
> If there is not much solar radiation, little available liquid and nearly saturated cool air evaporation will be low.
How might Condensation affect the magnitude of the store?
> Condensation is when water vapour changes state to become a liquid, loosing energy to its surroundings, it happens when air containing water vapour cools to dew point e.g when temperatures fall at night or when heat is lost to space.
> Water droplets can stay in the atmosphere or flow to other subsystems, e.g when water vapour condenses it can form dew decreasing the volume of water stored in the atmosphere.
> The magnitude of the condensation flow depends on the amount of water vapour in the atmosphere and the temperature, if there is lots of water vapour in the air and there is a large or rapid drop in temperature, condensation will be high.
What are the characteristics of cloud formation?
> Clouds form when warm air cools down, causing the water vapour to condense into water droplets which then form into clouds, when the droplets grow big enough they fall to the ground as precipitation.
THERE ARE SEVERAL THINGS THAT CAN CAUSE WARM AIR TO COOL LEADING TO CLOUD FORMATION AND PRECIPITATION:
OTHER AIR MASSES - Warm air is less dense than cool air and when it reaches cooler, denser air it is pushed above it, cooling as it rises, this is called FRONTAL PRECIPITATION.
TOPOGRAPHY - When warm air meets mountains its forced to rise causing it to cool this results in OROGRAPHIC PRECIPITATION.
CONVECTION - When the sun heats up the ground the moisture on the ground evaporates and rises up, as it gets higher it cools, this results in CONVECTIVE PRECIPITATION.
What are the three forms of precipitation?
1) FRONTAL PRECIPITATION- When warm air rises above cool air and cools.
2) OROGRAPHIC PRECIPITATION -
When warm air meets mountains it’s forced to rise causing it to cool.
3) CONVECTIVE PRECIPITATION -
When the sun heats up the ground it evaporates and rises before cooling with altitude.
How do Cryospheric processes change the magnitude of the store?
Processes such as ACCUMULATION AND ABLATION change the amount of water stored in the cryosphere varied by temperature.
> During global cold periods inputs into the cryosphere are larger than the outputs and vice versa in global warm periods.
The Earth is emerging from a global glacial period where coupled with the enhanced global warming effect is leading to more outputs than imputs.
> There are also annual temperature fluctuations with more ice being stored in the winter than the summer.
