Water cycle Flashcards
What % of earth’s water is in oceans?
97%
What is the PH of ocean water?
8.14 fallen from 8.25 over last 250 years
What are the 5 locations of cryospheric water
- sea ice
- ice caps
- ice sheets
- permafrost
- alpine glaciers
Why does sea ice not increase sea levels?
Its formed from sea water
What is an ice sheet?
Mass of glacial land ice extending over 50,000km2
Where are the 2 major ice sheets?
Greenland and Antarctica, 99% of freshwater ice
How are ice sheets formed?
Snow falls and does not completely melt, over thousands of years layers of snow pile up into thick masses of ice
What are ice caps?
Thick layers of ice under 50,000km, usually found in mountainous areas
What are alpine glaciers?
Thick masses of ice found in deep valleys or in upland hollows
What is permafrost?
Ground that remains below 0 degrees for at least 2 consecutive years (occurs in glacial periods)
What are the 4 classes of terrestrial water?
- surface water
- groundwater
- soil water
- biological water
What is surface water?
Free-flowing water of rivers as well as water from ponds and lakes
What are rivers?
- act as store and transfer of water
- streams of water within a defined channel
- cover 0.0002% of all water
What are lakes?
Collections of fresh water found in hollows on the land surface. Larger than 2 hectares.
What are wetlands?
- areas of marsh, fen and peatland
- dominance by vegetation
What is groundwater?
Water collects underground in the pores spaces in rock, depth of 4,000m
What is soil water
- Held together with air in unsaturated upper weathered layers of the Earth
- Fundamental for many hydrological and biological processes
What does soil water effect?
- weather/climate
- run-off potential
- flood control
- soil erosion
- reservoir management
Why is soil moisture important?
Controls exchange of water and heat energy between the land surface
Important role in weather patterns
What is biological water?
Constitutes the water stored in all the biomass
How many states can atmospheric water exist in?
3
solid, liquid and gas
What is evaporation?
Liquid->gas
Solar energy hits surface of water causing evaportation
What factors affect the rate of evaporation?
- solar energy
- availability of water
- humidity of air
- temperature of air
What is transpiration?
Water is transported from roots of plants to leaves and then lost through pores (stomata) on leaf surface
What is condensation
Gas->liquid
-occurs at dew point
What are the 2 main cryospheric processes?
accumulation and ablation
What period are we in now?
Quaternary period
What has happened during the quaternary period?
- Glacial periods where the sea level was 120m lower than now
- Interglacial periods where ablation exceeds accumulation
What is ablation?
Loss of mass of ice, melting
What is accumulation?
Build-up of ice mass,freezing
What is a drainage basin?
Area of land drained by river and its tributaries
What is groundwater flow
Slow movement of water through underlying rocks
What is infiltration?
Downward movement of water from the surface to soil
What is interception?
Precipitation that falls on vegetation surfaces cover that is temporarily stored on these surfaces
What is overland flow?
When water flows over the surface when the soil is full
What is percolation?
Downward movement of water within the rock under the soil surface, rates depend on nature of the rock
What does saturated mean?
Any water store that has reached its maximum capacity
What is stemflow?
Movement of water up or down a tree or plant
What is throughflow?
Movement of water through soil layer
What is throughfall?
Water from leaves to ground falls by throughfall
What factors affect infiltration?
- gravity
- relief
- capillary action
- soil porosity (texture, structure)
- topography
- vegetation
What is soil storage?
Amount of water that can be stored in the soil
How does soil store water?
It consists of solid particles with pore spaces between them which can be filled with water
Define saturated
When the infiltration capacity has been reached