Flashcards in The Water Cycle - Stores 3112 Deck (57):
What is atmospheric water?
Water found in the atmosphere, mainly water vapour with some liquid (clouds and droplets) and ice crystals.
What is cyrospheric water?
The water locked up on the earths surface as ice
What is the hydrosphere?
A discontinuous layer of water at or near the earths surface, including all liquid and surface waters, groundwater held in soil and rock and atmospheric water vapour.
What is oceanic water?
The water contained in the earths oceans and seas, but not including inland seas e.g Caspin sea.
What is terrestrial water?
Groundwater, soil water, lakes, wetlands and rivers
What percentage of water on earth is oceanic water?
What percentage of water on earth is fresh water?
How is the total global 3% fresh water further broken down into individual stores?
79% = ice caps and glaciers
20% = groundwater
Easily accessible fresh water = 1%
What stores is the 3% of global fresh water found in?
Cyrosphere, terrestrial and atmospheric
What is important to note about the water stores? (Relating to dynamic equilibrium)
The amount of water in these stores is in a state of dynamic equilibrium with changes at a range of timescales from diurnal to geological.
What is important to note about atmospheric water?
Changing amounts of atmospheric water in the future could be a major cause and /or important impact of climate change. It is the most important greenhouse gas and major factor in determining climate change.
Why is understanding the complexities of the global water stores vital?
If we want to manage the vital resource it is essential
OCEANIC WATER: how much of the earth is covered by oceanic water?
OCEANIC WATER: what percentage of the world's water has been explored?
OCEANIC WATER: why are the oceans salty?
It contains dissolved salts. These salts allow it to stay as a liquid below 0 degrees Celsius. They are alkaline with an average PH of 8.14, the PH has fallen from 8.25 in the last 250 years and it seems destined to continue falling. This change in PH is linked to the increase in atmospheric carbon and may have a profound affect on marine ecosystems.
CRYOSPHERIC WATER: What are the five stores of Cryospheric water (ice):
1. Sea Ice
2. Ice caps
3. Ice sheets
4. Alpine glaciers
CYROSPHERIC WATER: what is sea ice and how does it form? (+ example)
Sea ice forms when water in the oceans is cooled to temps below freezing. It does not raise sea levels when it melts as it had already formed from ocean water so takes up the same volume when frozen or melted. Much of the Arctic Ocean is frozen, the amount frozen shrinks in summer and grows in winter and the same is true for waters surrounding Antarctica.
CRYOSPHERIC WATER: What is an ice sheet and how does it form?
An ice sheet is a mass of glacial land extending more than 50,000km squared. Ice sheets form in areas where snow that falls in the winter does not entirely melt in the summer, over thousands of years the snow piles up into thick masses of ice growing thicker and denser as the weight of new snow compresses the older layers.
CRYOSPHERIC WATER: what are two examples of Ice sheets?
The two major ice sheets that cover the earths surface today cover most of Greenland and Antartica.
- together the Antarctic and Greenland ice sheets contain more than 99% of the freshwater ice on earth.
- the Antartica ice sheet = extends almost 14 million km2, roughly the area of the USA and Mexico, it contains 30 million km3 of Ice. If it melted scientists estimate sea levels would rise roughly 60 metres.
- the Greenland ice sheet extents about 1.7 million km2 covering most of the island of Greenland. If the sheet melted scientists estimated sea levels would rise 6m.
CYROSPHERIC WATER: how does an ice sheet remain stable?
As long as the ice sheet accumulates the same mass of snow that it loses to the sea, it remains stable.
CYROSPHERIC WATER: what are ice caps?
Ice caps are thick layers of ice on land that are smaller than 50,000km 2 usually found in mountainous areas. Ice caps are usually to be dome shaped and centred over the highest point of an upland area.
CYROSPHERIC WATER: what is an alpine glacier?
A thick mass of ice found deep in valleys or in upload hollows.
CYROSPHERIC WATER: what is permafrost?
Ground, soil, rock, ice, organic material (the ground) that remains at or below 0 degrees for at least two consecutive years.
CYROSPHERIC WATER: how thick is permafrost?
the thickness of permafrost varied from less that 1 metre o more that 1,500 metres.
CYROSPHERIC WATER: when did most of the permafrost existing today form?
During the cold glacial periods and has persisted through warmer interglacial periods, including the Holocene (the last 10,000 years)
CYROSPHERIC WATER? Why does the melting of permafrost have a negative impact?
It releases large amounts of carbon dioxide and methane affecting global climates.
TERRESTRIAL WATER: what are the four broad categories of terrestrial water?
Surface water, groundwater, soil water, biological.
TERRESTRIAL WATER: what is surface water?
The free flowing water of rivers, as well as the water of ponds and lakes.
TERRESTRIAL WATER: what are the three categories of Surface water?
Rivers, lakes, wetlands
TERRESTRIAL WATER: how much global water do rivers store?
TERRESTRIAL WATER: what is the largest river in the world ( by discharge of water)?
The Amazon in South America, it accounts for roughly 1/5th of the world total river flow.
TERRESTRIAL WATER: what is a lake?
A collection of fresh water found in hollows on the lands surface, deemed a lake if greater than two hectares in area, anything smaller is deemed a pond.
TERRESTRIAL WATER: what are the majority of global lakes and where are they situated?
Majority are freshwater and are situated in the northern hemisphere at higher latitudes.
TERRESTRIAL WATER: what two countries have the most amount of lakes?
Canada = 2 million lakes
Finland roughly = 190,000
TERRESTRIAL WATER: what is the largest lake in the world?
Caspain sea at roughly 78,00km3 it is a reminder of an ancient ocean and is about 5.5 million years old, it is becoming more saline in the south where rivers are flowing into it.
TERRESTRIAL WATER: what is a wetland?
An area of marsh or peatland where there is dominance of vegetation.
TERRESTRIAL WATER: describe a wetland?
An area where water covers the soil or is present either at or near the surface of the soil all year or for varying periods of time during the year. Wetlands may support aquatic and terrestrial species. Wetlands are found on all continents apart form Antartica.
TERRESTRIAL WATER: what is the world's largest freshwater wetland system?
The pantanal of South America, it extends through millions of hectares of central-western Brazil, Eastern Bolivia and Eastern Paraguay it is a system of complex marshlands and lagoons and provides economic benefits by being a huge area for water purification, climate stabilisation, water supply, food abatement and an extensive transport system.
TERRESTRIAL WATER: what is significant about wetlands in the Arctic?
Wetlands are the main ecosystem in the Arctic, covering nearly 60% of the total surface area. They store enormous quantities of greenhouse gauges and are critical for global biodiversity.
TERRESTRIAL WATER: what is groundwater?
Water that collects underground in the pore spaces of rock.
TERRESTRIAL WATER: where is just over 30% of all fresh water stored?
In rocks deep below the grounds surface forming vast underground reservoirs called aquifers.
TERRESTRIAL WATER: what is an aquifer?
An underground layer of water
TERRESTRIAL WATER: where do aquifers form and how?
They most commonly form in rocks such as chalk and sandstone which a porous, (contain pores - air pockets) and percolate (allow water to pass through the cracks and fractures). Water can enter the rock directly or via overlying soil.
TERRESTRIAL WATER: (aquifers) what is the water table?
The depth at which rock becomes completely saturated with water
TERRESTRIAL WATER: (aquifers) the water table level rises and falls in response to what?
Groundwater flow, abstraction by people or recharge (additional water flowing into the Rock).
TERRESTRIAL WATER: how does groundwater flow to the earths surface?
As springs or can form oases or wetlands
TERRESTRIAL WATER: why is the amount of available groundwater reducing rapidly?
the amount of of available groundwater is reducing rapidly due to extensive extraction for uses in irrigation agricultural land in dry areas
TERRESTRIAL WATER: what is soil water?
Water held in the upper weathered layers of the earth. It is of fundamental importance to many hydrological and biological processes.
TERRESTRIAL WATER: why is soil water of fundamental importance to biological and biochemical processes.
It affects climate, run off potential and flood control, soil erosion and slope failure, reservoir management, geotechnical engineering and water quality. Soil moisture is a key variable in controlling the exchange of water and heat energy between the land surface and the atmosphere through evaporation and plant transpiration. As a result soil moisture plays an important role in the development of weather patterns and the production of precipitation.
TERRESTRIAL WATER: what is biological water?
Water stored in all the biomass.
TERRESTRIAL WATER: what does amount of biological water depend on?
It varies widely around the globe depending on Vegetation cover and type e.g areas of dense rainforest store much more water than deserts. The role of animals as a water store is minimal.
TERRESTRIAL WATER: what is an example of biological water?
Trees take in water via their roots. This is either transported or stored in the trunk and branches. The water is lost by the process of transpiration through stomata in the leaves. This storage provides a reservoir of water that helps maintain some climatic environments. If the vegetation is destroyed, this store is lost to the atmosphere and the climate can become more desert like. Many plants are adapted to store water in large quantities. Cacti are able to gather water via their extensive root-system and then very slowly use it until the next rainstorm.
ATMOSPHERIC WATER: what are the three stages?
Gas, liquid, solid.
ATMOSPHERIC WATER: what is the most common atmospheric water?
Water vapour (gas). Water vapour absorbs, reflects and scatters solar radiation keeping the atmosphere at a temperature that can maintain life.
ATMOSPHERIC WATER: the amount of water vapour that can be held by air depends on what?
Temperature, cold air cannot holders much water vapour as warm air. Therefore the poles are dry and the air over the tropics is much more humid.
ATMOSPHERIC WATER: what is a cloud and how does it form?
A cloud is a visible mass of water droplets or ice crystals suspended in the atmosphere. Cloud formation is the result of air in the lower atmosphere coming saturated, with the cloud droplets grow they can eventually fall as rain