5.1 Flashcards
What are fluxes in the global hydrological cycle
Fluxes measure the rate of flows between the stores
What are stores in the hydrological cycles
Stores are reservoirs where water is held e.g oceans
What is green water
Green water is water stored in the soil and vegetation ( invisible)
What is blue water
Blue water is water stored in rivers, stream lakes and groundwater in liquid form ( visible part of hydrological cycle)
How does water exist in the atmosphere
Water exists largely as vapour in the atmosphere, with the carrying capacity directly linked to temperature.
Where is water stored on land
On land water is stored in rivers, streams,lakes and groundwater in liquid form. It is often known as blue water. Water can be stored in vegetation after interception or beneath the surface in the soil . This type of water is known as green water
What is water stored as in the cryosphere
In the cryosphere water is largely found in a solid statement, with some in liquid form a s meltwater and lakes
How is the vast majority of water stored in oceans
In oceans the vast majority of water is stored in liquid form, with only a minute fraction as icebergs
What are the significant stores in the global hydrological cycle from smallest to largest
- Oceans are by far the largest stores of water as they contain an estimated 96.5-97 percent of the worlds total water
- The next largest store occur in the cryosphere which contain 1.9 percent of water
- The next largest store is groundwater which contains 1.1% of global water
- After that the next largest store is rivers and lakes which store 0,01 % of water
- The next largest store is soil moisture which stores 0.01%
- Atmospheric moisture is next after that storing 0.001 % of water
- Biological water ( biosphere is then last storing 0.0001 % of water
What type of system is the global hydrological cycle
The global hydrological cycle is a closed system driven by solar energy and gravitational potential energy
- In the closed system there is a fixed amount of water in the earth and atmosphere ( estimated at 1385 million km3)
- A closed system does not have any external inputs or outputs so this volume of water is constant and finite
- Water can exist in different states within the system and the proportions held in each of the states can vary for both physical and human reasons
What are processes in the global hydrological cycle
Processes are the physical mechanisms which drive the fluxes of water between the stores
What are the levels of fluxes between the atmosphere,oceans and land
Ocean to atmosphere :413 10^3km3 Atmosphere to ocean:373 10^3km3 Land to atmosphere =73 10^3km3; Atmosphere to land: 113 10^3km3 Transfer in atmosphere: 40 10^3km3
What is the global water budget
The global water budget is the annual balance of water flows and size of water stores
Why is there a lack of fresh water available to humans
- In the earths finite amount of water ( due to it being a closed system) only a small percentage is accessible freshwater (only 0.084% of total water)
- This is due to the large volumes in the salinous oceans (96.5%) and due to the volumes locked in glaciers , ice caps and frozen permafrost
- The location of the accessible freshwater means there is less available for humans, as large volumes are stored in locations remote from large population centres ( e.g lake Baikal in sparsely populated eastern Russia)
- Residence times are another factor affecting freshwater available for humans. Some of the largest freshwater stocks (e.g the major ice sheets in Antarctica and Greenland )store water as ice for very long periods ( up to 15,000 years according to ice core data).This means that water availability is reduced in some parts of the world for humans
- Another reason why there is a lack of freshwater available for humans is because stores with longer residence times are more likely to become polluted due to their increase in time in situ which means they are not available for humans
- One further reason why there is a lack of freshwater available for humans is due to the fact that fossil water stores( which occur as a result of pluvial periods ) (Lake Vostok , Antarctica)are not renewable and are not reachable for general human use, reducing the amount available for humans .
- Another reason why there is a lack of freshwater available for humans a is due to population rise. Population rise is having an affect on both the drinkability of Water due to pollution and climate change. It is also causing increased consumption of water and therefore increasing demand of already waining supplies of freshwater , causing problems with supply
What are the different percentages for freshwater stores
- 2.5% of water is freshwater
- Only 1.2% of freshwater is accessible surface water
- 68% of this is ground ice and permafrost, with the rest in more accessible forms such as soil moisture and rivers and lakes
- In total only 0.084% of total water is accessible freshwater
