Inputs. Outputs. Component/store. Section of a system where material or energy is held. Something that enters the system (material or energy)

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2 Inputs Something that enters the system (material or energy) Outputs Something that leaves the system (material or energy) Component/store Section of a system where material or energy is held

3 Transfer/flow The links between different components in a system Boundary Edge of a system (outputs cross the boundary to leave a system); where one system interacts with another.

4 Open system A system where energy and matter is transferred from the system across the boundary into the surrounding environment. Closed system A system where energy may transfer into and out of the system boundary but matter does not. Cascading A chain of open systems where the output of one system forms in input to another.

5 Dynamic equilibrium When there is relative stability in a cycle as the different stores have reached a state of balance, inputs, outputs and flows between stores continue but there is no overall change to the system. Positive feedback The system responds to a change by making the effects of that change larger so the system moves even further from its original state Negative feedback The system responds to a change counteracting the effects of the change so the system is returned to its original state.

6 Lithosphere The section of the earth s system made up of rocks and soil Hydrosphere The section of the earth s system made up of water. Usually defined as only liquid water but can also be used to refer to all water including ice. Cryosphere The section of the earth s system made up of stores of frozen water e.g. ice caps and ice sheets.

7 Atmosphere Gaseous layer of the earth s system surrounding the surface Terrestrial A term used to refer to things at the earth s surface e.g. terrestrial water = groundwater, soil moisture, wetlands, rivers and lakes. Biosphere All living things within the earth s system (terrestrial biosphere = living things on land, oceanic biosphere = living things in the ocean.

8 Magnitude Size of something Residence time The length of time that something is held within a particular store Spatial variations Variations in something over space e.g. how the volume of water present varies across the globe

9 L.O. To be able to describe the drainage basin water cycle and explain changes to the river regime

10 L.O. To be able to describe the drainage basin water cycle and explain changes to the river regime

11 Permafrost Soil or rock that remains below 0 degrees celcius for at least 2 consecutive years. Ice caps Ice layers smaller than km2 in size, usually a the peaks of upland areas Ice sheets Glacial land ice extending over km2 Other cryospheric stores = alpine glaciers, sea ice,

12 Condensation Water vapour changes state from a gas to a liquid as a result of a drop in the temperature and the dew point being reached. As the molecules join together, energy is lost as heat into the surrounding area. Evaporation Liquid water changes state into a gas as a result of an increase in temperature. As the water molecules separate, energy is released into the atmosphere.

13 Saturation point The point at which something can hold no more water saturation point of the air is the point where rain starts to fall. Transpiration Movement of water through plants some of which is then lost back into the atmosphere through stomata on leaves. Interception Trees catch precipitation on the leaves and branches. This water can be stored on the vegetation, eventually dropping to the ground or evaporating.

14 Evapotranspiration The total loss of water from a drainage basin via evaporation and transpiration. (Potential evapotranspiration = amount of evaporation possible in an area based on the temperature and vegetation present if there was sufficient water available. Sometimes potential evapotranspiration exceeds rainfall resulting in soil moisture utilisation deficit) Dew point The point at which the air is so cold that it can no longer hold water vapour so condensation occurs. Condensation nuclei Things around/on which condensation occurs e.g smoke or dust.

15 Cryospheric processes Processes that occur within and effect the cryosphere Accumulation when the amount of snow fall in winter is greater than the ice lost through melting in the summer so that the total volume of ice Ablation when the amount of snow fall in winter is smaller than the ice lost through melting in the summer so that the total volume of ice decreases.

16 Calving The breaking away of ice from ice shelves or ice sheets in to the sea to create icebergs Equilibrium line The height on a glacier where annual accumulation equals annual melting. The altitude of this line may vary in response to the climate.

17 Drainage basin water cycle The cyclical movement of water around the area drained by a river from the highland of the watershed down to the ocean and back into the atmosphere. Hill slope water cycle The cyclical movement of water between a hillslope, river channel and the atmosphere. Infiltration Movement of water into the soil

18 Percolation Movement of water into permeable rocks Groundwater / groundwater flow Water stored in rocks / movement of water through rocks downwards Through flow Movement of water through the soil downwards

19 Stemflow The precipitation that is intercepted by vegetation and then reaches the ground by flowing down stems and stalks. Discharge Volume of water in a river flowing past a particular point measured in cumecs (cubic metres per second). Impermeable Rock that water cannot percolate through

20 Water balance The balance between the inputs and outputs of water within a drainage basin. Change in storage = precipitation-(runoff + evapotranspiration) River regime The variations in a river s discharge throughout a year in response to temperature, precipitation, evapotranspiration and drainage basin characteristics. Soil moisture The volume of water (including vapour) that is stored in the soil.

21 Field capacity The amount of water that the soil can hold before becoming saturated. Wilting point When there is not enough water in the soil, that the plants have to use water from their own tissues in order to transpire. Once water is added, plants go out of wilting point. Soil moisture recharge The soil is filled back up with water after a period of deficit, this occurs when precipitation exceeds evapotranspiration.

22 Soil moisture deficit This occurs when evapotranspiration exceeds precipitation and soil moisture stores have been used up. Crops need to be irrigated and plants rely on adaptations to survice. This is the amount of water needed to refill the soil back up to field capacity. Soil moisture utilisation When evapotranspiration exceeds precipitation so that plants use up water from the soil stores, this lowers the water table and causes river levels to fall. Water surplus When the soils have become saturated following a period where evapotranspiration is lower than precipitation so that field capacity is exceeded.

23 Flood water Discharge that can no longer be held within the river channel Lag time The time between peak rainfall and peak discharge, which represents how long it takes for rainfall entering the drainage basin to reach the river Base flow The discharge in the river that is a result of groundwater flow.

24 Storm runoff The discharge in the river that is a result of the precipitation entering the river after the storm event Bank full discharge The maximum discharge a river can hold before the water overflows its banks. Drainage density The total length of all the streams and rivers in a drainage basin divided by the total area of the drainage basin. It is a measure of how well or how poorly a watershed is drained by stream channels.

25 Water abstraction Removing water from rivers or aquifers for human use Irrigation The controlled use of water to supply plants in order to encourage growth. Drainage density The total length of all the streams and rivers in a drainage basin divided by the total area of the drainage basin. It is a measure of how well or how poorly a watershed is drained by stream channels.

26 GtC Gigatonne of carbon = 1 billion tonnes Sedimentary rocks Rocks formed from compressed sediments e.g. limestone formed from compressed marine sediments Fossil fuels Natural fuels which release energy when burnt, composed of compressed, dead organisms. (coal=plants, gas and oil = plankton)

27 Marine sediments A store of carbon, primarily composed of calcium carbonate from dead oceanic organisms Soil organic matter Decomposed/decomposing organic materials. Permafrost Frozen layer of soil or rock that has remained frozen for at least 2 consecutive years. Organic material within this layer is unable to decompose.

28 Peat Partially decayed vegetation found in wetlands where the there is an almost permanent saturation with water so little oxygen is present. This means decomposition is slowed. Photosynthesis The process of using carbon dioxide, water and sunlight to create glucose and oxygen. This is done by plants and phytoplankton Respiration Conversion of oxygen and glucose into carbon dioxide, water and energy

29 Decomposition The break down of organic matter into smaller molecules carried out by decomposers. This releases carbon dioxide and methane. Some of the carbon is also transferred to the soil as humus. Photosynthesis The process of using carbon dioxide, water and sunlight to create glucose and oxygen. This is done by plants and phytoplankton and the carbon is then passed through the food chain. Weathering The breakdown of rocks in situ (where they are) by a combination of water, plants and animals. Atmospheric carbon reacts with water vapour to form slightly acidic rain. This dissolves rocks leading to molecules being transported into the sea. In the sea, they react with carbon dioxide to form calcium carbonate increasing the oceanic store of carbon

30 Combustion When organic material is reacted (burned) in the presence of oxygen to release carbon dioxide, oxygen and energy. (biomass combustion = burning of living and dead vegetation_ Carbon sink / reservoir A store that absorbs more carbon than it releases Carbon source A store that releases more carbon that it absorbs.

31 Burial and compaction Organic sediments are buried in layers at the bottom of the ocean, eventually these sediments are squashed (compacted) due to the weight of sediments above them. Carbon sequestration The transfer of carbon from the atmosphere into plants, soils, rocks and oceans. This can be done via both natural and human processes. Diffusion of carbon Carbon dioxide can diffuse from the atmosphere into water as it dissolves into cool water. Carbon dioxide can also diffuse out into the atmosphere, usually from warmer water.

32 Ocean pump Vertical deep mixing of carbon dioxide in oceans as cold water takes in carbon dioxide and sinks in high latitudes and then flows to lower latitudes where the ocean currents move to the surface and the carbon dioxide diffuses back in to the atmosphere. Biological carbon pump Marine organisms take in carbon, when they die their material sinks into deep water. Decomposition releases some carbon dioxide while the rest becomes part of marine sediments and eventually sedimentary rocks where the carbon can be stored for millions of years.