Key Definitions

• A geographical model helps us understand complex things. Eg demographic transition model. They are easy to understand, but can be complex to create.
• A system is a type of model, it is a diagram representing the different components and the relationships between them.
• Output of a system - material/energy moving from the system to the outside. Input of a system - material/energy moving into the system.
• Stores or Components are the individual elements of the system.
• Flows or transfers are the links between the components.
• Can have closed system eg household heating system or a open system eg a household water system.
• Subsystems are within a larger system eg a drainage basin within the water cycle.
• Isolated system - where there is no input or output of energy or matter. The system is continued to a boundary. This is very rare and the only true isolated system is the universe.
• Negative Feedback - where effects of an action are nullified by its subsequent knock on effects. Promotes dynamic equilibrium.
• Positive Feedback - where effects of an action amplify change. Promotes environmental instability.
• Cascading system - subsystems can be considered to be an open system that forms an interlocking relationship.
• Steady State equilibrium - all input and output components have achieved a state of balance and there is no change. Eg sand dunes.
• Metastable equilibrium - balance exists for most of the time but abrupt events shift the already steady state to a new equilibrium which then reverts to the steady state average. Eg a tropical storm - a quick change that then goes away.
• 'other saline water' refers to salt lakes etc
• 68.7% of freshwater is stored in ice and 30.1% is stored in groundwater/aquifers.
• Atmospheric water- water found in the atmosphere, mainly water vapour and ice crystals.
• Cryospheric water- water that is ice
• Hydrosphere - all of the water in earth
• Oceanic water- all water in oceans and seas, not including inland seas.
• Terrestrial water - water in/to do with the ground eg lakes and soil moisture
• All of the spheres will make connections to other spheres
• The ocean covers 72% of the earths surface.
• Surface water is rivers, ponds and lakes.
• Rivers are both a store and a transfer.
• A lake is over two hectares and a pond is under. The largest lake is the caspian sea.
• Wetlands - area where soil is water covered and water is present near the surface for long periods. - are the main ecosystem of the antarctic but are found almost everywhere.
• Soil water - soil and air in unsaturated layers of soil.
• Biological water - water stored in biomass.
• Elements are things that make up the system.
• Attributes are perceived characteristics of different elements.
• Fusion - solid to liquid. Vaporisation - liquid to gas. Sublimation - solid to gas.
• Interception - water intercepted and stored on the leves of plants.
• Overland flow - transfer of water over land surface.
• Groundwater flow - transfer of water very slowly through rocks.
• Infiltration - transfer of water from ground surface into the soil. It will then percolate into underlying rocks.
• Throughflow - water flowing through soil towards a river channel.
• Evaporation - cooling environment and Condensation - warming process
• Moving from solid to liquid to gas: water gains energy from the sun, starts to break bonds, absorbing energy from surroundings, this energy is called latent heat and the environment will be consequently cooled down.
• Meltwater - water from melted ice. Melt ponds - areas inside glacier that is still water.
• Between 2000 and 2019, glaciers lost 267 gigatonnes of ice a year, equivalent to 21% sea level rise.