System and Mass Balance (1) Flashcards
Attributes
The characteristics of the elements (eg hot/cold)
Relationships
A link between one store or component and another; along which something moves
Store / component
A part of the system where something is held for a period of time
Input
A point where something is added to the system
Elements
Things that make up the system
System boundary
The edge of the system; the interface (line) between one system and another
Output
A point where something is removed from the system
Flow/transfer
Descriptions of how the various elements work together to carry out a process
What’s an open system?
A system in which both mass and energy are allowed to transfer across system boundary. There may be a flow of matter as well as energy into or out of the system
What’s a closed system?
A system in which mass and energy are NOT allowed to transfer across system boundary. There are no external inputs or outputs. So, the system’s mass balance does not change over time.
Cryosphere
areas of the earth where water is frozen into snow or ice (includes ice sheets/ ice caps/ alpine glaciers / sea ice / permafrost)
Define ‘Dynamic Equilibrium’
Tendency towards a natural state of balance within a constantly changing system
Define ‘feedback’
when one element changes without a corresponding change - stores change and the equilibrium is upset
Define ‘positive feedback’
effects of an action are AMPLIFIED by the initial change
what’s permafrost
Permafrost is ground that continuously remains below 0° for 2+ years. Land or sea
Define ‘negative feedback’
Where the effects of an action are NULLIFIED by the initial change
Global scale of mass balance
At a global scale, mass balance means that the total amount of water is always conserved (although changes can occur in where it’s stored/ where it accumulates)
Local scale of mass balance
At a local (drainage basin) scale, system inputs = outputs, plus or minus any changes in store (or accumulation)
What is ‘blue water’
the visible part of the hydrological cycle (eg rivers, lakes). Water can also be stored in vegetation after interception or beneath the surface in the soil
What is ‘green water’
Water stored in the soil and in vegetation is known as ‘green water’; the invisible part of the hydrological cycle
Define ‘accumulation’
The build-up of snow and ice which takes place in the cryosphere
Define ‘ablation’
Ablation is the change from solid ice to liquid/water vapour when temperature rises above 0°.
This wastage of surface snow or ice is achieved by melting and evaporation
Define ‘ablation’
Ablation is the change from solid ice to liquid/water vapour when temperature rises above 0°.
This wastage of surface snow or ice is achieved by melting and evaporation
What is sublimation
Sublimation is the change from ice to vapour
What is the steady-state equilibrium?
The balance between ablation and accumulatation, which is usually maintained from year to year.
(This means that the system maintains balance when viewed over the longer term, despite any imbalances between inputs and outputs that exist for particular months or times of the year. Eg Arctic sea pack ice is reduced by 50% during summer, before reforming each winter)
What is the steady-state equilibrium?
The balance between ablation and accumulatation, which is usually maintained from year to year.
(This means that the system maintains balance when viewed over the longer term, despite any imbalances between inputs and outputs that exist for particular months or times of the year. Eg Arctic sea pack ice is reduced by 50% during summer, before reforming each winter)
Define ‘anthropogenic’
Human-induced
define ‘pedosphere’
soil layer that contains organic carbon as soil bacteria and remains of plants, and non-organic carbon from infiltration by acidic rain
Define ‘net balance’
difference between the total accumulation and total ablation during 1 year
