Water and Carbon Cycle Flashcards
systems approach
helps us to understand how energy and matter is transferred between components of a system and how those components themselves can change both naturally or due to human activity
systems approach - inputs
energy/matter fed into the system
systems approach - stores/components
energy/matter are held and not transferred until suitable processes are in place
systems approach - flows/processes
movement of energy/matter through the system
systems approach - outputs
outcome of processing and may be of use in the next element of the system
systems approach - stores of water
lakes, rivers, seas, icebergs, snow, groundwater plants, air
systems approach - transfers of water
melting, evaporation, condensation, precipitation, infiltration, percolation, surface run off, throughflow, groundwater flow
what are the 5 spheres?
lithosphere, hydrosphere, cryosphere, biosphere, atmosphere
systems approach + the water cycle - feedback
if inputs/outputs suddenly change then stores are forced to change + equilibrium is upset known as feedback
systems work on a balance of inputs and outputs producing dynamic equilibrium
positive feedback - effects of an action are amplified by changes to the inputs/outputs/processes
negative feedback - effect of an action are nullified by changes to inputs/outputs/processes
The Global Distribution of Water
The global hydrological cycle is the continuous movement of water on, above and below the earth taking the form of liquid, vapour and ice
Water is not evenly distributed
The Global Distribution of Water - hydrosphere (saline water in oceans)
a) how big is the store?
b) how does it vary spatially?
c) how does it vary over time in the long and short term?
(saline water in oceans)
96.5% of global water - supplied 90% of the evaporated water which goes back into the atmosphere
southern hemisphere has more water than northern which has more land
long-term: big fluctuations e.g. 18,000 years ago SL was up to 120m lower than present - 1/3 of world land area was covered with ice sheets/glaciers
short-term: relatively small eustatic change to sea levels, but general trend is SL as rising
The Global Distribution of Water - hydrosphere (saline water in oceans) - what happens during an interglacial and ice age?
Interglacial - water is added to hydrosphere store from the cryosphere, meaning more water available for the hydrological cycle, it speeds the cycle up
Ice age - water lost from hydrosphere to cryosphere so less water available, so hydrological cycle is slowed
The Global Distribution of Water - hydrosphere (fresh surface water)
a) how big is the store?
b) how does it vary spatially?
c) how does it vary over time in the long and short term?
(fresh surface water)
1.2% of global freshwater
lakes and rivers are not evenly distributed e.g. Caspian sea, Great Lakes of N. America
long + short term: level of these varies with climate (glacial/interglacial and varies seasonally)
The Global Distribution of Water - cryosphere
a) how big is the store?
b) how does it vary spatially?
c) how does it vary over time in the long and short term?
(ice)
68.7% of global freshwater, covers 10% of the earth’s surface, 95% is in Antarctica + Greenland
ice held in many forms: ice caps/sheets, glaciers, ice shelves, sea ice
long-term: variations with glacial + interglacial periods
short-term: seasonal variations, accumulation (build up of ice mass) + ablation (loss of ice mass) + calving (in winter glaciers accumulating less and in summer ablating more)
cryosphere - what are: ice caps/sheets, glaciers, ice shelves, sea ice
ice caps/sheets - land-based ice cover at least 20,000 square miles of land e.g. Antarctica, Iceland, Greenland
glaciers - cover less than 20,000 square miles of land
ice shelves - floating extensions of land ice
sea ice - free floating, saline water can freeze + thaw yearly e.g. Arctic
The Global Distribution of Water - lithosphere
a) how big is the store?
b) how does it vary spatially?
c) how does it vary over time in the long and short term?
(rock and soil)
groundwater 30.1% of global freshwater
soil moisture storage varies e.g. sand is porous + permeable so transfers water through it, storing very little + clay is porous but impermeable so stores water - stored in groundwater aquifers: rock that can store water e.g. Chalk and Sandstone, create vast underground reservoirs
long-term changes - depend of location (historical plate movements) and changes in climate
short-term changes (depends on the season + climate change)
The Global Distribution of Water - Atmosphere
a) how big is the store?
b) how does it vary spatially?
c) how does it vary over time in the long and short term?
0.001% of global water - 90% of water enters the atmosphere by evaporation + 10% by transpiration
spatially the amount of water in the atmosphere is determined by the tri-cellular model - convectional rainfall - orographic rainfall - frontal rainfall - sublimation (water changes from solid (ice/snow) to a gas, bypassing the liquid phase (occurs when there is low relative humidity + dry wins. Occurs more at higher altitudes where the air pressure is less than at lower altitudes. Energy, such as strong sunlight is also needed.
The Global Distribution of Water - biosphere
a) how big is the store?
b) how does it vary spatially?
0.26% surface freshwater
Distribution over space + time varies by biome + by season
Residence time of global stores of water: GS, G, GD, L, SSC, R, SM
Groundwater: shallow 100-200 years
Glaciers 20-100 years
Groundwater: deep 10,000 years
Lakes 50-100 years
Seasonal Snow Cover 2-6 months
Rivers 2-6 months
Soil moisture 1-2 months
Drainage Basin Systems - precipitation
water entering the drainage basin system through rain, hail, sleet or snow
Drainage Basin Systems - precipitation - factors causing the process or store to vary over time and/or space
type of precipitation
nature (intensity)
snow melt in spring
irrigation
Drainage Basin Systems - interception storage
precipitation which lands on vegetation
