water + carbon cycles Flashcards
System
A system is an assemblage of interrelated parts that work together by some driving force
Inputs
When matter of energy is added to the system
Outputs
When matter or energy leaves the system
Stores
Where matter or energy builds up
Flows
When matter or energy moves from one store to another
Boundaries
The limits of the system
Open system
Where energy and matter can enter and leave e.g. a drainage basin
Closed system
Matter can’t leave or enter, it can only CYCLE between stores e.g. the carbon cycle
Feedback:
- Positive
- Negative
The way a system responds to a change in flows or inputs is called feedback.
Positive feedback: when the effects of an action are amplified by changes to the inputs/ outputs/ processes.
Negative feedback: occurs when the effects of an action are nullified by changes to the inputs/ outputs/ processes.
What are the 5 sub- systems on earth?
- Cryosphere (ice)- all parts of the earth cold enough to freeze.
- Atmosphere (air)- the layer of gas between the earth’s surface and space, held in place by gravity.
- Hydrosphere (water)- al of the water on earth in solid or liquid form. Can be saline or fresh.
- Lithosphere (geology)- the outermost part of the earth, includes the crust and the upper parts of the mantle.
- Biosphere (organic life)- part of the earth’s systems where all living organisms are found. This includes all living animals, fungi, bacteria, insects, etc.
Fusion
When a solid becomes a liquid and vice versa
Vapourisation
When a liquid becomes a gas and vice versa
Sublimation
When a solid becomes a gas, skipping out the liquid phase
Latent heat (required for sublimation)
Molecules become heated by the sun but it doesn’t provide them with enough energy to break the bonds.
Water molecules absorb energy from their surroundings to give them final energy that they need to break the bonds between them. This energy is known as latent heat.
As latent heat is taken from the surroundings it cools the surroundings down.
Factors slowing the rate of evaporation
- temperature
- surface area
- wind speed
- humidity
Condensation
When condensation occurs the opposite happens.
- Latent heat is released by water molecules as they slow down and join together.
- Therefore condensation can be thought of as a warming process, evaporation is the opposite (cooling).
Total global water statistics
Oceans- 96.5%
Other saline water- 0.9%
Freshwater- 2.5%
Of that freshwater:
glaciers and icecaps- 68.7%
groundwater- 30.1%
surface/ other freshwater- 1.2%
What are the 4 main stores of water in the hydrosphere?
- Oceanic water- the water contained in the earth’s oceans and seas but not including inland seas such as the Caspian Sea.
- Atmospheric water- water found in the atmosphere, mainly water vapour with clouds and water droplets.
- Terrestrial water- groundwater, lakes, soil, wetlands and rivers.
- Cryospheric water- water locked up on earth as ice.
Sub-stores of crysopheric water
- Ice shelf- large areas of ice on the sea
- Sea ice- found largely in parts of the Arctic Ocean. Sea levels do NOT rise when this melts
- Ice caps- covers just less then 50,000km^2
- Permafrost- land frozen for 2 or more consecutive years
- Ice sheet- covers more than 50,000km^2
Sub-stores of terrestrial water
- Surface water- ponds, rivers and lakes. These are important as they are huge transfers and stores. e.g. they take water from land to oceans.
- Wetlands- main ecosystems of the arctic.
- Groundwater
- Biological- stored in biomass (all living and formerly living material).
Oceanic water
- approx 1,350,000,000km^3 of oceanic water. Av depth is 3,700km. Only 5% is explored. It covers 72% of the earth’s surface.
Atmospheric water
Water held within the atmosphere. Approx. 12,400km^3.
- water exists within 3 states in the atmosphere.
- DOUBLES with a 10 degree temperature rise.
What is a drainage basin? What kind of system is a drainage basin viewed as?
An area of land surrounding a river, from which a river receives water and subsequently drains water. In other words, the area surrounding the river where the rain falling on the land flows into that river. Also called the river’s CATCHMENT.
Drainage basins are viewed as open hydrological systems.
What is the boundary of a drainage basin called?
Watershed
Precipitation
Rain, snow, hail and sleet.
Infiltration
When water enters permeable surfaces.
Interception
When water is caught by trees and plants
Stem flow
Water running down a plant stem or tree trunk
Overland flow
Water flows over the lands surface by a river or channel
Through flow
Water flowing horizontally in the ground when the soil is saturated
Transpiration
Water is transferred from the roots to the leaves and then evaporates from the leaves into the atmosphere
Evapotranspiration
Total amount of evaporation and transpiration
Ground water
Water stored underground in bedrock
Soil water
Water held between soil particles
Groundwater flow
Slow movement of ground water through permeable rock
Percolation
Deep transfer of water into permeable rock
Surface storage
Volume of water stored on the earth’s surface e.g. lakes, ponds and puddles
Groundwater storage
Storage of water underground in permeable rock
Inputs of a drainage basin
Precipitation commonly rain but also includes snow, hail, dew and frost
Stores in a drainage basin
- Vegetation storage
- Interception storage (although this is only temporary as water may evaporate quickly).
- Surface storage, including puddles, ponds and lakes.
-Soil storage - Groundwater storage- stored either in the soil or rocks. Porous rocks are called aquifers.
- Channel storage
Flows in a drainage basin
- infiltration as water is soaked up into the soil.
- Overland flow (runoff). Can flow in small channels or over the whole surface.
- Throughfall- water dripping from one leaf (or another plant) to another.
- Percolation- water seeping down the soil into the water table.
- Groundwater flow- water flowing slowly below the water table through permeable rock.
- Baseflow- groundwater flow that feeds into rivers through river banks and beds.
- Interflow- water flowing downhill through permeable rock above the water table.
- Channel flow- water flowing into the river of stream itself (also called river DISCHARGE).
Outputs of a drainage basin
- Evapouration- water turning into water vapour.
- Transpiration is evaporation from within the leaves of plants and trees.
-Evapotranspiration. Two types: PET (potential that could occur and be lost and ACTUAL evapotranspiration is what actually happens. - River discharge or river flow
Water balance
The water balance is the difference between the inputs and outputs (and the subsequent change in storage) in the drainage basin.
It is worked out using precipitation, runoff and evapotranspiration.
- If precipitation exceeds evapotrns then and runoff there will be a POSITIVE water balance.
- If evapotrns and runoff exceed exceed precipitation = NEGATIVE water balance.
Equation for the water balance
P= Q+E +/- change in storage
OR
+/- change in S = P-(Q+E)
P= precipitation
Q= total runoff
E= evapotranspiration
Soil moisture budget
the change in the amount of water stored in the soil throughout the year
Main factors affecting the soil moisture budget
- precipitation
- potential evaporation
The river regime
the variability in a rivers discharge throughout the course of the year in response to precipitation, temperature, evapotranspiration and drainage basin characteristics
river discharge
how much water is in a river at a precise moment in time
equation for measuring discharge
CSA (cross sectional area) X velocity (speed)
what are the two controls on the level of discharge in a river
- volume
- speed
discharge is higher if there is lots of water in the river because lots can flow past you per second in M^3
if water is flowing fast then lots will flow past you per second therefore higher speed = higher discharge