OCR A Level ELSS - Entire Course 2 Flashcards
what is GIS?
-Geographic Information System.
-A computer that can capture, store, query, analyze, and display geographic data.
-analyses layers, spacial location and identifies any anomalies and trends
what are diurnal changes?
-significant changes that occur within a 24 hour period
-lower temperatures at night reduce evaporation and transpiration
-during the day convectional precipitation is dependent on direct heating of ground surface by the sun
-flows of carbon are reversed at night compared to day
what are seasonal changes?
-seasons are controlled by the variations in solar radiation
-in uk, solar radiation peaks in mid June (800 w/m2) in southern england
-compared to input of (150 w/m2) in December
-80% of precipitation is lost to evaporation in driest parts of lowland England, which exhausts soil moisture and river flows are lowest in late summer
how are seasonal changes reflected in the carbon cycle?
-month-month changes in the net primary productivity (NPP)
-in middle and high latitudes day length of photoperiod drive seasonal changes in NPP
-similar variations occur in tropics, but there main cause is water availability
carbon dioxide flows in the summer?
-net flow of CO2 from atmosphere to biosphere
-causes CO2 levels to fall by 2ppm
-at end of summer flow is reversed by natural decomposition releasing CO2 back to atmosphere
what are seasonal fluctuations in global CO2 flux explained by?
-concentration of continental land masses in the northern hemisphere
-during growing season, ecosystems such as boreal and forests extract huge amounts of CO2
from atmosphere which has a huge global impact
what happens during seasonal changes to phytoplankton in the oceans?
-in oceans phytoplankton are stimulated to photosynthesise by rising water temperatures, more intense sunlight and the lengthening photoperiod
-in northern Atlantic, ever year there is an explosion of microscopic ocean activity, resulting in algal blooms which peak in mid summer
impact of long term changes - how many major glacial cycles in the last 400,000 years?
-4 major glacial cycles in the last 400,000 years
-each last around 100,000 Years
-followed by warmer interglacials
temperatures at the height of the last glacial?
-20,000 years ago
-temperatures on average 5 degrees lower than they are today at the peak of the last glacial
what happened during the last glacial to most of the UK?
-scotland, Wales and Northern Ireland were submerged in ice up to 1km thick
impact on water cycle during glacial periods (sea level and sea ice)?
-in glacials sea level falls by 100-130m
-ice sheets expand over one third of the continental land mass
-ice sheets destroy forests and grasslands as they expand towards the equator
-lower rates of evapotranspiration reduces flows of water in the cycle
-overall water cycle decreases
impact on carbon cycle during glacial periods (temperature and CO2 concentration, oceans and phytoplankton ) ?
-dramatic reduction in CO2 in atmposphere
-glacial maxima concentrations fall to 180 ppm
-warmer interglacials they were 100 ppm higher
-close correlation between temperature and CO2 concentration
-more CO2 dissolves in oceans at lower SST as lower temperatures make the sea more soluble
-ocean circulation brings nutrients to the surface and stimulates phytoplankton growth
-overall a slowing carbon flux and smaller amounts of CO2 returned to atmosphere by decomposition
how are carbon and water cycles linked by the atmosphere?
-atmospheric CO2 has a greenhouse effect
-CO2 plays role in photosynthesis for plants and phytoplankton
-plants extract water from soil and transpire it to the atmosphere
-water is evaporated from the oceans to the atmosphere which causes CO2 to be transferred between both stores
how are carbon and water cycles linked by the ocean?
-ocean acidity increases when CO2 stores are unbalanced
-solubility of CO2 increases with lower SST
-CO2 levels influence SST, thermal expansion, air temperatures, melting of ice and sea level
how are carbon and water cycles linked by vegetation and soils?
-water availability influences photosynthesis, NPP, inputs of organic material and transpiration
-increased inputs of organic material to the soil increases the soils water storing capacity
-temperatures and rainfall affects decomposition and release of CO2
how are carbon and water cycles linked by cryosphere?
-CO2 levels determine the intensity of the greenhouse effect and melting of ice sheets, glacials and sea ice
-melting of ice exposes land which increases the absorption of solar radiation which increases temperatures
-melting of permafrost exposes dead organic material to decomposition and oxidation
-run off, river flow and evaporation respond to temperature change
what 4 anthropogenic factors have impacted the water and carbon cycles?
-urbanisation
-rapid population change
-deforestation
-economic change
=they have changed the size of stores and impacted most at local and regional scales
what has created shortages in the water cycle?
-rising demand for water for agriculture, irrigation and public supply
-human impact most evident on rivers and aquifers
what effect do anthropogenic factors have on the water cycle?
-decrease through flow
-lower water tables
-increase run off
-reduce evaporation and precipitation
where have human activities had a detrimental impact on the water cycle - examples?
-colorado basin, southwest USA
-surface supplies diminished as more water extracted from rivers
-huge amount evaporated from reservoirs in Lake mead and Powell
-bangladesh
-excessive water pumping of aquifers led to inclursions of salt water which makes the water unfit for drinking and irrigation
what are the impacts of deforestation?
-impact areas like Amazonia as forest trees play a huge role in the water cycle
-deforestation has decreased evapotranspiration therefore precipitation, breaking the cycle in some places which stops forest regeneration
how is human actives impacting the carbon cycle? (3)
-extracted billions of tonnes of carbon from the geological store
-the world relies on fossil fuels for 87% of the worlds total energy consumption
-land use changes, deforestation transfers 1 billion tonnes of carbon to atmosphere annually
-more CO2 absorbed by oceans due to more CO2 in atmosphere
-increases ocean acidity which kills phytoplankton
-soil degraded by erosion caused by deforestation and agricultural mismanagement
why has exploitations of coal, oil and gas stores increased rapidly recently?
exploitations of coal, oil and gas has increased rapidly due to the increasing industrialisation in India and china
Carbon cycle: burning fossil fuels transfers ____________________ of carbon to the atmosphere
8 billion tonnes
Carbon cycle: land use changes (deforestation) transfers ____________________ carbon to the atmosphere
1 billion tonnes
Carbon cycle: ocean acidification
-Ocean acidity increases when exchanges of CO2 aren’t in balance
-more CO2 dissolves into oceans when more co2 is in the atmosphere
-acidification kills phytoplankton
Carbon cycle: soil is degraded by erosion caused by what? (2)
deforestation and agricultural mismanagement
Carbon cycle: why are carbon stores in wetlands depleted?
When the wetlands are drained for cultivation and urban development they dry out and are oxidised
global warming leads to increased —– in the atmosphere?
leads to increased water vapour in the atmosphere
impact of long term changes on the water cycle?
-more water vapour in the atmosphere is a natural GHG
-vapour releases heat when it evaporates, cools and condenses which increases frequency of tropical storms
-global warming also accelerates melting of glaciers which transfers water from cryosphere to oceans + atmosphere
What does water release as it evaporates, cools and condenses?
heat
What could global warming increase the prevalence of and why?
hurricanes as they rely on warmer water
long term impacts of climate change on the carbon cycle - What does global warming lead to?
-higher temperatures increases rate of decomposition
-therefore accelerates flows of carbon from biosphere to atmosphere
-carbon stored in permafrost released to atmosphere
-acidification of oceans due to excess co2 in atmosphere kills phytoplankton, reducing rate of photosynthesis which limits oceans capacity of storing carbon
what changes occurs in stores of carbon due to long term impacts of climate change?
-less carbon stored in biosphere and ocean stores
-more carbon stored in the atmosphere
why is more carbon released to the atmosphere because of global warming? (2)
-higher decomposition rates
-melting of permafrost
Cloud formation
Creation of floating ice crystals or water droplets in the atmosphere, caused by rising moist air cooling at higher altitude and condensing
Catchment Hydrology
Water studies within a drainage basin
What is Permeable/Porous Rock?
Stone with lots of connected pore spaces, allowing the movement of water through it
What is a Drainage Basin?
The area of land where water and melted ice flows into a lake, sea or river
What is Relief?
The slope of the land - the steeper the slope, the faster the runoff, and the less time there is for infiltration to occur
What is Afforestation?
Planting trees in an area where there haven’t been trees before, removing CO2 from the atmosphere which is now locked within the trees’ biomass
Tropical Rainforest
Dense, multilayered woodland biome located up to 10degrees from the equator, where primary production is high and biodiversity correspondingly so
Tundra
Dry, high-latitude regions where the ground may be snow-free, but is frozen all year round. Northern Canada and Siberia are areas of this type
Negative Feedback
A cycle that returns a system back to its normal (equilibrium) state.
Positive Feedback
A ‘runaway’ system loop where the system moves further and further from equilibrium
Dynamic Equilibrium
A system with continuous inputs, throughputs, outputs and variable stores that fluctuates from year to year but, in the long term retains stability.
Artesian Basin
Pressurised groundwater found where permeable rock is overlain by impermeable rock, trapping water below, which entered at a higher elevation
Diurnal
Changes in the temperature between day and night - warmer during the day and coolest during the night
Seasonal Change
Alteration of the weather, temperature and precipitation throughout the year, as a result of the Earth’s tilt
Long Term
Time period spanning millions of years, for example
Importance of water on earth?
-oceans moderate temperatures by absorbing, storing and slowly releasing heat
-clouds reflect incoming solar radiation and lower surface temperatures
-water vapour absorbs long wave radiation from the earth and maintains global temps 15 degrees higher than they usually would be
Uses of water on Earth?
-Makes up 65-95% of living organisms and is vital for their growth, reproduction and metabolic functioning
-plants need water for photosynthesis, respiration and transpiration.
-water is used in all chemical reactions in humans and animals.
-important economic resource, used in agriculture, food manufacturing and to generate electricity.
Importance of carbon on earth?
-Life is carbon based, built on large molecules such as proteins, carbohydrates and nucleic acids.
Uses of carbon on Earth?
-economic resource, used in fossil fuels which power global economy
-agriculture, crops and forest trees store lots of carbon, used by humans for food, timber, paper, etc.
why is earth the only planet able to support life?
-climate - temperatures do not go from one extreme to the other
-light - all plants receive light from the sun which they need in order for photosynthesis
-atmosphere - breathable atmosphere, 21% oxygen and small amounts of CO2 (0..04%), atmosphere is kept on earth by gravity
-water - most important chemical needed to sustain life, drinkable and not acidic
-sun - in Goldilocks zone, right amount of heat and light to support life
spheres of the earth
-atmosphere (gas envelope surrounding the earth)
-biosphere (space between earth + atmosphere occupied by living organisms)
-lithosphere (crust + upper mantle, divided into tectonic plates)
-cryosphere (frozen part of earths surface)
-hydrosphere (all water on earths surface)
What is the Goldilocks zone?
-its ‘just the right distance’ from the sun to allow the presence of liquid water on earth
At a global scale, water and carbon flow in __________ systems (driven by the sun’s energy) between the ________________, the oceans, land and the _____________.
-closed
-atmosphere
-biosphere
The global water cycle consists of 3 main stores: the ______________, oceans and land. The oceans are the _____________ store and the atmosphere is the ______________.
-atmosphere
-biggest
-smallest
Water moves between stores by….
precipitation, evapotranspiration, run-off and groundwater flow.
Long term storage in sedimentary rocks holds…
99.9% of all carbon on earth.
Carbon in circulation moves rapidly between the…
atmosphere, the oceans, soil and the biosphere.
The main pathways between stores in the carbon cycle include…
photosynthesis, respiration, oxidation (decomposition, combustion), and weathering.
Systems are…
groups of objects and the relationships that bind the objects together
At smaller scales (drainage basin or forest ecosystem), ___________ as well as the sun’s energy cross system boundaries. These systems are….
-materials
-open systems
Sizes of stores of water?
Oceans- 97%
Ice caps + sheets- 2%
Groundwater- 0.7%
Lakes- 0.01%
Soils- 0.005%
Atmosphere- 0.001%
Rivers- 0.0001%
Biosphere- 0.00004%
Sizes of stores of carbon?
-Sedimentary rock- 60-100 million GT
-Ocean deep layer- 38,000 GT
-Fossil fuels- 4,130 GT
-Soil- 2300 GT
-Ocean surface- 700 GT
-Atmosphere- 600 GT
How much water does the global water circulate per year?
505, 000 km3 per year between stores
Inputs and outputs of water in the water cycle?
1)EVAPOTRANSPIRATION- water evaporates from surface water and land surface, and is transpired through leaves of plants
2)CONDENSATION + PRCIPITATION- occurs in atmosphere, vapour becomes liquid and is transferred to land as precipitation
3)ABLATION + SUBLIMATION- occurs when snow or ice melts, and sublimation occurs when ice turns into water vapour.
4)RUN OFF + FILTRATION - water runs off land surface into rivers, precipitation ends up as run off after infiltration in soil.
5)PERCOLATION- transfer of water to ground water stores (aquifers), returned to earth surface as springs.
Inputs + outputs of carbon in the carbon cycle?
1)PRECIPITATION-atmospheric CO2 dissolves in rainwater to form a weak carbonic acid, when precipitation happens CO2 flows back to lands and oceans- increased burning of fossil fuels increases acidity of rain + ocean water.
2)PHOTOSYNTHESIS - process by plants and phytoplankton, CO2 + water converted into glucose + oxygen, chemical energy stored in tissues
3)WEATHERING - involves the breakdown of rocks near earths surface by physical, mechanical and biological processes
4)RESPIRATION - process where glucose is converted back into carbon dioxide + water
-plants and animals absorb oxygen to burn carbohydrate stores to provide energy for metabolism and growth
5)DECOMPOSITION - carbon released as CO2 when organisms die by microorganisms carrying out respiration which also put mineral ions into soil
6) COMBUSTION - when organic material burns, CO2 locked up in the material is released with other gases like SO2
Evapotranspiration?
The evaporation of water from soil plus the transpiration of water from plants.
sublimation?
when ice turns into water
ablation?
when glacial ice or sheets melt to release water
infiltration?
Downward movement of water through soil.
run off?
water flowing off the land into bodies of surface water (for example, lakes or rivers).
what is water balance?
the relationship between precipitation, stream flow, evapotranspiration, soil moisture and ground water storage in a drainage basin over a year
The principal flows in the water cycle that link the various stores are:
precipitation, evaporation, transpiration, run-off, infiltration, percolation and throughflow.
percolation?
The downward movement of water through soil and rock due to gravity.
-Goes deep underground into an aquifer.
-Returned to earth’s surface as springs.
water cycle budget?
the annual volume of movement of water by precipitation, evapotranspiration, run-off etc. between stores such as oceans, permeable rocks, ice sheets, vegetation, soil, etc.
through flow?
A horizontal movement of water through the soil to rivers or oceans
base flow?
Water input to streams and rivers from natural reservoirs such as aquifers, pear bogs, soils etc.
interception loss?
rainwater stored temporarily on the leaves, stems and branches of vegetation which is evaporated and does not reach the ground surface
water balance equation?
precipitation = evapotranspiration + streamflow +/- storage
Process of the water cycle: Evaporation?
Requires a lot of energy to change state from liquid to vapour
Process of the water cycle:
Transpiration?
Transfer of water from plants to the atmosphere (10% of atmospheric water originates from transpiration).
-Influenced by temperature, wind speed and water availability to plants.
Process of the water cycle:
Precipitation?
-Water and ice that falls from clouds.
-Forms when vapour in the atmosphere cools to its dew-point temperature and condenses into tiny water droplets to form clouds.
-These droplets then aggregate, reach a critical size and leave the cloud as precipitation.
Process of the water cycle:
Condensation?
Change of water vapour to liquid, occurs when air is cooled to its dew point and clouds form.
4 ways that cause clouds to form?
Clouds form when moist air cools.
1)Air warmed by contact with ground or sea surface, rises through the atmosphere (convection). As the air rises and pressure falls it cools by (adiabatic) expansion.
2) Warm air mass meets cold air mass = forms stratus and cumuliform clouds
3) Large air mass moves across cooler surface = stratus
4) Air is forced to rise over elevated land (hills), causing it to cool.
Cumuliform clouds?
-flat bases, vertical development
-form when air is heated by the Earth’s surface
-causes air parcels to rise freely in the atmosphere, as the parcel of air cools and expands due to decreasing pressure, dew point is reached.
Stratiform clouds?
-Form when an air mass moves across a cooler surface (ocean). This is called advection.
-Low, white, little rainfall
Cirrus clouds?
-short, wispy clouds
- form at high altitude, consist of ice crystals.
-form after a warm front where air masses reach high levels
-do not produce rain, no impact on water cycle.
Condensation near the ground surface produces ______ and fog.
Both deposit large amounts of moisture on ______________.
-dew
-vegetation
Lapse rates…
Describe the vertical distribution of temperature in the lower atmosphere, and the temp changes that occur within an air parcel as it rises vertically from the ground.
What causes air to reach its water holding capacity (dew point)?
1) the amount of water in the air increases, and air cannot hold any more water
2)the air has cooled to its dew point, air cannot hold any more water
dew point
The temperature at which condensation begins
the two main sinks of carbon?
-sedimentary rocks - 60-100 million GT - 99.9% of the carbon store
-ocean deep layer - 38,000 GT - 2nd biggest store
what is GT - carbon store measurement?
billion tonnes
Describe the slow carbon cycle
-involves the long term store of carbon
-CO2 dissolves from atmosphere into ocean where marine organisms (shell fish and phytoplankton) make their shells and skeletons
-by fixing calcium and carbon to form calcium carbonate
-when they die, they accumulate on the ocean floor and over millions of years become compressed to form carbon rich sedimentary rock
-carbon stored in rock for 150 million years
-oceanic rock containing sedimentary rock is sub-ducted, causing it to melt and carbon is released during volcanic eruptions
-sedimentary rock on surface releases carbon when weathered
describe the fast carbon cycle
-transfer between stores is 10x faster than the slow carbon cycle
-land plants and microscopic phytoplankton in oceans are the key components
-absorb CO2 during photosynthesis, transforming it into carbohydrates stored in their tissues
-during respiration they release CO2 into the atmosphere by evaporation
sedimentary rock
-A type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together
the water and carbon cycle at global scales?
-considered as closed systems which are driven by the suns energy which is external to the earth and only energy crosses the boundaries / not matter
-carbon and water flow between atmosphere, oceans, land and biosphere
the water and carbon cycle at local scales?
-considered as open systems as materials and energy both cross boundaries
-ex = drainage basin or forest ecosystem
main processes of the water cycle?
-evaporation
-transpiration
-condensation
main inputs and outputs of water in the water cycle
-evaporation and transpiration
-ablation, sublimation, condensation, precipitation
-run off and infiltration
-percolation
what does residence time mean?
the length of time a molecule of water or carbon remains in natural storage
what are phytoplankton?
tiny photosynthesising marine organisms in surface waters of oceans
carbon cycle and precipitation?
-atmospheric CO2 dissolves in rainwater to form a weak carbonic acid
-when precipitation happens carbon flows back to lands and oceans
-as CO2 concentrations have increased in the atmosphere due to humans burning more fossil fuels, the acidity of precipitation has increased
-leading to acidity of ocean water
carbon cycle and photosynthesis?
-process used by land plants and phytoplankton to convert light energy into chemical energy
-CO2 + H20 - O2 + GLUCOSE
-chemical energy is stored in carbohydrate molecules such as sugars which plants use to maintain growth, reproduction and respiration
-glucose used as building block for cell walls, for respiration in plant cells and as an energy store
carbon cycle and weathering?
-involves the breakdown of rocks, near the surface by physical, mechanical and biological processes
-chemical weathering involves rainwater thats a weak carbonic acid which weathered rocks through carbonation or solution
-as the rock reacts with the carbonic acid it forms calcium bicarbonate which is soluble
-running water releases carbon into rivers and oceans
-physical weathering does not involve any altering of the carbon composition
-biological weathering involves chelation (organic acids) - as organic material decomposes it makes the soil become acidic which attacks rock minerals
carbon cycle and respiration?
-the process where carbohydrates formed in photosynthesis are converted into CO2 + water
-plants and animals absorb oxygen which allows them to burn carbohydrate store to provide energy needed in metabolism + growth
-respiration + photosynthesis are elements of the fast carbon cycle
carbon cycle and decomposition?
-carbon is released as CO2 when living organisms die and are decomposed by microorganisms
-decomposer organisms release CO2 into the atmosphere and extract mineral nutrients from the soil
-rates of decomposition depend on climatic conditions, which are faster in warm, humid environments
carbon cycle and combustion?
-when organic material burns, carbon locked up is released which other gases like SO2
-combustion can happen naturally by wildfires which are caused by lightening strikes
-benifical to ecosystem as it leads to an increase in nutrients and carbon cycling, leading to more growth
-due to a long winter, forest litter can build up on the forest floor therefore a fire releases the jam with nutrients and opens up the candy to create new habitats and increase biodiversity
-combustion happens due to humans actions for example deliberate firing of forests or grassland to clear space for cultivation or improve grazing quality
what is Catchment Hydrology?
Water studies within a drainage basin
what is a water basin?
a region drained by a river or its tributaries
catchment hydrology - 2 processes?
-evaporation
-interception
-
catchment hydrology - evaporation?
-evaporation is the phase when liquid water is converted into vapour
-heat energy is required break molecular bonds of water which is absorbed as latent heat and released later in condensation
-process allows huge amounts of heat to be transferred around the planet, for example from the tropics to the poles
catchment hydrology - interception?
-vegetation intercepts a proportion of precipitation storing it temporarily on branches, stems and leaves
-eventually this moisture evaporates or falls to the ground
-throughfall is when water is intercepted before dripping to the ground
-stemflow occurs during prolonged periods of rainfall when intercepted water may flow along branches and stems
factors effecting interception loss?
-interception storage capacity - as vegetation becomes saturated, output of water through stem flow and through flow increases
-wind speed - evaporation rates increase with wind speed
-vegetation type - larger surface areas (trees) have a larger interception losses than grasses
-tree species - some species have leaves all year round, some do not
infiltration, through flow, ground water flow and run off?
-rain falling to the ground and not entering storage follows one of two paths
1-infiltration by gravity into the soil and lateral movement to through flow to stream or river channels
2-overland flow across the ground surface as a sheet or as trickles to stream or river channels
-a few ideas explain the two paths, one is overland flow due to infiltration capacity
-second idea is due to rainfall always infiltrating the soil
what pattern does ground water stores follow?
-by late October the water table is beginning to rise as temperatures and evapotranspiration fall
-recharge continues until late January
-groundwater levels then decline throughout late winter, spring and summer, reaching their lowest point in early autumn
