OCR A Level ELSS - Entire Course 2 Flashcards
(120 cards)
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