unit 3 definitions Flashcards
remote sensing
It is the acquisition of information about an object or phenomenon without making physical contact with the object
passive sensors
absorb energy reflected or emitted
active sensors
provide the source of energy that is measured
spatial scale
the location and extent of features on Earth’s surface can be identified, measured and mapped (at a range of scales)
spectral scale
by looking at a range of wavelengths, different types of land cover can be identified and mapped, as well as the consequences of any land cover changes (e.g. degraded forests, silting in waterways)
temporal scales
due to the frequent repeating cycle of images being collected the rate and nature of change over time is easily identified and can be measured
land cover change modelling
Where scientists take images of existing land covers and, using computer software analyse the effects of a range of future scenarios to predict how land cover might change in the future
environments
The living and non-living elements of the earth’s surface
natural biomes
A community of life forms adapted to a large natural area
anthropogenic biomes
A global ecosystem unit defined by patters of sustained human interaction with ecosystems, creating a description of the terrestrial biosphere in it contemporary, human alters form
ecosystem
A description of the organisms (biotic) and physical (abiotic) features of environments including the amount and distribution of nutrients in particular
ecosystem dynamics
Are the network of interactions WITHIN the ecosystem community
affluence
Affluence is having increasing amounts of money or wealth
deforestation
The permanent removal of trees and often their associated vegetation for non-forest uses
expansion of agriculture
The expansion of agriculture refers to increasing the amount of land available which can be used for agricultural purposes
intensification of agriculture
Agricultural intensification is the increase of the productivity of land already used for agriculture through more inputs (such as fertilisers, machinery, labour, technology) in hope of increasing the outputs received from it
rangelands
Rangelands are ecosystems dominated by natural grasses, shrubs and some trees that are grazed by herbivores, such as grasslands, woodlands, wetlands and deserts that are grazed by domestic livestock or wild animals
land and soil degradation
The process by which the value of the land and soil is negatively affected by human induced changes
irrigation
the watering of land for agriculture
land drainage and reclamation
Land drainage involves water being removed from water logged land near lakes, rivers and deltas so that land can be used for other purposes. Reclamation often goes one step further creating new land from oceans, rivers etc
urban growth
Urban growth or urban sprawl refers to the outwards expansion of the urban area – usually in low density and often uncontrolled manner e.g. slums
mining
Mining is the process of extracting ore or minerals from the ground (such as coal or iron ore)
government policy
Governments can directly affect land use and land cover through the establishment of laws, regulations and policies
land degradation
Land degradation is the deterioration or loss of productive capacity of the soils for present and future
habitat destruction
the elimination or alteration of the conditions necessary for animals and plants to survive
urban heat islands
An urban heat island is a localised climate change – a metropolitan area that is significantly warmer than its surroundings
afforestation
Afforestation is largely a phenomenon of advanced industrial societies, which are both affluent and have high technological capacity and energy efficiency
spectral signature
the unique combination of wavelengths of energy reflected from that particular land cover
eutrophication
Caused by the release of excess nutrients into waterways from fertilisers dissolved in runoff from urban gardens and agricultural areas
heat budget
Refers to the balance between energy from the sun and the outgoing terrestrial energy lost to space
natural greenhouse effect
A phenomenon created by the energy radiated by the sun, the heat emitted from the Earth’s surface and greenhouse gases normally present in the atmosphere
enhanced greenhouse effect
Increasing the concentrations of the greenhouse gases due to human activities has led to increase in temperature
carbon cycle
the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth
carbon sinks
Natural store of carbon in rocks, oceans, biomass etc are relatively stable over long periods of time but can vary with changing conditions which have the ability to change climate
atmospheric circulation system
the large-scale movement of air and together with ocean circulation is the means by which thermal energy is redistributed on the surface of the Earth
hydrological cycle
The continuous movement of water through Earth’s environments, in the form of liquid water, gaseous water vapour or solid snow/ice
evaporation
change of state from a liquid to gas and occurs over water bodies but also from land surface
transpiration
loss of water vapour from plants through leaf pores
advection
movement of water as water vapour and clouds in the atmosphere blown by winds
condensation
process where gaseous water vapour changes to liquid water droplets once the dewpoint is reaches
sublimation
change of state from gas to solid or vice versa, without passing through a liquid phase (snowflakes from in atmosphere)
precipitation
movement of liquid or solid water from the atmosphere back to the Earth’s surface
convectional rainfall
results from hot energy from earth’s surface transferred to air above, which becomes less dense as it rises creating low pressure. As it rises, it cools and the water vapour contained in the air condenses to form
frontal rainfall
associated with sub-polar lows where converging air masses meet. Warmer air is displaced by cold air, eventually cooling as it rises, condensations of water vapour, clouds and rain follow the front
orographic rainfall
moist air is forced to rise due to the presence of a physical barrier. Mountain ranges block the flow of air masses, forcing air to rise to pass over mountains. The rising air cools, condenses, clouds form and rain falls on the windward side of the mountain. The air that passes over is relatively dry and results in a rain-shadow on the inland side
surface runoff
water that falls on the lands surface and flows along the surface, downhill, collecting in streams, rivers, lakes and ultimately flows back to the ocean
infiltration
infiltration is the water soaking into the soil surface, percolations refers to deeper downwards movement of water through the soil profile
groundwater flow
flowing and stored groundwater underground within the layers of soil and rock – stored in aquifers (Leederville aquifer) and often slowly flow back to ocean
climate change
Climate change is a long-term shift in global or regional climate patterns or average atmospheric conditions
ice age
permanent ice on land
glacial-interglacial cycles
Within an ice age, individual pulses of extra cold (glacial) and warmer (inter-glacial) periods exist
obliquity
Refers to the degree to which Earth is tilted on its axis and 41,000 year cycle between 22° to 24°
precession
Refers to the way in which the Earth wobbles on its axis like a spinning top and 26,000 year cycle
eccentricity
Refers to regular changes in the shape of the Earth’s orbital path around the sun and 100,000/400,000 year cycle
urban heat island effect
Local scale climate change (heating of urban areas relative to surrounding rural areas) due to physical differences between land cover
albedo
Albedo is the proportion of light (insolation) that is reflected by the Earth’s surface
