S Flashcards
Salinisation
The deposition of salts at the surface of a soil in areas where evapotranspiration exceeds precipitation so drawing water up through the soil and with it salts that had been dissolved in it.
Sahel
A region in the centre of West Africa on the margins of the Sahara and prone to drought.
Saltation
The transport of load by bouncing along the bed of a river channel.
Salt marsh
An area of semi-vegetated tidal mudflat that becomes increasingly vegetated as sediments accumulate in sheltered waters allowing salt-tolerant plants to colonise them.
SALR
See saturated adiabatic lapse rate.
Saline
Of, containing, or concerned with salt (NaCl).
Salinity
Amount of salt in solution.
Salt lake
Inland body of water with a high salinity.
Salt pan
The dried out bed of a salt lake.
Sand
A particle of rock / mineral that has a diameter between 0.1 and 1.0mm.
Sand bar
A long strip of deposited sand lying offshore, usually only exposed at low tide, if at all.
Sand dune
A mound of sand deposited by wind in desert areas and along shore lines.
Sandur
See outwash plain.
Saprophyte
An organism which lives off other dead or dying organisms.
Satisficing
Accepting what is satisfactory rather than chasing the maximum possible outcome.
Saturated
Literally full of water - no more can be held.
Saturated adiabatic lapse rate
The rate of fall in air temperature by adiabatic change as saturated air gains altitude.
Varies between 4° and 9°C per 1000m - slower than the DALR as latent heat is released during condensation.
Savanna
The biome found in tropical areas either side of the equatorial zone between 10˚ and 20˚.
Scale
In general use refers to the size of an area or time period.
On maps, the scale indicates how many centimetres in the real world are represented by a centimetre on the map.
Scarp
The steep slope of an escarpment.
Scatter-graph
A graph which plots values by the use of dots.
The dependent variable usually goes on the y-axis and the independent variable on the x-axis.
The values are plotted as coordinates.
Scattering
The diffusion of insolation by particles in the atmosphere.
This radiation does not reach the surface as a result.
Science park
An industrial estate near a university or other research establishment where it is hoped cooperation between business and research can lead to the commercialization of technological advances.
Schengen agreement
An agreement by some members of the EU to remove all travel restrictions for their nationals across the borders of the members.
Scouring
See abrasion.
Scree
Highly angular rock pieces produced by freeze-thaw weathering and found at the base of a steep or vertical cliff face.
Sea breeze
A wind blowing from the sea to the land.
Sea-floor spreading
The widening of an ocean basin by the creation of new crust at a divergent margin.
Sea-level
Average elevation of the surface of the oceans.
Sea-level change
Two types:
- Eustatic - a change in the volume of water held in the oceans as climate variations change the amount stored as snow and ice.
- Isostatic - a change in the vertical position of the land due to the on-loading or off-loading of vast quantities of ice.
Seamount
An undersea volcano in a shield area.
Sea-wall
A steel and concrete wall built at the back of a beach, usually to protect a high value land area such as a town.
Sea-wave
At sea, waves represent a horizontal movement of energy but a vertical elliptical movement of water.
Secondary consumer
Any animal which feeds on primary consumers or other secondary consumers.
Secondary forest
Forest which is regrowing after the original vegetation was cleared.
Secondary sector
Manufacturing industry.
Secondary succession
The process of revegetation of an area that has been cleared for some reason.
Second world
Outdated term for the old communist bloc of the USSR and Eastern Europe.
Sectoral change
The general trend for the percentage of a workforce in agriculture to decline over time and for the secondary and then tertiary sectors to become increasingly important.
Sector model
Based on 149 US cities, an urban land-use model which accounts for transport routes within the city.
Suggests that industry and the wealthy make the first land-use decisions and the poor get whatever is left.
Sediment
Any material, of any size, which has been eroded / weathered and then transported and deposited by water, wind or ice.
Sedimentary rock
Any rock formed from sediments under pressure from other overlying sediments.
Sedimentation
The accumulation of sediment.
Sediment yield
Total amount of sediment moved by a river over time, usually in m³/km²/yr.
Seed dispersal
Movement of seeds away from parent plants.
Segregation
The location of particular groups of people into distinct areas separate from the general population, usually based on race, religion or economic circumstances.
Seif
A sand dune found in desert areas where the alignment is with the prevailing wind direction.
Seismic
Literally of an earthquake.
Self-employment
Work as a freelancer or owner operator.
Self-sufficiency
The ability to survive without outside help.
Separatism
The efforts of certain groups to create autonomous regions, or even achieve national independence, for a particular area within an existing nation-state.
Sere
A particular type of plant succession.
Sesquioxide
The oxides of iron and aluminium that occur in soils.
Set-aside
The policy within the EU, begun in the late 1980s, in which farmers are paid for keeping land out of production. Introduced to address the overproduction of food in these countries.
Settlement
A location where people have built structures to use as a base for their existence.
Settlement morphology
The pattern and / or shape of a settlement.
Shanty town
An area of informal housing built by its residents on the edge of a city.
The building materials are often waste from other sources and the land is occupied illegally.
There are no services and all quality of life indicators are very low.
Share-cropping
A system of land rent where the farmer pays with a percentage of his yield rather than cash.
Shield area
Ancient, stable area of crust away from plate margins and therefore unaffected by volcanic or earthquake activity.
Shield volcano
A volcanic cone made up of multiple layers of basaltic lava.
Shifting cultivation
A farming system in which a small tribal group cuts and burns the natural vegetation before cultivating the land.
After a number of years the land becomes depleted and the group moves to a new area.
The original land will recover after a period and the group usually rotates through three or four locations.
Shingle
The mixture of gravels, pebbles and shell fragments that accumulate on some beaches.
Shrub
A plant which has a thick woody stem but not thick or sturdy enough to be described as a trunk - smaller than trees.
Sial
Crustal material made mainly of silica and aluminium.
Silica (SiO2)
Most common mineral component of rock.
Sill
A sheet-like intrusion of magma between bedding planes.
Silt
A particle of rock / mineral with a diameter between 0.01 and 0.1mm.
Silurian
A period of geologic time lasting from 438m to 408m years ago.
Sima
Crustal material made mainly of silica and magnesium.
Sinkhole
See swallow hole.
Sinuosity
The curvature of a river course i.e. how far removed it is from a truly straight line course.
Site
The point at which a settlement is located.
Site factors
Those characteristics of a site which make it suitable for settlement.
Site of Special Scientific Interest
Sites having special and unique natural characteristics which are deemed worthy of legal protection.
Situation
The relationship of a settlement site to its surroundings and thus a factor in whether the settlement will grow or not.
Slash and burn
Another term for shifting cultivation.
Sleet
A form of precipitation where snow falls through warmer air and arrives at the surface partially melted.
Slip-face
The lee side of a sand dune so called because material often slides or rolls down it.
Slum
An area of old, rundown housing where living and social conditions are very poor.
Slump
See rotational movement.
Smelting
Processing of metal ore in order to extract the metal in its pure form.
The word is probably from the Middle German for “melt” and heat is indeed the main requirement but other chemicals (called fluxes) are required as catalysts and to deal with various types of impurities.
The exact temperatures and chemicals required will depend on the metal being extracted, the ore in which it is held, and the nature of the ground from which it was taken.
Smog
A mixture of smoke and fog produced by factory and domestic emissions which provide hygroscopic nuclei for condensation to occur.
Snout
The front end of a corrie glacier or valley glacier.
Social elite
The wealthiest section of society.
Snow line
Two types:
- The division between the zone of accumulation and the zone of ablation on a glacier.
- The elevation at which there is a division between snow covered and uncovered ground.
Snow melt
The spring and summer mass thawing of snow and ice which provides a sudden and massive increase in discharge to downslope rivers.
Social provision
The basic needs that a society should provide or aspire to provide for its members such as housing, healthcare, education and the like.
Soil
The very upper layer of the land surface made up of mixture of regolith, decomposed organic matter, air and water.
Soil conservation
The protection of a soil from erosion plus the maintenance of its fertility so that its productivity is maintained.
Soil creep
Slow mass movement of soil downslope due to outward expansions brought on by water infiltration which lead to downward movements under gravity as water moves out of the soil.
Soil fertility
The ability of a soil to provide nutrients for plant growth.
Soil profile
The variation in soil characteristics through its depth.
Soil structure
The pattern of aggregated soil particles into certain shapes of peds.
Soil texture
The ratio of sand, silt and clay within a soil.
Solar constant
The amount of energy received per unit area from the sun over a given period of time.
Solar radiation
See insolation.
Solfatara
A minor extrusive volcanic feature where gases escape from surface cracks and vents.
Solifluction
A mass movement of soil in periglacial areas when upper layers thaw in summer and are lubricated in comparison to the permafrost below.
Solute
Material dissolved in water.
Solution
The taking of minerals into water and removing them through flow.
Solution load
That portion of a river’s load held in solution.
Source
The start point of a stream or river.
Source region
The type of area from which an air mass originates.
Sovkhoz
See collective farm.
Spearman Rank Correlation Coefficient
A statistical measure of the degree to which two sets of data are correlated according to the formula:
Rs = (1 - 6 x ∑d²)/(n³ -n)
where d is the difference between the rank values of the data sets. While it can show how strongly data is correlated it is not a measure of cause and effect.
Specialization
At different scales, the concentration of effort into particular areas so that the efficiency and quality are maximized.
Sphere of influence
The area surrounding a settlement which is influenced by it in economic, political and social terms.
Spheroidal weathering
The chemical weathering of blocks of rock so that they take on a more rounded shape.
Spit
An embankment of sand which juts out from the land, often across a river mouth.
The unattached end is usually curved in towards the land.
Sediments may accumulate behind the spit to form salt marsh and eventually reclaimed land.
Sporadic permafrost
Mean annual temperature is just below 0˚C.
There may be isolated patches of frozen ground.
Spread effect
The transfer of resources away from a core area to a peripheral area due to diseconomies of scale.
Spring
The emergence of water from the ground, usually leading to the formation of a channel flow.
Spring-line
A line of springs emerging from a valley side at approximately the same height which reflect the underlying rock conditions.
Spring tide
Extremely high and low tides which occur twice a month when the sun and moon align on the same side of the earth and exert a combined gravitational pull on the oceans.
Squall line
A line of severe thunderstorms that can form along and/or ahead of a cold front.
SSSI
See Site of Special Scientific Interest.
Stability
When the DALR and SALR are both higher than the ELR then an air mass will be cooler than its surroundings and will sink back to its original position once the upward forces on it have ceased e.g. getting over a mountain range.
Stack
A pinnacle of rock standing just off a headland and formed when an arch collapses.
Stadial
A short-term advance of ice during a more general interglacial period.
Stalactite
A spindly deposit of calcium carbonate found hanging from the ceilings of caves in limestone areas. Water dripping from the ceiling releases carbon dioxide (reverse of carbonation) allowing the calcium carbonate to precipitate.
Stalagmite
A similar feature to a stalactite, formed by the same process, but found on the cave floor beneath the stalactite above. Tend to be shorter and more rounded due to the impact of the falling drip.
Staple food crop
The main crop which forms the basis of calorific content of the diet for a particular area.
Usually a carbohydrate food such as cereals or tubers.
State industry
One which is owned and operated by the government.
Stemflow
The flow of water down stems and trunks after interception of rainfall.
Steppe
The temperate grasslands of Eurasia which stretch from Hungary to Mongolia.
Stevenson screen
A white, usually wooden, box with louvre sides and raised on stilts used to hold thermometers at weather recording stations.
Stewardship
An approach to environmental management which advocates careful balance between development and protection of the environment.
Stilling well
A tube of wide diameter sunk into a river bank which thus allows an accurate and constant measurement of the still water surface level of the river itself.
Stokes Law
The settling rate of a particle in water is proportional to the diameter of that particle i.e. larger particles settle quicker.
Stone circle
A circle of large stones found in periglacial areas when the formation of an ice lens just beneath the surface creates a dome from which stones on the surface roll away.
Stone lines
They are long rows of stones piled together to form barriers across your field.
They do not store water.
They do something else that is important if you want to prevent erosion.
They slow the flow of water across your fields.
They work on both flat and sloping land.
They force the water to spread over the soil so that it can be absorbed into the soil instead of running off the field.
Storm beach
The highest part of a beach, created by a strong storm, which rests above the usual high water mark.
Storm surge
The pushing of water against a coastline to abnormally high levels, usually a combination of extreme low pressure and winds pushing water into a narrowing feature such as a bay or estuary.
Stoss
The exposed side of a slope.
Strata
Layers of deposited material.
Stratosphere
Layer of the atmosphere from approximately 12 to 50km. found above the tropopause.
Temperature increases with height due to absorption of solar energy.
Stratus cloud
A layered cloud found below 2.5 km which produces light drizzle.
Stream order
Classification of streams within a drainage basin so that it can be compared with another.
Different methods have been proposed with Strahler’s being most common.
From a source to a confluence, a stream is considered 1st order.
When two 1st order steams join, the resultant stream is a 2nd order stream.
Where two 2nd order streams join a 3rd is created and so on.
When streams of different orders join, the resultant stream remains as the higher order of the two that came together.
Striations
Scratch marks or grooves found on a rock surface that has experienced glacial abrasion.
Strip farming
The splitting of a larger field into smaller strips which are looked after by individual farmers.
Sub-aerial processes
All physical processes occurring at the surface.
Subduction
The movement of an oceanic plate beneath another crustal plate.
The plane of contact is known as the Benioff Zone where earthquakes occur.
Sub-glacial
Literally under the glacier.
Sublimation
Transformation between solid and gas, and vice versa, without being in a liquid stage.
Submergent plants
See aquatic plants.
Submergent features
Those formed where a coastline experiences a relative rise in sea-level.
Subsequent stream
A tributary created by headward erosion.
Subsidence
Sinking to a lower level.
Subsidy
A government grant used to save or stimulate a particular operation or whole industry sector.
Subsistence
Farming system where the farmer produces just enough to sustain himself and his family.
Succession
The development of a plant community over time.
Succulent
A plant that has adapted to drought conditions by being able to store water in its stem or leaves.
Superimposed drainage
A drainage pattern that formed on one set of rocks which have since been removed and so bears no relation to the set of rocks on which it is now found.
Supra-glacial
On the surface of a glacier.
Suspension
The transport of load in the body of the water in a river i.e. being carried along in the flow.
Sustainable agriculture
The increase in food yields without damage to the environment.
Sustainable development
Development strategies that do not compromise the ability of future generations to meet their needs.
Sustainable resources
Those resources which can be managed to provide an ongoing yield. Exploitation must not exceed renewal rates or they cease to be sustainable.
Swallow hole
The point at which a river channel may disappear underground. Usually found on limestone where joints may come to the surface and provide a conduit into which the river can disappear.
Swamp
An area, usually vegetated, permanently flooded or at least saturated by groundwater.
Swash
The running of water up a beach under the momentum of a breaking wave.
S-wave
A seismic wave which moves material in a motion perpendicular to the direction in which the energy of the wave itself is travelling.
Swell
See sea-wave.
Synoptic chart
A weather map.
System
Any set of components which are gathered into a working whole.
Systems theory
A theory designed to understand whole systems, including socio-ecological systems.
In a system, levels are linked in interdependent and interacting ways.
