R Flashcards
Radiation
The emission of energy as electromagnetic waves.
Radial drainage
A pattern of streams radiating from a central point or area e.g. off a mountain.
Radiation fog
A fog formed when warm moist air is cooled to the dew point by the ground.
Rain
Liquid precipitation from the atmosphere in drops of at least 0.5mm in diameter.
Rain gauge
An instrument used to quantify the amount of rain falling in a particular location over a period of hours.
Consists of a beaker marked out in millimeter intervals and a funnel leading into it.
The beaker will be set in open ground to avoid water from drips or splash.
Rainshadow
The area on the leeward side of a mountain range which experiences drier conditions than the windward side.
This is due to the air being drier as it has experienced condensation and precipitation on the windward side, plus the fact that the air will be sinking and therefore warming meaning relative humidity is falling and condensation cannot occur.
Rainsplash
Soil erosion caused by the force of impact of raindrops.
Raised beach
A relict beach left dry by a relative fall in sea-level.
Ramsar Convention
The Convention on Wetlands of International Importance especially as Waterfowl Habitat held at Ramsar in Iran in 1971.
Now known as the Convention on Wetlands.
Seeks to identify, conserve and use wisely, areas of wetland that may be under threat from human encroachment.
The Convention entered into force in 1975 and had 158 signatories lodged with UNESCO by 2009.
www.ramsar.org
Ranching
Vast, extensive livestock farms, usually found in remote, marginal areas which are not viable for other types of farming.
Range
In human geography, the maximum distance that people are willing to travel to obtain a good or service.
Accuracy is limited by multiple local factors plus the subjective nature of the idea, but generalizations can be drawn.
Rank-size rule
The size of a settlement is inversely proportional to its rank i.e. the second largest city is half the size of the largest etc.
If the largest city is much larger than all others, primacy exists.
If two cities are broadly similar and larger than all others then it is said to be a binary situation.
Rationalization
The reorganization of a company to increase efficiency, usually by cutting costs especially labour costs.
Ravine
Deep, steep-sided valley, gorge or cleft cut into a rocky landscape.
Raw materials
Unprocessed inputs to an industrial process.
Reforestation
This is the restocking of existing forests and woodlands which have been depleted, with native tree stock.
Reclaimed land
Artificial land created in coastal areas.
Recreation
Any activity people do during their leisure time. Some definitions require it to be activities away from home but that take up less than a day, after which they become tourist activities.
Recreational forest
Forests maintained for recreation activities such as bird-watching, cycling, horse-riding, camping etc.
Recycling
The re-use of materials that would otherwise be deemed rubbish.
Redevelopment
The regeneration of urban areas that have fallen into poverty and disrepair.
It may involve renewal of existing infrastructure, or wholesale demolition and rebuilding.
Red tide
A bloom of surface algae, red in colour, found in coastal waters when a heavy nutrient load is washed from the land stimulating the algal growth.
Reduction
A chemical reaction involving the removal of oxygen.
Refraction
The tendency for waves to become more parallel to the coastline as they approach it.
Caused by the slowing of waves at their base as they enter shallower water.
Refugee
A person who flees their home country through a fear of persecution on the grounds of race or religion, or membership of some other group.
Regelation
The refreezing of water into ice after pressure which caused it to melt is released.
Regeneration
See redevelopment.
Region
An area defined from its surroundings by common characteristics of physical landscape, economy or function.
Regolith
Rock material that has been weathered from the original bedrock.
Rejuvenation
The increased erosional activity of a river brought about by a relative fall in sea-level which means the river must flow further and at increased gradient thus giving it more energy.
Relative humidity
Ratio of water vapour in the air compared to the maximum possible at that temperature and pressure, expressed as a percentage.
Relief
The shape of the land particularly as it pertains to elevation.
Remembrement
The consolidation of fragmented land parcels, split by inheritance practices over many years, back into larger units.
Remote-sensing
The study of the surface from data gathered at high altitude by photography and other technology carried on aircraft and satellites.
Rendzina
A thin soil developed on limestone or chalk bedrock.
Renewable resources
Flows or living things which are either never-ending or grow quickly enough that their use does not lead to exhaustion.
Replacement rate
The fertility rate required to maintain a population at its current size.
It is 2.1 children per woman to allow both mother and father to be replaced.
Residential area
An area where the dominant land-use is for homes.
Residential type
The housing tenure of an area: owner-occupied, rented privately, or rented from the government.
Resource
Anything that we use for survival in the first place and wealth generation in the second.
May be natural, economic or human.
Resource management
The control of resources so that they do not become depleted or exhausted.
Respiration
The process in which an organism uses oxygen for its life processes and gives off carbon dioxide.
Resurgence
The reappearance of a river at the surface after it has spent some time running underground.
Common on limestone areas where the limestone is underlain by an impermeable rock.
Retailing
Sale of goods and services to the public.
Retail park
An out-of-town centre which allows several stores to operate around some shared resources such as car park and restaurants.
Ria
The flooded lower valley of a river caused by a relative rise in sea-level to form a small inlet.
Ribbon lake
Long, narrow, shallow lake formed in the bottom of a glacial trough due to a segment of over-deepening and / or blocking by deposits such as terminal moraine.
Richter scale
A measure of the total amount of energy released during an earthquake.
Runs from 1 to 10 on a logarithmic scale i.e. each level is ten times stronger than the one below.
Riffle
A bar-shaped deposit on a channel bed, midstream.
Rift valley
A valley created by the subsidence of land between two parallel faults undergoing tensile forces which pull them apart.
Rilling
A series of small channels which form on a slope after heavy rainfall.
Each channel may only be a couple of metres wide and half a metre deep, but they can develop into gullies if rainfall events are particularly frequent.
Slopes are often put at danger after ploughing.
Rime
Very heavy frost created when fog touches surfaces which are below 0˚C
River
An overland flow of water which forms a vital link in the hydrological cycle.
River capacity
The maximum amount of load a river can carry.
River capture
When the headwaters of one river are able to generate headward erosion and then break into another river channel and divert the flow into the new channel.
River cliff
Steep slope on the outer bend of a river where erosion allows for undercutting.
River profile
See long profile.
River regime
The variation in discharge over a year.
River terrace
Remnants of previous floodplains left higher than the existing river channel by increased erosion due to rejuvenation.
Roche mouton
Literally sheep-like rock.
Where a more resistant rock is passed over by a glacier the rock around it is removed more quickly leaving it protruding from the valley floor.
The upglacier side is smoothed by abrasion and covered by striations.
The downglacier side is rough due to plucking.
Rossby waves
The wave-pattern of flow of the westerly winds which blow in the upper atmosphere.
Thought to be the result of diversion of air flow around the Rockies and Andes, they change in both number and amplitude throughout the year.
Have a crucial impact on pressure systems in the troposphere and thus on mid-latitude climate.
Rostow model of growth
After W.W. Rostow who identified five stages of development in a national economy:
- Traditional society - mainly agricultural with limited, low-tech industry.
- Pre-conditions for take-off - capital investment in one or two industries along with investment in agriculture to free up labour.
- Takeoff - rapid growth in manufacturing, decline in agricultural employment - development of infrastructure.
- Drive to maturity - self-sustained economic growth and prolonged urbanization.
- Age of mass-consumption - expansion of service industry and decline in manufacturing.
Rotational movement
Slip or slide over a curved path.
Run-off
All water leaving a drainage basin.
Rural
Literally of the countryside.
Rural depopulation
The net movement of people to urban areas.
Rural settlement
Small settlements such as hamlets and villages, up to market towns which are tied to the countryside by function.
The distinction between rural and urban is increasingly unclear as people increasingly move away from urban areas and into rural settlements.
Rural-urban migration
The movement of people from rural areas to urban areas.
