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Tectonic -
The geological processes
by which rocks are deformed and that produces features of
the earth's crust.
Temperate moderate or mild
conditions as found between 23.5˚ and 66.5˚ of latitude.
Temperate deciduous
forest forest that dominates in temperate areas.
Trees are deciduous i.e. they shed all their leaves during
the winter season (or during drier periods).
Temperate glacier a
glacier in which the ice reaches the
pressure melting
point.
Temperate grasslands
extensive natural grasslands in the continental interiors
of temperate regions.
Temperature inversion
a situation where temperature of air in the lower
troposphere increases with height.
Temperature range the
difference between maximum and minimum temperature. Can be
measured over different timescales, and for absolute
readings or averages.
Tenure the conditions of
occupancy of a piece of land.
Tephra see
pyroclastic cloud.
Terrace an area of flat ground
set into or onto a steep slope.
Terra rossa a soil found on
limestone where silicates have
leached out leaving
oxidized iron-rich deposits which give the soil a
distinctive red colour, hence the name.
Tertiary a period of
geologic time lasting from 65m to 1.6m years ago.
Tertiary sector those
industries providing services, both private and public.
Thermokarst in
periglacial areas, the melting of ground ice causes
subsidence and creates a very uneven surface.
Thermosphere the upper
layer of the atmosphere above 80km from the earths surface.
Extremely hot (up to 1200˚C) due to absorption of radiation
by gases.
The South - see
economically
less developed countries.
Third World - see
economically less developed countries.
Third World debt the huge sums of money owed by
ELDCs to
EMDCs,
banks and institutions such as the IMF. Often debts become
so huge that the country may struggle even to pay the
interest.
Threshold in human geography,
the minimum number of people required to support a good or
service. In physical geography, the shallow area at the
mouth of a
fjord.
Threshold velocity
the velocity required for particles of a certain size to be
taken into transport by an agent of erosion (entrainment).
Throughfall
precipitation
falling through the vegetation cover to the surface. It is
slowed by collisions with leaves and branches but does not
get fully
intercepted by them.
Throughflow the movement of
water through a soil to a river channel.
Tidal energy the energy
involved in tidal movements of water which is available to
be harnessed if those movements can be used to turn
turbines.
Tidal range the difference
in height between low tide and high tide.
Tidal zone the area between
the low water mark and the high water mark.
Tide the periodic rise and fall of
sea level due to the gravitational pull of the sun and moon.
The
tidal range will be determined by the relative
positions of these two bodies which can work with or against
each other.
Till glacial deposits.
Tombolo a sand deposit which
joins an island with a nearby land mass.
Topographical map a
map of surface feature, natural and human, drawn to scale.
Topological map a map
which uses points and straight lines to show relative
positions and linkages e.g. one showing a rail network.
Topset beds layers of
sediment at the landward side of a
delta.
Tor blocks of granite which appear
balanced on one another.
Tornado a localized,
anti-clockwise spiral of wind with extremely violent wind
speed and uplift.
Toxic waste poisonous
by-products of industrial processes which use metals. May be
solid, liquid or gaseous.
Traction the rolling of
load
along the bed of a river channel.
Trade bloc a collection of
countries who agree to make trade between themselves easier
and to maintain barriers to trade with countries outside of
the bloc.
Trade winds easterly winds
which blow from the tropics towards the equator. So named as
they were first identified by sailors who used them to cross
the Atlantic.
Transect a line drawn between
points and then used to investigate changes in surface
features along that line.
Transhipment the transfer
of cargo between ships or between two different modes of
transport.
Translocation the movement
of soil components within the soil.
Transmigration the mass
resettlement of people within a country to alleviate
overcrowding or localized overpopulation.
Transpiration the loss of
water from plants through the stomata in the leaves.
Transnational
corporation one which operates in more than one
country. Traditionally, high value operations such as
headquarters, research and marketing located in
EMDCs while
manufacturing took place in
ELDCs.
Trellised drainage
pattern where the pattern of streams is such that
the
tributaries (or
subsequent streams) to the
main (or
consequent
stream) join at right-angles to
it. The pattern may become more complex with the addition of
obsequent streams. The pattern develops on areas of
alternate bands of resistant and less resistant rock.
Triassic a period of
geologic time lasting from 245m to 208m years ago.
Tributary one river joining
another. Usually the smaller of the two is labelled the
tributary, and the larger is the main channel.
Tricellular model the
basis of the modern understanding of the general circulation
of the
atmosphere as it relates to the
troposphere.
Air rises at the equator due to
convection and is
forced to move to higher latitudes when it reaches the
tropopause. Having cooled it sinks over the tropics and
drags down air adjacent to it. On reaching the surface, the
air is again forced to split; some returning to the equator
and some moving to the mid-latitudes. This warmed air meets
cold polar air at about 60° of latitude and is forced to
rise, again splitting at the tropopause; some returning to
the tropics and some moving over the poles. This circulation
forms three cells known as the Hadley, Ferrel and Polar
respectively.
Trickle down the movement
of wealth from a
core region into the
periphery.
Trophic level in
ecosystems, each level of energy storage which is also a
food supply for the next.
Tropic a line of latitude marking
the most northerly and most southerly overhead paths of the
sun. On June 21st the track is in the north and
is marked by the Tropic of Cancer. On December 21st
the track is in the south and is marked by the Tropic of
Capricorn.
Tropical of the tropics,
commonly relating to areas between them.
Tropical cyclone a
severe low pressure weather system which develops over
tropical maritime areas. A steep
pressure gradient
and the central uplift draws in high speed winds which
spiral towards the central area. Uplift causes cooling to
the
dew point, releasing
latent heat and
maintaining the uplift, drawing in fresh winds. Brings heavy
rainfall to coastal areas. At the end of summer, can develop
into larger, more severe systems such as typhoons and
hurricanes.
Tropical rainforest
a forest biome located approximately 5˚N and S of the
equator. Characterized by high annual rainfall >2000mm and
high average annual temperature >25˚C. Thus, along with the
vegetation being evergreen, it has the highest rate of net
primary productivity of any biome.
More here:
http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/rainforest/rainforest.html
Tropopause a narrow layer of
the atmosphere between the troposphere and the stratosphere.
Varies between altitudes of 8km above the poles to 16km
above the equator. Marks the limit of weather.
Troposphere lower layer of
the atmosphere, from the surface to the
tropopause.
Contains over 50% of the air and is where all weather takes
place.
Trough - 1)
In geology, a trough generally
refers to a linear structural depression that extends
laterally over a distance, while being less steep than a
trench. 2) In
metrology, an elongated region of relatively low atmospheric
pressure, often associated with fronts.
Truncated spur steep
cliff face at the side of a glacial trough where a valley
glacier has removed an interlocking spur. The glacier is
unable to follow the winding course of the original river
and bulldozes straight through.
Tsunami a large wave, or series
of waves, caused when an earthquake causes massive undersea
crust movements and/or collapses which displace the water
above.
Tundra the biome found in the
Arctic circle across North America, Greenland and Europe.
Winters are long and cold and in summer the daytime
temperature rarely exceeds 5˚C. Precipitation is low and
mostly falls as snow. Vegetation is mostly grasses, mosses
and lichens with occasional small trees in more sheltered
areas.
Turbine a rotary motor driven by
a flow of water, steam or wind to produce electrical energy.
Twilight zone in Burgesss
model of urban land use, the second zone, surrounding the
CBD characterized by old factories and slum areas which may
be in transition and experiencing some regeneration.
Typhoon a
tropical cyclone
forming in the western Pacific/South China Sea and posing a
hazard to SE and East Asia.
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