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Flashcards in Key Terms Deck (52)
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1

Potential evapotranspiration

is the maximum amount of evaporation and transpiration which could occur if water supply was unlimited.

2

Solar radiation

radiation emitted from the sun

3

Conduction

transfer of heat loss r gain through direct contact

4

Convection

transfer of heat through convective movement of air

5

Terrestrial radiation

radiation emitted from the earth

6

Albedo

the percentage of solar radiation reflected, as opposed to absorbed, by the earths surface

7

Trade Winds

surface prevailing winds which blow fro subtropical high pressure cell towards the Equator.

8

Advection fog

fog created when warm moist air comes into contact with a cold surface

9

Inversion layer

air layer where temperature rises rather than falls with height

10

Inter-tropical convergence zone

an area of rising air, low pressure, converging surface Trade Winds and high temperatures coincident with the Equator.

11

Coriolis

deflection of global winds by the rotation of the earth

12

Polar front

boundary about 50 degrees N and S of the Equator where cool air from the poles meets warm air form the subtropical high pressure cells producing rain.

13

Alveoles

small hollows, 5 - 50 cm in size, occurring in clusters or honeycombs with thin partitions strengthened b case hardening.

14

Tafoni

hollows a few metres across with arch shaped entrances, often developed along lines of weaknesses such as joints and bedding planes.

15

Case hardening

a hard layer of salt encrusted rock formed where salts have been drawn to the surface by capillary action

16

pedestal rock

isolated pillar of rock with an indented profile

17

Inselbergs

upstanding masses of crystalline rock that project above plains in deserts and semi-arid areas

18

Hydrolysis

a weathering process where water reacts with minerals such as feldspars to produce clay minerals

19

Deflation

the entrainment and removal by wind of unconsolidated material.

20

Corrasion

when wind-blown sand abrades rock surfaces

21

Deflation hollows

large enclosed depressions partly created by deflation; for example, the Qattara Depression in the Sahara

22

Salt pan

flat areas encrusted with salt sometimes filled with shallow, saline lakes

23

Desert pavement

surface of stones resting on a finer material such as sand, silt or clay. Known as gibber plains in Australia, and stone pavements in USA. Formed where wind or water selectively removes finer material to leave behind larger stones. Alternative theories suggest that coarse material is brought to the surface by cycles of heating and cooling, freezing and thawing, and wetting and drying.

24

Ventifact

wind polished stones which look like brazil nuts and are a few centimeters in size

25

Yardang

linear ridge of clay, silt or rock sculpted by abrasion and deflation

26

Zeugen

a type of pedestal rock with a resistant cap of rock

27

Suspension

fine sediment carried within the air

28

Saltation

movement of sand grains in a series of hops along the ground

29

Surface creep

rolling or pushing of sediment along the gorund

30

Sand sea

extensive area of sand containing a variety of dune types