Arid


Arid

A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life. As a result, environments subject to arid climates tend to lack vegetation and are called xeric or desertic.

Contents

Concepts

The expression 'available water' refers to water in the soil in excess to the wilting point. The air over a hot desert may actually contain substantial amounts of water vapor but that water may not be generally accessible to plants, except for very specialized organisms (such as some species of lichen). 'Lack of water' refers to use by plants. The water that is actually present in the environment may be sufficient for some species or usages (such as climax vegetation), and grossly insufficient for others. Aridity, the characteristic nature of an arid climate, may thus depend on the use of the land. Regards to the presence of life, what is more important than the degree of rainfall is the fraction of precipitation that is not quickly lost through evaporation or runoff. Attempts to quantitatively describe the degree of aridity of a place has often led to the development of aridity indexes. There is no universal agreement on the precise boundaries between classes such as 'hyper-arid', 'arid', 'semi-arid', etc.

Geographical distribution

Although different classification schemes and maps differ in their details, there is a general agreement about the fact that large areas of the Earth are arid. These include the hot deserts located broadly in sub-tropical regions, where the accumulation of water is largely prevented by either low precipitations, or high evaporation, or both, as well as cold deserts near the poles, where water may be permanently locked in solid forms (snow and ice). Other arid regions include areas located in the rain shadows of major mountain ranges or along coastal regions affected by significant upwelling (such as the Atacama Desert).

Change over time

The distribution of aridity observed at any one point in time is largely the result of the general circulation of the atmosphere. The latter does change significantly over time through climate change. In addition, changes in land use can result in greater demands on soil water and induce a higher degree of aridity. See aridification.

See also

References

  • Griffiths, J. F. (1985) 'Climatology', Chapter 2 in Handbook of Applied Meteorology, Edited by David D. Houghton, John Wiley and Sons, ISBN 0-471-08404-2.
  • Durrenberger, R. W. (1987) 'Arid Climates', article in The Encyclopedia of Climatology, p. 92-101, Edited by J. E. Oliver and R. W. Fairbridge, Van Nostrand Reinhold Company, New York, ISBN 0-87933-009-0.
  • Stadler, S. J (1987) 'Aridity Indexes', article in The Encyclopedia of Climatology, p. 102-107, Edited by J. E. Oliver and R. W. Fairbridge, Van Nostrand Reinhold Company, New York, ISBN 0-87933-009-0.

Wikimedia Foundation. 2010.

Synonyms:

Look at other dictionaries:

  • arid — ARÍD, Ă, arizi, de, adj. (Despre soluri, teritorii etc.) Uscat2; neroditor, sterp. ♢ fig. Text arid. – Din fr. aride, lat. aridus. Trimis de romac, 11.02.2004. Sursa: DEX 98  Arid ≠ fertil, mănos, roditor, rodnic Trimis de siveco, 03.08.2004.… …   Dicționar Român

  • Arid — Жанр арт рок Альтернативный рок инди рок поп рок Годы 1996 настоящее время …   Википедия

  • Arid — Arid, Groupe de rock indépendant belge, formé du chanteur / guitariste Jasper Steverlinck, du guitariste David Du Pré, du bassiste Filip Ros, et du batteur Steven Van Havere. Ce groupe est souvent comparé à Jeff Buckley, du fait de la voix haut… …   Wikipédia en Français

  • Arid — heißen: arides Klima Arid (Band), belgische Rockband „Arid“ Diese Seite ist eine Begriffsklärung zur Unterscheidung mehrerer mit demselben Wort bezeichneter Begriffe …   Deutsch Wikipedia

  • Arid — Ar id, a. [L. aridus, fr. arere to be dry: cf. F. aride.] Exhausted of moisture; parched with heat; dry; barren. An arid waste. Thomson. [1913 Webster] …   The Collaborative International Dictionary of English

  • arid — (adj.) 1650s, dry, parched, from Fr. aride (15c.) or directly from L. aridus dry, arid, parched, from arere to be dry, from PIE root *as to burn, glow (see ASH (Cf. ash) (1)). Figurative sense of uninteresting is from 1827. Related: Aridly …   Etymology dictionary

  • arid — [adj1] dry barren, bone dry, desert, dry as a bone, dry as dust, dusty, moistureless, parched, thirsty, waterless; concept 603 Ant. damp, humid, moist, wet arid [adj2] uninterested, spiritless boring, colorless, drab, dreary, dry, dull, flat,… …   New thesaurus

  • Arid — (v. lat.), dürre, trocken …   Pierer's Universal-Lexikon

  • Arīd — (franz.), dürr, trocken; Aridität, Trockenheit. Dürre …   Meyers Großes Konversations-Lexikon

  • Arid — Arīd (lat.), dürr, trocken; Aridität, Dürre …   Kleines Konversations-Lexikon

  • Arid — Arid, dürr, trocken; Aridität, Dürre, Trockenheit …   Herders Conversations-Lexikon


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.