El clima desértico o árido (en la clasificación climática de Köppen BWh y BWk ), es un clima en el que hay un exceso de evaporación sobre la precipitación . Las superficies típicamente calvas, rocosas o arenosas en climas desérticos retienen poca humedad y evaporan la poca lluvia que reciben. Los desiertos cálidos, que cubren el 14,2% de la superficie terrestre, son el tipo de clima más común en la tierra [1] después del clima polar .
Aunque no se sabe con certeza que ninguna parte de la Tierra esté absolutamente sin lluvia, en el desierto de Atacama, en el norte de Chile, la precipitación anual promedio durante un período de 17 años fue de solo 5 milímetros (0,20 pulgadas). Algunas ubicaciones en el desierto del Sahara , como Kufra , Libia , registran solo 0,86 mm (0,034 pulgadas) de lluvia al año. La estación meteorológica oficial en Death Valley , Estados Unidos informa 60 mm (2,4 pulgadas) al año, pero en un período de 40 meses entre 1931 y 1934 se midió un total de 16 mm (0,63 pulgadas) de lluvia.
Para determinar si una ubicación tiene un clima árido, se determina el umbral de precipitación. El umbral de precipitación (en milímetros) implica primero multiplicar la temperatura promedio anual en ° C por 20, luego agregar 280 si el 70% o más de la precipitación total se encuentra en la mitad del año con sol alto (de abril a septiembre en el hemisferio norte). , o de octubre a marzo en el sur), o 140 si se recibe del 30 al 70% de la precipitación total durante el período aplicable, o 0 si se recibe menos del 30% de la precipitación total. Si la precipitación anual de la zona es inferior a la mitad del umbral, se clasifica como BW (clima desértico). [2]
Hay dos variaciones de un clima desértico : un clima desértico cálido ( BWh ) y un clima desértico frío ( BWk ). Para delimitar los "climas cálidos del desierto" de los "climas desérticos fríos", hay tres isotermas ampliamente utilizadas : la más común [3] una temperatura media anual de 18 ° C (64,4 ° F) o, a veces, una temperatura media de 0 o −3 ° C (32,0 o 26,6 ° F) en el mes más frío, de modo que un lugar con un clima de tipo BW con la temperatura adecuada por encima de la isoterma que se esté utilizando se clasifique como "árido cálido" ( BWh ), y un lugar con la temperatura adecuada la temperatura por debajo de la isoterma dada se clasifica como "árida fría" ( BWk ).
La mayoría de los climas desérticos / áridos reciben entre 25 y 200 mm (1 y 8 pulgadas) de lluvia al año, [4] aunque algunas de las áreas más cálidas de la península del Sahel y la Guajira pueden deberse a una evapotranspiración potencial extrema clasificada como árida con precipitaciones de hasta 430 milímetros o 17 pulgadas.
Climas cálidos del desierto [ editar ]
| Sabha | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Carta climática ( explicación ) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Hot desert climates (BWh) are typically found under the subtropical ridge in the lower middle latitudes, often between 20° and 33° north and south latitude. In these locations, stable descending air and high pressure aloft create hot, arid conditions with intense sunshine. Hot desert climates are found across vast areas of North Africa, the Middle East, northwestern parts of the Indian Subcontinent, interior Australia, and smaller areas of the Southwestern United States, and Chile. This makes hot deserts present in every continent except Antarctica, with Almería in Southern Spain also having this climate.
At the time of high sun (summer), scorching, desiccating heat prevails. Hot-month average temperatures are normally between 29 and 35 °C (84 and 95 °F), and midday readings of 43–46 °C (109–115 °F) are common. The world absolute heat records, over 50 °C (122 °F), are generally in the hot deserts, where the heat potential is the highest on the planet. This includes the record of 56.7 °C (134.1 °F) in Death Valley, which is currently considered the highest temperature recorded on Earth. Some desert locations consistently experience very high temperatures all year long, even during wintertime. These locations feature some of the highest annual average temperatures recorded on Earth, exceeding 30 °C (86 °F). This last feature is seen in sections of Africa and Arabia. During colder periods of the year, night-time temperatures can drop to freezing or below due to the exceptional radiation loss under the clear skies. However, very rarely do temperatures drop far below freezing.
Hot desert climates can be found in the deserts of North Africa such as the wide Sahara Desert, the Libyan Desert or the Nubian Desert; deserts of the Horn of Africa such as the Danakil Desert or the Grand Bara Desert; deserts of Southern Africa such as the Namib Desert or the Kalahari Desert; deserts of the Middle East such as the Arabian Desert, the Syrian Desert or the Lut Desert; deserts of South Asia such as Dasht-e Kavir or the Thar Desert of India and Pakistan; deserts of the United States and Mexico such as the Mojave Desert, the Sonoran Desert or the Chihuahuan Desert; deserts of Australia such as the Simpson Desert or the Great Victoria Desert and many other regions.[5]
Hot deserts are lands of extremes: most of them are among the hottest, the driest and the sunniest places on Earth because of nearly constant high pressure; the nearly permanent removal of low pressure systems, dynamic fronts and atmospheric disturbances; sinking air motion; dry atmosphere near the surface and aloft; the exacerbated exposure to the sun where solar angles are always high.
Cold desert climates[edit]
| Leh | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Climate chart (explanation) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Cold desert climates (BWk) usually feature hot (or warm in a few instances), dry summers, though summers are not typically as hot as hot desert climates. Unlike hot desert climates, cold desert climates tend to feature cold, dry winters. Snow tends to be rare in regions with this climate. The Gobi Desert in Mongolia is a classic example for cold deserts. Though hot in the summer, it shares the very cold winters of the rest of Central Asia. Cold desert climates are typically found at higher altitudes than hot desert climates and are usually drier than hot desert climates.
Cold desert climates are typically located in temperate zones, usually in the rain shadow of high mountains, which restrict precipitation from the westerly winds. An example of this is the Patagonian Desert in Argentina bounded by the Andes to its west. In the case of Central Asia, mountains restrict precipitation from the monsoon. The Kyzyl Kum, Taklamakan and Katpana Desert deserts of Central Asia and the drier portions of the Great Basin Desert of the western United States are other major examples of BWk climates. The Ladakh region, and the city of Leh in the Great Himalayas in India, also has a cold desert climate. The Hautes Plaines is another major example of cold desert climates, located in the northeastern section of Morocco and in Algeria. This is also found in Europe, primarily in Bardenas Reales near Tudela, Navarre, Spain and high altitude parts of the Tabernas Desert in Almería, Spain.
Arctic and Antarctic regions also receive very little precipitation during the year, owing to the exceptionally cold dry air; however, both of them are generally classified as having polar climates because they have average summer temperatures below 10 °C (50 °F).
See also[edit]
- List of deserts
References[edit]
- ^ Peel, M. C.; B. L. Finlayson; T. A. McMahon (2007). "Updated world map of the Köppen-Geiger climate classification" (PDF). Hydrology and Earth System Sciences. 11 (5): 1633–1644. Bibcode:2007HESS...11.1633P. doi:10.5194/hess-11-1633-2007.
- ^ Peel, M. C.; B. L. Finlayson; T. A. McMahon (2007). "Updated world map of the Köppen-Geiger climate classification" (PDF). Hydrology and Earth System Sciences. 11: 1633–1644. Bibcode:2007HESS...11.1633P. doi:10.5194/hess-11-1633-2007.
- ^ "What is a Desert Climate?".
- ^ Laity, Julie J. (2009). Deserts and Desert Environments. John Wiley & Sons. p. 7. ISBN 978-1444300741.
- ^ "Atlas.pdf" (PDF). Retrieved 2018-09-01.
- ^ "Archived copy". Archived from the original on 2018-02-25. Retrieved 2017-08-16.CS1 maint: archived copy as title (link)
External links[edit]
 | Wikivoyage has a travel guide for Arid region safety. |
- Desert climate summary
- Desert report/essay
