Desert climate

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Regions with desert climates
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BWh (hot desert climates)
BWk (cold desert climates) BW climate.png
Regions with desert climates
   BWh (hot desert climates)
   BWk (cold desert climates)

The desert climate or arid climate (in the Köppen climate classification BWh and BWk), is a climate in which there is a severe excess of evaporation over precipitation. The typically bald, rocky, or sandy surfaces in desert climates are dry and hold little moisture, quickly evaporating the already little rainfall they receive. Covering 14.2% of earth's land area, hot deserts are the second most common type of climate on earth [1] after the polar climate.

Contents

There are two variations of a desert climate according to the Köppen climate classification: a hot desert climate (BWh), and a cold desert climate (BWk). To delineate "hot desert climates" from "cold desert climates", there are three widely used isotherms: most commonly [2] a mean annual temperature of 18 °C (64.4 °F), or sometimes the coldest month's mean temperature of 0 or −3 °C (32.0 or 26.6 °F) in the coldest month, so that a location with a BW type climate with the appropriate temperature above whichever isotherm is being used is classified as "hot arid subtype" (BWh), and a location with the appropriate temperature below the given isotherm is classified as "cold arid subtype" (BWk).

Most desert/arid climates receive between 25 and 200 mm (1 and 8 in) of rainfall annually, [3] [4] although some of the most consistently hot areas of Central Australia, the Sahel and Guajira Peninsula can be, due to extreme potential evapotranspiration, classed as arid with the annual rainfall as high as 430 millimetres or 17 inches.

Precipitation

Although no part of Earth is known for certain to be absolutely rainless ever, in the Atacama Desert of northern Chile, the average annual rainfall over a period of 17 years was only just 5 millimetres (0.20 in). Some locations in the Sahara Desert such as Kufra, Libya record an even drier 0.86 mm (0.034 in) of rainfall annually. The official weather station in Death Valley, United States reports 60 mm (2.4 in) annually, but in a 40-month period between 1931 and 1934 a total of 16 mm (0.63 in) of rainfall was only measured.

To determine whether a location has an arid climate, the precipitation threshold is determined. The precipitation threshold (in millimetres) involves first multiplying the average annual temperature in °C by 20, then adding 280 if 70% or more of the total precipitation is in the high-sun summer half of the year (April through September in the Northern Hemisphere, or October through March in the Southern), or 140 if 30–70% of the total precipitation is received during the applicable period, or 0 if less than 30% of the total precipitation is so received there. If the area's annual precipitation is less than half the threshold (50%), it is classified as a BW (desert climate), while 50-100% the threshold results in a semi-arid climate. [5]

Hot desert climates

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Source: World Weather Online

Hot desert climates (BWh) are typically found under the subtropical ridge in the lower middle latitudes or the subtropics, often between 20° and 33° north and south latitudes. In these locations, stable descending air and high pressure aloft clear clouds and 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 can be 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. [6] Some desert in the tropics 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 under the cold subtype.

Regions with hot desert climates Koppen-Geiger Map BWh present.svg
Regions with hot desert climates

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. [7]

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 makes this desert inhospitable to most species.

Cold desert climates

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Source: [8]
Regions with cold desert climates Koppen-Geiger Map BWk present.svg
Regions with cold desert climates

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 and sporadic in regions with this climate. The Gobi Desert in Mongolia is one great example of 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 leeward rain shadow of high mountains, which restricts precipitation from the westerly winds. An example of this is the Patagonian Desert in Argentina bounded by the Andes ranges to its west. In the case of Central Asia, mountains restrict precipitation from the eastern monsoon. The Kyzyl Kum, Taklamakan and Katpana Desert deserts of Central Asia are other major examples of BWk climates. The Ladakh region, and the city of Leh in the Great Himalayas in India also have a cold desert climate. In North America the cold desert climate occurs in the drier parts of the Great Basin Desert and in the Bighorn Basin in Big Horn and Washakie Counties in Wyoming. The Hautes Plaines, located in the northeastern section of Morocco and in Algeria is another major example of a cold desert climate. The Absheron Peninsula in eastern Azerbaijan is also an example of a cold desert climate.

Arctic and Antarctic regions also receive very little precipitation during the year, owing to the exceptionally cold dry air freezing most precipitation ; however, both of them are generally classified as having polar climates because they have average summer temperatures below 10 °C (50 °F) even if they have such desert-like features as intermittent streams, hypersaline lakes, and extremely barren terrain in unglaciated areas such as the McMurdo Dry Valleys of Antarctica. [9] [10]

See also

Related Research Articles

Climate Statistics of weather conditions in a given region over long periods

Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorological variables that are commonly measured are temperature, humidity, atmospheric pressure, wind, and precipitation. In a broader sense, climate is the state of the components of the climate system, including the atmosphere, the hydrosphere, the cryosphere, the lithosphere and the biosphere and the interactions between them. The climate of a location is affected by its latitude/longitude, terrain, altitude, and nearby water bodies and their currents.

Sahara desert (ecoregion) The ecology of the Sahara desert

The Sahara desert, as defined by the World Wide Fund for Nature (WWF), includes the hyper-arid center of the Sahara, between latitudes 18° N and 30° N. It is one of several desert and xeric shrubland ecoregions that cover the northern portion of the African continent.

Polar climate Climate Classification

The polar climate regions are characterized by a lack of warm summers but with varying winters. Every month in a polar climate has an average temperature of less than 10 °C (50 °F). Regions with polar climate cover more than 20% of the Earth's area. Most of these regions are far from the equator and near the poles, and in this case, winter days are extremely short and summer days are extremely long. A polar climate consists of cool summers and very cold winters, which results in treeless tundra, glaciers, or a permanent or semi-permanent layer of ice.

Mediterranean climate Type of climate

A Mediterranean climate, also called dry summer climate is characterized by dry summers and mild, wet winters. The climate receives its name from the Mediterranean Basin, where this climate type is most common. Mediterranean climate zones are typically located along the western coasts of continents, between roughly 30 and 45 degrees north and south of the equator. The main cause of Mediterranean, or dry summer climate, is the subtropical ridge which extends toward that hemisphere's pole during the summer and migrates toward the equator during the winter due to the seasonal poleward-equatorward variations of temperatures.

Subtropics Geographic and climate zone

The subtropical zones or subtropics are geographical and climate zones located to the north and south of the Tropics. Geographically part of the North and South temperate zones, they cover the latitudes from 23°26′11.0″ (or 23.43638°) to approximately 45° in the Northern and Southern hemispheres. The horse latitudes lie within this range.

Köppen climate classification Climate classification system

The Köppen climate classification is one of the most widely used climate classification systems. It was first published by German-Russian climatologist Wladimir Köppen (1846–1940) in 1884, with several later modifications by Köppen, notably in 1918 and 1936. Later, the climatologist Rudolf Geiger (1894–1981) introduced some changes to the classification system, which is thus sometimes called the Köppen–Geiger climate classification system.

Oceanic climate Climate classification

An oceanic climate, also known as a maritime climate or marine climate, is the Köppen classification of climate typical of west coasts in higher middle latitudes of continents, generally featuring mild summers and cool but not freezing winters, with a relatively narrow annual temperature range and few extremes of temperature. Oceanic climates can be found in both temperate and subtropical areas in both hemispheres, notably in Western Europe, parts of central and Southern Africa, North America, South America, parts of Asia, and as well as parts of Australia and New Zealand.

Semi-arid climate Climate with precipitation below potential evapotranspiration

A semi-arid climate, semi-desert climate, or steppe climate is the climate of a region that receives precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi-arid climates, depending on variables such as temperature, and they give rise to different biomes.

Humid continental climate Category in the Köppen climate classification system

A humid continental climate is a climatic region defined by Russo-German climatologist Wladimir Köppen in 1900, typified by four distinct seasons and large seasonal temperature differences, with warm to hot summers and freezing cold winters. Precipitation is usually distributed throughout the year but often do have dry seasons. The definition of this climate regarding temperature is as follows: the mean temperature of the coldest month must be below 0 °C (32.0 °F) or −3 °C (26.6 °F) depending on the isotherm, and there must be at least four months whose mean temperatures are at or above 10 °C (50 °F). In addition, the location in question must not be semi-arid or arid. The cooler Dfb, Dwb, and Dsb subtypes are also known as hemiboreal climates.

Polar desert Regions of Earth under an ice cap with very low rainfall and no vegetation; type EF under the Köppen classification

Polar deserts are the regions of Earth that fall under an ice cap climate. Despite rainfall totals low enough to normally classify as a desert, polar deserts are distinguished from true deserts by low annual temperatures and evapotranspiration. Most polar deserts are covered in ice sheets, ice fields, or ice caps.

Climate of California Overview of the climate of the U.S. state of California

The climate of California varies widely from hot desert to alpine tundra, depending on latitude, elevation, and proximity to the coast. California's coastal regions, the Sierra Nevada foothills, and much of the Central Valley have a Mediterranean climate, with warmer, drier weather in summer and cooler, wetter weather in winter. The influence of the ocean generally moderates temperature extremes, creating warmer winters and substantially cooler summers in coastal areas.

Holdridge life zones Global bioclimatic scheme for the classification of land areas

The Holdridge life zones system is a global bioclimatic scheme for the classification of land areas. It was first published by Leslie Holdridge in 1947, and updated in 1967. It is a relatively simple system based on few empirical data, giving objective criteria. A basic assumption of the system is that both soil and the climax vegetation can be mapped once the climate is known.

Climate of the United States Varies due to changes in latitude, and a range of geographic features

The climate of the United States varies due to changes in latitude, and a range of geographic features, including mountains and deserts. Generally, on the mainland, the climate of the U.S. becomes warmer the further south one travels, and drier the further west, until one reaches the West Coast.

Climate of Venezuela

The Climate of Venezuela is characterized for being tropical and isothermal as a result of its geographical location near the Equator, but because of the topography and the dominant wind direction, several climatic types occur which can be the same as found in temperate latitudes, and even polar regions. Latitude exerts little influence on the Venezuelan While the coastal cities of Maracaibo, Barcelona, Porlamar and Maiquetia can get extremely hot, cities located at valleys such as Mérida, Caracas, Los Teques and San Cristobal have cooler climates, and the highest towns of Mucuchies and Apartaderos have cold (tundra) climates.

Climate of Spain Overview of the climate of Spain

The climate in Spain varies across continental Spain. Spain is the most climatically diverse country in Europe with 13 different Köppen climates, excluding the Canary Islands, and is within the 10 most climatically diverse countries in the world. The country is dominated by five major climate regions, with the other regions including smaller portions of the country. The Mediterranean environment and location in Europe means that it will experience greater heatwaves and dry weather due to climate change.

Trewartha climate classification

The Trewartha climate classification (TCC) or the Köppen–Trewartha climate classification (KTC) is a climate classification system first published by American geographer Glenn Thomas Trewartha in 1966. It is a modified version of the Köppen–Geiger system, created to answer some of its deficiencies. The Trewartha system attempts to redefine the middle latitudes to be closer to vegetation zoning and genetic climate systems. It was considered a more true or "real world" reflection of the global climate.

Calansho Desert is a desert in eastern Libya in Al Wahat District. It is part of the Sahara and has a hot desert climate (BWh). It is primarily rocky in the north and center, but forms part of the "Great Sand Sea" to the east and contains the Calanshio Sand Sea to the south. As Sarīr is the only settlement in the Sarīr Kalanshiyū. The Sarir oil field is located in the western Sarīr Kalanshiyū.

Wonominta, New South Wales is a remote rural locality and civil parish of Evelyn County in far northwest New South Wales. located at 30°18′40″S 141°05′05″E.

Wygah, New South Wales

The Parish of Wygah, New South Wales located at 30°00′35″S 141°37′52″ is a remote rural locality and civil parish of Evelyn County, New South Wales in far northwest New South Wales.

Parish of Kooltoo, New South Wales is a remote civil parish of Yantara County in far North West New South Wales. The geography of the parish is mostly the flat, arid landscape of the Channel Country. The parish has a Köppen climate classification of BWh.

References

  1. 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 .
  2. "What is a Desert Climate?".
  3. Laity, Julie J. (2009). Deserts and Desert Environments. John Wiley & Sons. p. 7. ISBN   978-1444300741.
  4. "What is a Desert Climate?". WorldAtlas. 2017-11-01. Retrieved 2022-04-23.
  5. 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 .
  6. Valley, Mailing Address: P. O. Box 579 Death; Us, CA 92328 Phone: 760 786-3200 Contact. "Weather - Death Valley National Park (U.S. National Park Service)". www.nps.gov. Retrieved 2022-04-23.
  7. "Atlas.pdf" (PDF). Retrieved 2018-09-01.
  8. "Archived copy". Archived from the original on 2018-02-25. Retrieved 2017-08-16.{{cite web}}: CS1 maint: archived copy as title (link)
  9. "Cold and Polar Deserts" . Retrieved 2022-03-03.
  10. "Why are polar regions not considered deserts? – SidmartinBio". www.sidmartinbio.org. Retrieved 2022-04-23.