Desert climate#Hot desert climates
{{short description|Arid climate subtype in the Köppen climate classification system with very little precipitation}}
{{Use dmy dates|date=September 2024}}
[[File:BW climate.png|thumb|right|upright=1.6|Regions with desert climates
{{legend|#FE0000|BWh (hot desert climates)}}
{{legend|#FE9695|BWk (cold desert climates)}}]]
The desert climate or arid climate (in the Köppen climate classification BWh and BWk) is a dry climate sub-type 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 after the Polar climate.{{cite journal |last=Peel |first=M.C. |last2=Finlayson |first2=B.L. |last3=McMahon |first3=T.A. |title=Updated world map of the Köppen-Geiger climate classification |url=https://www.hydrol-earth-syst-sci.net/11/1633/2007/hess-11-1633-2007.pdf |url-status=live |journal=Hydrology and Earth System Sciences |volume=11 |issue=5 |pages=1633–1644 |year=2007 |access-date=2019-05-20 |archive-url=https://web.archive.org/web/20191202204538/https://www.hydrol-earth-syst-sci.net/11/1633/2007/hess-11-1633-2007.pdf |archive-date=2019-12-02 |bibcode=2007HESS...11.1633P |doi=10.5194/hess-11-1633-2007 |doi-access=free}}
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", a mean annual temperature of {{cvt|18|C|1}} is used as an isotherm so that a location with a BW type climate with the appropriate temperature above this isotherm is classified as "hot arid subtype" (BWh), and a location with the appropriate temperature below the isotherm is classified as "cold arid subtype" (BWk).
Most desert/arid climates receive between {{cvt|25|and|200|mm|0}} of rainfall annually,{{cite book |title=Deserts and Desert Environments |first=Julie J. |last=Laity |publisher=John Wiley & Sons |year=2009 |page=7 |url=https://books.google.com/books?id=wtAbzLLTcwcC&pg=PR5 |isbn=978-1444300741 }}{{Cite web |date=2017-11-01 |title=What is a Desert Climate? |url=https://www.worldatlas.com/articles/what-is-a-desert-climate.html |access-date=2022-04-23 |website=WorldAtlas |language=en-US |archive-date=2021-12-26 |archive-url=https://web.archive.org/web/20211226192324/https://www.worldatlas.com/articles/what-is-a-desert-climate.html |url-status=live }} 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 {{convert|430|mm|in|0|disp=or}}.
{{see also|Aridity index}}
Precipitation
Although no part of Earth is known for certain to be rainless, in the Atacama Desert of northern Chile, the average annual rainfall over 17 years was only {{convert|5|mm}}. Some locations in the Sahara Desert such as Kufra, Libya, record an even drier {{cvt|0.86|mm}} of rainfall annually. The official weather station in Death Valley, United States reports {{cvt|60|mm}} annually, but in 40 months between 1931 and 1934 a total of just {{cvt|16|mm}} of rainfall was 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% of the threshold results in a semi-arid climate.
Hot desert climates
{{redirect|BWh|other uses|Bwh (disambiguation)}}
File:Namibská poušť - panoramio.jpg
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, West Asia, northwestern parts of the Indian Subcontinent, southwestern Africa, interior Australia, the Southwestern United States, northern Mexico, sections of southeastern Spain, the coast of Peru and Chile and parts of the Brazilian sertão. This makes hot deserts present in every continent except Antarctica.
At the time of high sun (summer), scorching, desiccating heat prevails. Hot-month average temperatures are normally between {{cvt|29|and|35|C}}, and midday readings of {{convert|43–46|C|F}} are common. The world's absolute heat records, over {{convert|50|C|F}}, are generally in the hot deserts, where the heat potential can be the highest on the planet. This includes the record of {{convert|56.7|C|F}} in Death Valley, which is currently considered the highest temperature recorded on Earth.{{Cite web |title=Weather - Death Valley National Park |website=U.S. National Park Service |url=https://www.nps.gov/deva/learn/nature/weather-and-climate.htm |access-date=2022-04-23 |language=en |archive-date=2020-10-13 |archive-url=https://web.archive.org/web/20201013021511/https://www.nps.gov/deva/learn/nature/weather-and-climate.htm |url-status=live }} Some deserts 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 {{convert|30|C|F}}, up to nearly {{convert|35|C|F}} in Dallol, Ethiopia. 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, temperatures rarely drop far below freezing under the hot subtype.
File:Koppen-Geiger_Map_v2_BWh_1991–2020.svg
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 West Asia such as the Arabian Desert, or the Syrian Desert; deserts of South Asia such as Dasht-e Lut and Dasht-e Kavir of Iran 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. In Europe, the hot desert climate can only be found on southeastern coast of Spain as well as small inland parts of southeastern, especially parts of the Tabernas Desert.{{cite book |title=Atlas Climático Ibérico |trans-title=Iberian Climate Atlas |year=2011 |url=http://www.aemet.es/documentos/es/conocermas/recursos_en_linea/publicaciones_y_estudios/publicaciones/Atlas-climatologico/Atlas.pdf |doi=10.31978/784-11-002-5 |isbn=978-84-7837-079-5 |lang=es, pt, en |access-date=May 8, 2017|archive-date=November 25, 2020|archive-url=https://web.archive.org/web/20201125004016/http://www.aemet.es/documentos/es/conocermas/recursos_en_linea/publicaciones_y_estudios/publicaciones/Atlas-climatologico/Atlas.pdf|url-status=live}}{{Cite report |year=2022 |title=Evolucion de los climas de Koppen en España: 1951-2020 |url=https://www.aemet.es/documentos/es/conocermas/recursos_en_linea/publicaciones_y_estudios/publicaciones/NT_37_AEMET/NT_37_AEMET.pdf |access-date=2024-01-08 |website=Agencia Estatal de Meteorologia |archive-date=2024-02-13 |archive-url=https://web.archive.org/web/20240213184548/https://www.aemet.es/documentos/es/conocermas/recursos_en_linea/publicaciones_y_estudios/publicaciones/NT_37_AEMET/NT_37_AEMET.pdf |url-status=live |lang=es |first1=Andrés |last1=Chazarra Bernabé |first2=Belinda |last2=Lorenzo Mariño |first3=Ramiro |last3=Romero Fresneda |first4=José Vicente |last4=Moreno García |series=Nota técnica de AEMET |volume=37 |doi=10.31978/666-22-011-4}}
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 almost 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
{{Redirect|BWk||BWK (disambiguation){{!}}BWK}}
File:Koppen-Geiger_Map_v2_BWk_1991–2020.svg
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 northern China and Mongolia is one example of a cold desert. Though hot in the summer, it shares the freezing winters of the rest of Inner Asia. Summers in South America's Atacama Desert are mild, with only slight temperature variations between seasons. Cold desert climates are typically found at higher altitudes than hot desert climates and are usually drier than hot desert climates.
File:Llano de la Jaula, Vallenar (Chili).jpg
File:Camel in Gobi Desert 01.jpg
Cold desert climates are typically located in temperate zones in the 30s and 40s latitudes, usually in the leeward rain shadow of high mountains, restricting 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 significant 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 the Bighorn Basin in Big Horn and Washakie County in Wyoming. The Hautes Plaines, located in the northeastern section of Morocco and in Algeria, is another prominent example of a cold desert climate. In Europe, this climate only occurs in some inland parts of southeastern Spain, such as in Lorca.{{Cite web |title=Valores climatológicos normales |website=Agencia Estatal de Meteorología |url=https://www.aemet.es/es/serviciosclimaticos/datosclimatologicos/valoresclimatologicos |access-date=2024-01-08 |language=es |archive-date=2023-03-26 |archive-url=https://web.archive.org/web/20230326032223/https://www.aemet.es/es/serviciosclimaticos/datosclimatologicos/valoresclimatologicos |url-status=live }}
Polar climate desert areas in the Arctic and Antarctic regions receive very little precipitation during the year owing to the cold, dry air freezing most precipitation. Polar desert climates have desert-like features that occur in cold desert climates, including intermittent streams, hypersaline lakes, and extremely barren terrain in unglaciated areas such as the McMurdo Dry Valleys of Antarctica. These areas are generally classified as having polar climates because they have average summer temperatures below {{convert|10|°C|0}} even if they have some characteristics of extreme non-polar deserts. {{Cite web | url=https://sand-boarding.com/cold-deserts/ | title=Cold deserts: what they are and where can you find them | date=3 January 2022 | access-date=2022-03-03 | archive-date=2024-09-10 | archive-url=https://web.archive.org/web/20240910142007/https://sand-boarding.com/cold-deserts/ | url-status=live }}{{better source needed|date=September 2024}}
Climate charts
=Hot deserts=
|6|19|7
|8|21|0
|12|26|10
|17|32|7
|22|36|1
|25|39|0
|25|39|0
|25|39|0
|24|38|0
|19|29|0
|12|26|1
|7|20|1
|float=left
|clear=left
|source=[http://www.worldweatheronline.com/Sabhah-weather-averages/Sabha/LY.aspx World Weather Online]
}}
{{climate chart|Karachi, Pakistan (bordering on semi arid)
|12.0|26.3|10.6
|14.8|28.7|5.5
|19.4|32.6|3.2
|23.7|35.0|21.1
|27.0|35.7|26.2
|28.6|35.7|44.6
|27.9|33.6|73.1
|26.7|32.5|104.7
|26.0|33.4|44.0
|22.9|35.6|12.7
|17.7|32.6|0.7
|13.4|28.4|5.6
|float=left
|clear=none
|source=NOAA{{cite web |url=https://www.nodc.noaa.gov/archive/arc0216/0253808/2.2/data/0-data/Region-2-WMO-Normals-9120/Pakistan/CSV/Karachi_41780.csv |title=Karachi Climate Normals 1991–2020 |work=World Meteorological Organization Climatological Standard Normals (1991–2020) |publisher=National Oceanic and Atmospheric Administration |access-date=17 September 2023 |archive-date=10 September 2024 |archive-url=https://web.archive.org/web/20240910142006/https://www.nodc.noaa.gov/archive/arc0216/0253808/2.2/data/0-data/Region-2-WMO-Normals-9120/Pakistan/CSV/Karachi_41780.csv |url-status=live }}}}
{{climate chart|Las Vegas, Nevada, United States
|4.7|14.7|14
|6.7|17.2|20
|10.3|21.7|11
|13.8|25.8|5.1
|18.9|31.4|1.8
|24.3|37.4|1.0
|27.8|40.3|9.7
|27.0|39.3|8.1
|22.4|34.9|8.1
|15.3|27.3|8.1
|8.5|19.5|7.6
|4.2|13.8|11
|float=left
|clear=right
|source=NOAA{{cite web
|url = https://w2.weather.gov/climate/xmacis.php?wfo=vef
|title = NowData – NOAA Online Weather Data
|publisher = National Oceanic and Atmospheric Administration
|access-date = October 11, 2021
|archive-date = July 21, 2021
|archive-url = https://web.archive.org/web/20210721064827/https://w2.weather.gov/climate/xmacis.php?wfo=vef
|url-status = dead
}}}}
{{climate chart
|4.7|16.2|24.6
|6.5|19.3|16.6
|10.5|24.5|15.7
|15.7|30.5|16.2
|21.1|37.1|3.3
|24.9|42.9|0
|26.9|44.7|0
|26.2|44.5|0
|22.0|40.3|0.1
|17.2|34.0|7.6
|10.2|23.9|23.6
|6.0|18.0|17.0
|float=left
|clear=left
|source=Climate & Temperature{{cite web |url=http://www.climatetemp.info/iraq/baghdad.html |title=Baghdad Climate Guide to the Average Weather & Temperatures, with Graphs Elucidating Sunshine and Rainfall Data & Information about Wind Speeds & Humidity |access-date=25 December 2011 |publisher=Climate & Temperature |url-status=dead |archive-url=https://web.archive.org/web/20120106135651/http://www.climatetemp.info/iraq/baghdad.html |archive-date=6 January 2012}}{{cite web |url=https://www.weather-atlas.com/en/iraq/baghdad-climate#uv_index |title=Monthly weather forecast and climate for Baghdad, Iraq |access-date=27 April 2020 |archive-date=19 September 2020 |archive-url=https://web.archive.org/web/20200919180124/https://www.weather-atlas.com/en/iraq/baghdad-climate#uv_index |url-status=live}}}}
{{climate chart
|22.2|36.7|14.8
|21.5|35.6|14.3
|18.6|32.2|10.5
|14.4|27.2|14.3
|9.9|22.0|9.4
|6.9|18.4|13.4
|6.3|18.7|4.8
|7.6|21.2|6.6
|11.2|25.8|8.2
|14.2|28.9|13.1
|17.6|32.1|15.4
|20.0|34.6|19.3
|float=left
|clear=none
|source=Bureau of Meteorology (1994–2024 normals, extremes to 1965){{cite web |title=Coober Pedy Climate Statistics (1921–2018) |url=http://www.bom.gov.au/climate/averages/tables/cw_016007_All.shtml |publisher=Bureau of Meteorology |access-date=August 18, 2024}}}}
{{climate chart
|20.5|26.3|0.8
|21.1|27.6|0.4
|20.6|27.1|0.4
|18.7|24.6|0.1
|17.2|21.8|0.3
|16.5|19.8|0.7
|16.0|19.1|1.0
|15.2|18.6|1.5
|15.3|19.0|0.7
|15.9|20.2|0.2
|17.1|21.9|0.1
|18.8|24.0|0.2
|float=left
|clear=right
|source=National Service of Meteorology and Hydrology of Peru (SENAMHI){{cite web |url=https://www.senamhi.gob.pe/?p=normales-estaciones | title= SENAMHI - Normales Estaciones |publisher=SENAMHI | access-date = 13 July 2024 |language=es}}}}
{{clear}}
=Cold deserts=
|-13.1|1.5|4.3
|-9.2|4.2|2.5
|-3.7|9.7|1.5
|1.6|15.3|1.7
|6.2|20.0|0.6
|11.3|24.4|2.9
|15.9|28.5|6.8
|15.1|28.1|6.2
|9.2|23.4|4.4
|0.3|16.7|2.3
|-7.2|10.6|0.7
|-11.7|4.5|1.0
|float=left
|clear=left
|units=metric
{{climate chart|Turpan, Xinjiang, China
|-10.3|-2.3|0.9
|-3.5|7.0|0.5
|5.9|17.9|0.7
|14.2|27.8|0.9
|19.8|33.9|1.0
|24.7|38.8|2.6
|26.5|40.5|2.0
|24.6|39.0|2.0
|18.4|32.6|1.4
|9.1|22.5|1.2
|0.3|10.3|0.6
|-7.6|-0.4|0.9
|float=left
|clear=none
|source=China Meteorological Administration{{cite web |url=http://data.cma.cn/data/weatherBk.html |script-title=zh:中国气象数据网 – WeatherBk Data |publisher=China Meteorological Administration |language=zh-hans |access-date=10 October 2023 |archive-date=5 September 2018 |archive-url=https://web.archive.org/web/20180905194950/http://data.cma.cn/data/weatherBk.html |url-status=live }}{{cite web |url=https://experience.arcgis.com/template/e724038fda394e9d9b7921f10fd1aa55/page/%E7%BA%AF%E8%A1%A8%E6%A0%BC%E7%BB%9F%E8%AE%A1-(%E5%AF%B9%E6%AF%948110%E5%8F%98%E5%8C%96)/?org=UQmaps |script-title=zh:中国气象数据网 |publisher=China Meteorological Administration |language=zh-hans |access-date=10 October 2023 |archive-date=4 April 2023 |archive-url=https://web.archive.org/web/20230404092524/https://experience.arcgis.com/template/e724038fda394e9d9b7921f10fd1aa55/page/%E7%BA%AF%E8%A1%A8%E6%A0%BC%E7%BB%9F%E8%AE%A1-(%E5%AF%B9%E6%AF%948110%E5%8F%98%E5%8C%96)/?org=UQmaps |url-status=live }}}}
{{climate chart
|0.8|13.1|26.0
|2.0|15.3|22.4
|4.8|20.0|13.9
|8.0|25.3|5.6
|12.1|30.9|4.8
|15.9|35.3|0.3
|18.6|37.8|0
|18.6|37.6|0
|15.3|34.6|0.3
|11.0|29.0|6.3
|5.2|20.6|21.4
|1.9|14.8|23.6
|float=left
|clear=right
|source=NOAA (mean temperature 1961–1990, humidity and sun 1970–1990){{cite web
| url = https://www.nodc.noaa.gov/archive/arc0216/0253808/1.1/data/0-data/Region-6-WMO-Normals-9120/Syria/XLS/DamaskusIntAirport_40080.xls
| title = Damascus INTL Climate Normals 1991–2020
| publisher = National Oceanic and Atmospheric Administration
| access-date = 26 April 2017
| archive-date = 19 October 2017
| archive-url = https://web.archive.org/web/20171019065948/ftp://ftp.atdd.noaa.gov/pub/GCOS/WMO-Normals/TABLES/REG_VI/SY/40080.TXT
| url-status = live
}}}}
{{climate chart
|Las Cruces, New Mexico, United States
|-1.3|14.9|12
|0.8|17.8|9.1
|4.0|21.8|6.6
|7.6|25.8|5.6
|12.3|30.6|9.7
|17.6|35.7|17
|20.6|35.3|45
|19.8|34.2|44
|16.2|31.3|36
|9.1|26.4|21
|2.6|19.9|11
|-1.3|14.5|16
|float=left
|clear=left
|source=NOAA{{cite web
|url = https://www.ncei.noaa.gov/access/services/data/v1?dataset=normals-monthly-1991-2020&stations=USC00298535&format=pdf&dataTypes=MLY-TMAX-NORMAL,MLY-TMIN-NORMAL,MLY-TAVG-NORMAL,MLY-PRCP-NORMAL,MLY-SNOW-NORMAL
|publisher = National Oceanic and Atmospheric Administration
|title = U.S. Climate Normals Quick Access – Station: State Univ, NM
|access-date = August 26, 2023}}}}
{{climate chart
|-14.4|-6.8|11
|-13.6|-4.9|13
|-4.4|5.3|16
|5.8|18.2|14
|12.7|26.5|14
|18.4|32.4|12
|20.5|34.2|8
|18.4|32.6|6
|11.2|25.2|4
|3.3|15.8|14
|-4.4|4.0|14
|-11.4|-4.2|13
|float=left
|clear=none
|source=Pogoda.ru.net{{cite web
| url = http://www.pogodaiklimat.ru/climate/35746.htm
| title = Weather and Climate- The Climate of Aral
| publisher = Weather and Climate (Погода и климат)
| language = Russian
| accessdate = 3 January 2022}}}}
{{climate chart|Antofagasta, Chile
|17.4|23.6|0.0
|17.2|23.6|0.0
|16.2|22.6|0.8
|14.6|20.5|0.1
|13.3|18.8|0.2
|12.3|17.3|1.5
|11.7|16.5|0.4
|12.2|16.8|0.8
|12.9|17.4|0.2
|13.9|18.5|0.2
|15.1|20.1|0.1
|16.2|21.8|0.1
|float=left
|clear=right
|source=Dirección Meteorológica de Chile{{cite web
| url = https://climatologia.meteochile.gob.cl/application/historico/datosNormales/230001
| title = Datos Normales y Promedios Históricos Promedios de 30 años o menos
| publisher = Dirección Meteorológica de Chile
| language = es
| access-date = 20 May 2023
| archive-url = https://web.archive.org/web/20230521022007/https://climatologia.meteochile.gob.cl/application/historico/datosNormales/230001
| archive-date = 21 May 2023
| url-status = live
}}}}
{{Clear}}
See also
References
{{reflist}}
External links
{{sister project links|voy=Arid region safety|auto=1}}
- [https://web.archive.org/web/20110304115708/http://www.ace.mmu.ac.uk/eae/climate/Older/Desert_Climate.html Desert climate summary]
- [https://sciencing.com/characteristics-arid-climates-8441465.html Desert climate explanation]
- [http://www.blueplanetbiomes.org/desert.htm Desert report/essay]
{{Koppen}}
{{Authority control}}
Category:Climate of North America