Locations of arid climates.

  BWh

  BWk

Dunes near Ica, Peru

A desert climate (in the Köppen climate classification BWh, BWkl, BWn), also known as an arid climate, is a climate that does not meet the criteria to be classified as a polar climate, and in which precipitation is too low to sustain any vegetation at all, or at most a very scanty scrub.

An area that features this climate usually experiences less than 250 mm (10 inches) per year of precipitation and in some years may experience no precipitation at all. In some instances, an area may experience more than 250 mm of precipitation annually, but is considered a desert climate because the region loses more water via evapotranspiration than falls as precipitation (Tucson, Arizona and Alice Springs, Northern Territory are examples of this).

There fare usually two or three variations of a desert climate: a hot desert climate (BWh), a cold desert climate (BWk) and, sometimes, a mild desert climate (BWn). Furthermore, to delineate "hot desert climates" from "cold desert climates", there are three widely used isotherms: either a mean annual temperature of 18°C, or a mean temperature of 0°C or -3°C in the coldest month, so that a location with a "BS" type climate with the appropriate temperature above whichever isotherm is being used is classified as "hot semi-arid" (BWh), and a location with the appropriate temperature below the given isotherm is classified as "cold semi-arid" (BWk).

To determine whether a location has an arid climate, the precipitation threshold must first be determined. Finding the precipitation threshold (in millimeters) 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 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. If the area's annual precipitation is less than half the threshold, it is classified as a BW (desert climate).^[1]

Hot desert climates[link]

Regions with hot desert climates

Hot desert climates are typically found under the subtropical ridge where there is largely unbroken sunshine for the whole year due to the stable descending air and high pressure. Such areas include the Sahara, the Arabian, Syrian and Kalahari Deserts, large parts of Iran, southern and central Pakistan, northwest India, the southwestern United States, Northern Mexico, and much of Australia.

Hot desert climates feature hot, typically exceptionally hot, periods of the year. In many locations featuring a hot desert climate, maximum temperatures of 40°C to 45°C are not uncommon in summer. 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.

Cold desert climates[link]

Regions with cold desert climates

Cold deserts do get the occasional blanket of snow, like Snake Valley, Utah and Nevada

This variant of the desert climate is somewhat rare outside of Asia. A cold desert climate is typically found in temperate zones, almost always in the rain shadow of high mountains which restrict precipitation from the westerly winds, or in the case of Central Asia, from the monsoon. The Gobi desert in Mongolia is a classic example of a region with a cold desert climate. Though hot in summer, it shares the very cold winters of the rest of Central Asia. The Kyzyl Kum and Taklamakan 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.

Cold desert climates can feature hot (sometimes exceptionally hot) and dry summers, though summers typically are not quite as hot as summers in hot desert climates. Unlike hot desert climates, cold desert climates usually feature cold, sometimes brutally cold, dry winters with temperatures far below the freezing point. Cold deserts are typically found at higher altitudes than hot desert climates, and are usually drier than hot desert climates.

Arctic and Antarctic regions also receive very little precipitation during the year, owing to the exceptionally cold dry air, but they are generally classified as having polar climates.

Mild desert climates[link]

A Dusting of Snow in the Atacama Desert.^[2]

This variant of a desert climate is extremely rare. Mild desert climates are usually found along the west coasts of continents at tropical or near-tropical locations, or at high altitudes in areas that would otherwise feature hot desert climates. In South America, this climate is found adjacent to the Pacific Ocean in sections of the Atacama Desert, especially along the central and southern coast of Peru; Lima, its capital, has a mild desert climate that makes it one of the driest capital cities in the world. In North America, this type of climate can be found along the Pacific coast of the Baja California peninsula. In Africa, this climate is found along sections of coastal Namibia. On the Arabian Peninsula, this type of climate is found in sections of Yemen.

Mild desert climates are characterized by more moderate temperatures than encountered elsewhere at comparable latitudes (usually due to the nearby presence of cold ocean currents) and, in the case of coastal mild deserts, frequent fog and low clouds, despite the fact that these places can rank among the driest on Earth in terms of actual precipitation received. Temperatures are mild throughout the year, usually not subject to any of the temperature extremes typically found in desert climates. Some publications do not have a "mild desert" category; in these documents mild desert climates are sorted into either the hot desert or cold desert classifications.

Regions of varying classification[link]

As stated previously, there are three isotherms used to delineate between hot and cold desert climates. As a result of this, some areas can have climates that are classified as hot or cold depending on the isotherm used.

References[link]

External links[link]

• Desert climate summary
• Desert report/essay

(Clifford) Allan Redin Savory (born September 15, 1935) is a Zimbabwean biologist, farmer, soldier, exile, environmentalist and winner of the Banksia International Award 2003.^[1] and winner of the Buckminster Fuller Award 2010.^[2] He is the originator of the Holistic Management concept.

Political Involvement[link]

Savory was elected into the Rhodesian Parliament representing Matobo constituency in the 1970 election. After resigning from the Rhodesian Front in protest over its racist policies and handling of the war, Savory reformed the defunct Rhodesia Party formerly led by Sir Roy Welensky. Subsequently all moderate white parties united in opposition to Ian Smith in what was known as the National Unifying Force (NUF) led by Savory. When Savory made a public statement that if he had been born a black Rhodesian he would have been a guerilla fighter and urged white Rhodesians to understand why he would feel this, Ian Smith denounced him as a traitor. Because the NUF party would not stand by Savory he relinquished leadership to Tim Gibbs, son of Rhodesia’s last Governor. Savory continued to fight Ian Smith and his policies, in particular opposing the Internal Settlement under Bishop Abel Muzorewa. Finally faced with detention by the Smith government Savory escaped and went into self imposed exile to continue his scientific work as there was no more he felt a white Rhodesian could do to speed an end to the civil war.^[3]

Holistic Management Concept[link]

Savory had begun working on the ancient problem of land degradation (desertification) in 1955 in Northern Rhodesia where he served in the Colonial Service as Provincial Game Officer, Northern and Luapula Provinces. He subsequently continued this work in Southern Rhodesia first as a research officer in the Game Department, then subsequently as an independent scientist and international consultant. When in exile Savory worked from the Cayman Islands into the Americas introducing his new discoveries about both the cause of desertification and how to reverse it using increased numbers of livestock. This work he subsequently wrote up in the book "Holistic Management: A New Decision Making Framework" written with his wife Jody Butterfield and published by Island Press (1989; 1999 2nd edition). In 1992 he co-founded the Africa Center for Holistic Management with his wife, Jody Butterfield, and in 2009 the Savory Institute, which he currently heads. In 2010 Savory and the Africa Center for Holistic Management won The Buckminster Fuller Challenge.^[4]

Today, thousands of families, corporations and businesses are using the holistic management framework developed by Savory to radically improve the quality of their lives and regenerate the resource base that sustains them. This includes conservation projects in the U.S., Africa, Canada and Australia, where large tracts of land are being transformed as desertification is reversed through Holistic Management using livestock and holistic planned grazing as the main agent of change.[2]

See also[link]

• Savory brittleness scale
• Rhodesian general election, 1974

References[link]

Savory, Allan; Jody Butterfield (1998-12-01) [1988]. Holistic Management: A New Framework for Decision Making (2nd ed. ed.). Washington, D.C.: Island Press. ISBN 1-55963-487-1. 

1. ^ Banksia Environmental Foundation. "2003" AWARD
2. ^ Buckminster Fuller Institute
3. ^ "Bring Back the Buffalo!". The Washington Post. May 12, 1997. http://www.washingtonpost.com/wp-srv/style/longterm/books/chap1/bringbac.htm. 
4. ^ John Thackara, "Seed Magazine", June 2010, "[1]", 8-6-10

External links[link]

• Savory Institute
• Africa Centre for Holistic Management

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (April 2009)

Holly Williams (born March 12, 1981) is an American country music artist. She is the daughter of Hank Williams, Jr. and half-sister of country singer Hank Williams III. Williams has released two studio albums: The Ones We Never Knew and Here with Me, in 2004 and 2009 respectively. The latter album has produced two chart singles for her on the Billboard country singles charts with "Keep the Change" and "Mama", which charted to #53 and #55, respectively.

Biography[link]

Raised in Nashville, Tennessee, she is the daughter of Hank Williams, Jr., and the half-sister of Hank Williams III. Holly's mother, Becky, is a native of Mer Rouge, Louisiana, and was married for five years to Hank Williams, Jr.^[1][2] She was born in Cullman, Alabama, and has an elder sister named Hilary. Her parents separated when she was young, although her father took her to many of his shows. At age 17, Holly began playing one of her father's guitars, and soon began writing songs.

Williams graduated from Brentwood Academy and decided to pursue her passion of songwriting and continue playing guitar and piano. She performed hundreds of shows throughout the US and in her hometown and usually toured alone with a guitar and a keyboard. She loved John Prine, Bob Dylan, Tom Waits, Jackson Browne and many other songwriter's known for their way with lyrics, including her grandfather Hank Williams Sr. Eventually she began touring throughout Europe and the United Kingdom and building a loyal fan base there. After the release of her first EP in 2003, she signed with Universal South Records and toured with Billy Bob Thornton, Jewel, Train, Keith Urban, Duncan Sheik, Kasey Chambers and many other artists. Universal South released her debut album, The Ones We Never Knew, in 2004.^[1][2]

In March 2006, Williams was injured in a car crash and canceled a European tour, but she began touring again in November 2006. She signed in 2009 with Mercury Nashville Records. Her second single, "Keep the Change", was released in January and became her first chart single in March. The album's second single, "Mama", was released to radio on May 11, 2009. Williams' second studio album, Here with Me, was released in June 2009. To promote the album, Williams appeared on Late Night with Conan O'Brien, The Late Late Show with Craig Ferguson, Jimmy Kimmel Live!, Chelsea Lately and other television outlets. People Magazine named Williams' 2009 album one of the top ten albums of the year. Williams finished a six week tour in Europe in mid-2010, continued the rest of the year touring with John Hiatt and took time off to write for her third album.

Williams owns H. Audrey, a high end women's boutique located in Nashville.

Discography[link]

Studio albums[link]

Singles[link]

Music videos[link]

References[link]

External links[link]

• Holly Williams official website