A dust storm or sandstorm is a meteorological phenomenon common in arid and semi-arid regions and arises when a gust front passes or when the wind force exceeds the threshold value where loose sand and dust are removed from the dry surface. A meteorological phenomenon is a Weather event which can be explained by the principles of Meteorology. In general terms the Climate of a local or region is said to be arid when it is characterized by a severe lack of available Water, to the extent of hindering A Semi-arid climate or steppe climate generally describes climatic regions that receive low annual Rainfall (250-500 mm or 10-20 in Particles are transported by saltation and suspension, causing soil erosion from one place and deposition in another. For definition and other use disambiguation see Saltation In Geology, saltation (from Latin, saltus, "leap" Erosion is the carrying away or displacement of solids ( Sediment, Soil, rock and other particles usually by the agents of currents such as wind The Sahara and drylands around the Arabian peninsula are the main source of airborne dust, with some contributions from Iran, Pakistan and India into the Arabian Sea, and China's storms deposit dust in the Pacific. The Sahara (الصحراء الكبرى aṣ-ṣaḥrā´ al-kubra, "The Great Desert" is the world's largest hot Desert and the world's second largest The Arabian Peninsula (in Arabic: شبه الجزيرة العربية šibh al-jazīra al-ʻarabīya or جزيرة العرب jazīrat al-ʻarab) For a topic outline on this subject see List of basic Iran topics. Pakistan () officially the Islamic Republic of Pakistan, is a country located in South Asia, Southwest Asia, Middle East and India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country The Arabian Sea ( Arabic: بحر العرب transliterated: Baḥr al-'Arab Sanskrit: सिन्धु सागर transliterated: China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National The Pacific Ocean is the largest of the Earth 's Oceanic divisions It has been argued that recently, poor management of the Earth's drylands, such as neglecting the fallow system, are increasing dust storms from desert margins and changing both the local and global climate, and also impacting local economies. [1]
The term sandstorm is used most often in the context of desert sandstorms, especially in the Sahara, when, in addition to fine particles obscuring visibility, a considerable amount of larger sand particles are blown closer to the surface. A desert is a Landscape or region that receives very little precipitation. The term dust storm is more likely to be used when finer particles are blown long distances, especially when the dust storm affects urban areas.
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Causes
As the force of wind passing over loosely held particles increases, particles of sand first start to vibrate, then to saltate ("leap"). The Dust Bowl, or the dirty thirties, was a period of severe Dust storms causing major ecological and agricultural damage to American and Year 1935 ( MCMXXXV) was a Common year starting on Tuesday (link will display full calendar of the Gregorian calendar. As they repeatedly strike the ground, they loosen smaller particles of dust which then begin to travel in suspension. At wind speeds above that which causes the smallest to suspend, there will be a population of dust grains moving by a range of mechanisms: suspension, saltation and creep. [1]
A recent study finds that the initial saltation of sand particles induces a static electric field by friction. Saltating sand acquires a negative charge relative to the ground which in turn loosens more sand particles which then begin saltating. This process has been found to double the number of particles predicted by previous theory. [2]
Particles become loosely held mainly due to drought or arid conditions, and wind has varied causes. Gust fronts may be produced by the outflow of rain-cooled air from an intense thunderstorm, or they may represent a dry cold front, that is, a cold front that is moving into a dry air mass and is producing no precipitation. A cold front defined as the leading edge of a cooler and drier mass of air In Meteorology, precipitation (also known as one class of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric This is the type of dust storm which was common during the Dustbowl years in the U. The Dust Bowl, or the dirty thirties, was a period of severe Dust storms causing major ecological and agricultural damage to American and S. Following the passage of a dry cold front, convective instability resulting from cooler air riding over heated ground can maintain the dust storm initiated at the front. Convection in the most general terms refers to the movement of molecules within Fluids (i In desert areas, dust and sand storms are most commonly caused by either thunderstorm outflows, or by strong pressure gradients which cause an increase in wind velocity over a wide area. The vertical extent of the dust or sand that is raised is largely determined by the stability of the atmosphere above the ground as well as by the weight of the particulates. In some cases, dust and sand may be confined to a relatively shallow layer by a low-lying temperature inversion. In meteorology an inversion is a deviation from the normal change of an atmospheric property with altitude In other instances, dust (but not sand) may be lifted as high as 20,000 feet (6,100 m) high.
Drought and wind contribute to the emergence of dust storms, as do poor farming and grazing practices by exposing the dust and sand to the wind. A drought is an extended period of months or years when a region notes a deficiency in its water supply Wind is the flow of Air or other Gases that compose an Atmosphere (including but not limited to the Earth's) Agriculture refers to the production of goods through the growing of plants and fungi and the raising of domesticated Animals The study of agriculture
Physical and environmental impacts
A sandstorm can move whole sand dunes. Dust storms can carry large amounts of dust, so much so that the leading edge of one can appear as a solid wall of dust as much as 1. 6 km (1 mile) high. Dust and sand storms which come off the Sahara Desert are locally known as a simoom or simoon (sîmūm, sîmūn). The Sahara (الصحراء الكبرى aṣ-ṣaḥrā´ al-kubra, "The Great Desert" is the world's largest hot Desert and the world's second largest Simoom (سموم samūm; from the root سم s-m-m, "to poison" is a strong dry dust-laden local wind that blows in the Sahara The haboob (həbūb) is a sandstorm prevalent in the region of Sudan around Khartoum. A haboob is a type of intense sandstorm commonly observed in the Sahara desert (typically Sudan) as well as across the Arabian Peninsula throughout Kuwait and in Sudan (officially the Republic of Sudan) ( السودان al-Sūdān is a country in northeastern Africa. Khartoum ( الخرطوم al-Kharṭūm) is the Capital of Sudan and of Khartoum State.
The Sahara desert is a key source of dust storms, particularly the Bodélé Depression[3] and an area covering the confluence of Mauritania, Mali, and Algeria. The Sahara (الصحراء الكبرى aṣ-ṣaḥrā´ al-kubra, "The Great Desert" is the world's largest hot Desert and the world's second largest The Bodélé Depression (also Bodele) located at the southern edge of the Sahara Desert in north central Africa, is the lowest point in Chad Mauritania (موريتانيا Mūrītāniyā officially the Islamic Republic of Mauritania, is a country Mali, officially the Republic of Mali (République du Mali is a Landlocked nation in Western Africa. Algeria ( ar [[Arabic]] الجزائر, Al Jaza'ir ælʤæˈzæːʔir Amazigh: ⴷⵥⴰⵢⴻⵔ Dzayer) officially the People's [4]
Saharan dust storms have increased approximately 10-fold during the half-century since the 1950s, causing topsoil loss in Niger, Chad, northern Nigeria, and Burkino Faso. Niger ( or /ˈnaɪdʒɚ/) officially the Republic of Niger, is a Landlocked country in Western Africa, named after the Niger River. Chad (Tchad تشاد Tshād) officially known as the Republic of Chad, is a Landlocked country in Central Africa. Nigeria, officially named the Federal Republic of Nigeria, is a federal Constitutional republic comprising thirty-six states and one Federal Burkina Faso (bɚˌkiːnəˈfɑːsoʊ burr-KEE-na FAH-soh) also known by its short-form name Burkina, is a Landlocked nation in West Africa In Mauritania there were just two dust storms a year in the early 1960s, but there are about 80 a year today, according to Andrew Goudie, a professor of geography at Oxford University. [5][6] Levels of Saharan dust coming off the east coast of Africa in June (2007) were five times those observed in June 2006, and were the highest observed since at least 1999, which may cool Atlantic waters enough to slightly reduce hurricane activity in late 2007. [7][8]
Economic impact
Dust storms cause soil loss from the dry lands, and worse, they preferentially remove organic matter and the nutrient-rich lightest particles, thereby reducing agricultural productivity. Also the abrasive effect of the storm damages young crop plants. Other effects that may impact the economy are: reduced visibility affecting aircraft and road transportation; reduced sunlight reaching the surface; increased cloud formation increasing the heat blanket effect; high level dust sometimes obscures the sun over Florida; effects on human health of breathing dust.
Dust can also have beneficial effects where it deposits: Central and South American rain forests get most of their mineral nutrients from the Sahara; iron-poor oceans regions get iron; and dust in Hawaii increases plantain growth. The plantain is a crop in the genus Musa and is generally used for cooking in contrast to the soft sweet Banana (which is sometimes called the In northern China as well as the mid-western U. S. , ancient dust storm deposits known as loess are highly fertile soils, but they are also a significant source of contemporary dust storms when soil-securing vegetation is disturbed. Loess is a homogeneous typically non stratified porous Friable,slightly coherent often calcareous fine-grained Silty pale yellow or buff windblown ( aeolian
Extraterrestrial dust storms
See Climate of Mars#Effect of dust storms. The climate of Mars has been an issue of scientific curiosity for centuries due not least to the fact that Mars is the only terrestrial planet whose surface can be directly
Notable dust storms
- A series of dust storms displaced hundreds of thousands of agricultural workers in the central United States and Canada during the Dust Bowl. The United States of America —commonly referred to as the Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page The Dust Bowl, or the dirty thirties, was a period of severe Dust storms causing major ecological and agricultural damage to American and
- A dust storm that occurred near Tucson, Arizona, USA on July 16, 1971 was extensively documented by meteorologists. Events 622 - The beginning of the Islamic calendar. 1054 - Three Roman legates fractured relations between the Western and Year 1971 ( MCMLXXI) was a Common year starting on Friday (link will display full calendar of the 1971 Gregorian calendar.
- On the afternoon of February 8, 1983, a huge dust storm originating in the Mallee region of Victoria, Australia covered the city of Melbourne. Events 421 - Constantius III becomes co- Emperor of the Western Roman Empire. Year 1983 ( MCMLXXXIII) was a Common year starting on Saturday (link displays the 1983 Gregorian calendar) The Mallee is the most northwesterly district in the state of Victoria. For a topic outline on this subject see List of basic Australia topics. Melbourne ( is the second most populous city in Australia, with a Metropolitan area population of approximately 3
- On Saturday afternoon of February 24, 2007, a large dust storm originating in the West Texas area of Amarillo covered much of the North Texas area. Events 303 - Galerius, Roman Emperor, publishes his edict that begins the persecution of Christians in his portion of the Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Texas ( is a state geographically located in the South Central United States and is also known as the Lone Star State. This is an article about a region of Texas For the university in Denton see University of North Texas. Strong winds caused extensive property damage to fences, roof shingles, and some buildings. Property damage (or in the United Kingdom, criminal damage) is damage to or the destruction of public or private Property, caused either by a The DFW Airport was severely affected, causing extensive flight delays into and out of the DFW area. Area residents suffered respiratory problems and allergic reactions, causing many people to visit hospitals. In living organisms a respiratory system functions to allow Gas exchange. Allergy is a disorder of the Immune system often also referred to as Atopy. This event was also marked by relative humidities down to 1 per cent, in one case the juxtaposition of a c. 70°F air temp and dew point of -20°F, in and around of the area affected.
- The multi-year droughts in portions of North America of 1954-56, 1976-78, and 1987-91 were noted for dust storms of the intensity seen in the middle 1930s over some fraction of their coverage and timespan, and more sporadically during the times between. The three multi-year droughts were similar to the 1930s in storms being raised by synoptic scale weather events such as cyclones and cold fronts; otherwise the most common trigger is the outflow from convective activity, known as a haboob. A haboob is a type of intense sandstorm commonly observed in the Sahara desert (typically Sudan) as well as across the Arabian Peninsula throughout Kuwait and in Significant events of the latter variety occurred in Colorado and Kansas in May 2004 with winds to 100 mph, Minnesota and Wisconsin in June 2004 causing significant damage, and the upper Middle West in May 1988, notable for strong electrification and lightning activity and by one estimate reaching 30 000 ft or more. The first and third of this list reached black blizzard intensity, causing total blackout for some period ranging from 90 sec to 10 or more minutes, over some fraction of the ground covered. The 1987-91 drought was especially notable as in the 1930s for the large number of rain of mud events, often generated by dust in suspension and/or carried on upper-level winds.
- Just one of many notable storms in the 1930s, the storm of 9. -11. May 1934 began in the far north-western Great Plains and proceeded east over the nothern tier of states and parts of Canada and was notable for removing the vast majority of the soil deposited since the last Ice Age over some parts of its path.
- In June 2007, a large dust storm struck Karachi Pakistan and areas of the Sindh and lower Balochistan, followed by a series of heavy rainfalls which resulted in a death toll of nearly 200.
Gallery
 Dust plume off the Sahara desert over the northeast Atlantic Ocean. |
 Dust storm in Burkina Faso |
 Martian dust storm |
 Time-lapse composite of the Martian horizon during Sols 1205 (0. Burkina Faso (bɚˌkiːnəˈfɑːsoʊ burr-KEE-na FAH-soh) also known by its short-form name Burkina, is a Landlocked nation in West Africa 94), 1220 (2. 9), 1225 (4. 1), 1233 (3. 8), 1235 (4. 7) shows how much sunlight the July 2007 dust storms blocked; Tau of 4. 7 indicates 99% blocked. credit:NASA/JPL-Caltech/Cornell |
See also
References
- ^ a b Template:Ci te web 'Dust storms are a symptom of poor land management' . Asian Dust (also yellow dust, yellow sand, yellow wind, Korean dust or China dust storms) is a seasonal meteorological phenomenon The Dust Bowl, or the dirty thirties, was a period of severe Dust storms causing major ecological and agricultural damage to American and Fog is a cloud that is in contact with the ground Stratus clouds are usually the only clouds that touch the ground A haboob is a type of intense sandstorm commonly observed in the Sahara desert (typically Sudan) as well as across the Arabian Peninsula throughout Kuwait and in Sirocco, scirocco, jugo or rarely siroc is a Mediterranean Wind that comes from The Saharan Air Layer (SAL is an intensely dry warm and sometimes Dust -laden layer of the Atmosphere which often overlies the cooler more-humid surface air of the Mineral dust is a term used to indicate atmospheric aerosols originated from thesuspension of Minerals constituting the Soil, being composed of various A shamal is a summer northwesterly Wind blowing over Iraq and the Persian Gulf states (including Saudi Arabia and Kuwait) often strong . . 'True deserts are rarely the source of dust storms' . . . 'desert margins are more often the principal source of damaging dust storms' . . . 'Sahara region is the main source of aeolian dust'
- ^ Electric Sand Findings, University of Michigan Jan. 6, 2008
- ^ The Bodélé depression: a single spot in the Sahara that provides most of the mineral dust to the Amazon forest. Ilan Koren et al 2006 Environ. Res. Lett. 1 014005 (5pp) doi:10. 1088/1748-9326/1/1/014005 'about half of the annual dust supply to the Amazon basin is emitted from a single source: the Bodélé depression'
- ^ Saharan Dust: Sources and Trajectories N. J. Middleton, A. S. Goudie Transactions of the Institute of British Geographers, New Series, Vol. 26, No. 2 (2001), pp. 165-181
- ^ ENVIRONMENT: Around the Globe, Farmers Losing Ground Analysis by Lester R. Brown (Jun 27, 2007)
- ^ http://www.earth-policy.org/Books/Seg/PB2ch05_ss3.htm LOSING SOIL Lester R. Brown
- ^ http://www.sciam.com/article.cfm?alias=scientists-examine-africa&chanId=sa003&modsrc=reuters Scientists examine African dust link to hurricanes ScientificAmerican. com August 10, 2007 "These last couple months have been the dustiest summer since 1999, about five times as dusty as last year. Right now ocean temperatures are cooler than average," said Amato Evan, a climate researcher at the University of Wisconsin. "There's a big difference compared to the last two years. "
- ^ Storm Report: Dry air inhibits storms Saharan winds limit formation in warm Gulf Jim Bradshaw, 2007 July 5. Jeff Masters:"Levels of Saharan dust coming off the east coast of Africa in June were five times those observed in June 2006, and were the highest observed since at least 1999"
9. Saharan Dust Has Chilling Effect on North Atlantic http://www.nasa.gov/topics/earth/features/cooling_dust.html
External links
- Slide Show of a Dust Storm in Lubbock, Texas on December 15, 2003
- Dust in the Wind
- Video of a dust storm in Al Asad Iraq, April 27, 2005
- Video of a Sahara Sandstorm
- Photos of dust storms hosted by the Portal to Texas History. Events 533 - Byzantine general Belisarius defeats the Vandals, commanded by King Gelimer, at the Battle of Year 2003 ( MMIII) was a Common year starting on Wednesday of the Gregorian calendar.
- The Bibliography of Aeolian Research
- Storms tear through Texas, neighbor states; Property damage, fires, injuries reported; Arkansas hit hardest
- Dallas dust storm causes LAX delays, cancellations
University of Arizona Dust Model Page
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