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54-849: Dust storms from the Bodélé Depression occur on average about 100 days per year, one typical example being the massive dust storms that swept over West Africa and the Cape Verde Islands in February 2004. As the wind sweeps between the Tibesti and the Ennedi Mountains in Northern Chad , it is channeled across the depression. The dry bowl that forms the depression is marked by a series of ephemeral lakes , many of which were last filled during wetter periods of

108-501: A gust front or other strong wind blows loose sand and dirt from a dry surface. Fine particles are transported by saltation and suspension, a process that moves soil from one place and deposits it in another. The arid regions of North Africa , the Middle East , Central Asia and China are the main terrestrial sources of airborne dust. It has been argued that poor management of Earth's drylands , such as neglecting

162-541: A center for resort and travel destinations in the United States. New York City is the most populous city in the country and a major world financial center. Seventy-one of the world's Fortune 500 companies have their corporate headquarters in New York City, while Midtown Manhattan , with 400 million square feet of office space in 2018, is the largest central business district in the world. Washington, D.C.

216-431: A considerable amount of larger sand particles are blown closer to the surface. 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 . As the force of dust passing over loosely held particles increases, particles of sand first start to vibrate, then to move across the surface in a process called saltation . As they repeatedly strike

270-590: A feature now called the Bodélé Low Level Jet. In the reanalysis data sets such as ERA-40 , the wind shows up as a clear wind speed maximum at about 900 hPa (or roughly 1 km above the surface) near 18 N and 19 E. This jet maximum coincides with the exit gap of the North-easterlies between the Tibesti mountains and the Ennedi massif, which lie 2600 m and 1000 m above the flat terrain in

324-505: A major health hazard. 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. Wildfires can lead to dust storms as well. One poor farming practice which contributes to dust storms is dryland farming . Particularly poor dryland farming techniques are intensive tillage or not having established crops or cover crops when storms strike at particularly vulnerable times prior to revegetation . In

378-570: A marked seasonal cycle. It is active in the October–March period and relatively inactive from June–August. This timing closely matches the seasonality of dust emission from the Bodélé. Individual dust storms in the Bodélé were also shown in this research to coincide with a major strengthening of the Bodélé Low Level Jet which, in turn, is associated with the ridging of the Libyan High, a feature of

432-411: 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 theories. Particles become loosely held mainly due to a prolonged drought or arid conditions, and high wind speeds. Gust fronts may be produced by the outflow of rain-cooled air from an intense thunderstorm . Or,

486-422: A semi-arid climate, these practices increase susceptibility to dust storms. However, soil conservation practices may be implemented to control wind erosion . A sandstorm can transport and carry large volumes of sand unexpectedly. Dust storms can carry large amounts of dust, with the leading edge being composed of a wall of thick dust as much as 1.6 km (5,200 ft) high. Dust and sand storms which come off

540-464: A system of processes operating over paleo timescales. The largest town associated with the Bodélé dust source is Faya-Largeau ( 17°55′00″N 19°7′00″E  /  17.91667°N 19.11667°E  / 17.91667; 19.11667 ), located just to the northeast of the depression. Dust storm A dust storm , also called a sandstorm , is a meteorological phenomenon common in arid and semi-arid regions. Dust storms arise when

594-443: A warm temperate climate ( Cfa Köppen/ Do Trewartha) with long and hot summers with at least one month over 22°C (71.6°F), cool winters with all months over freezing, and six to seven months above 50°F. Although winter precipitation is more likely to fall as rain than as snow, occasional heavy snow is possible. The area from the southern Delmarva Peninsula , southeast Virginia, and central North Carolina south to central Florida

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648-416: 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 other instances, dust (but not sand) may be lifted as high as 6,000 m (20,000 ft). Dust storms are

702-535: A year since 2007, according to English geographer Andrew Goudie , professor at the University of Oxford . 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 have cooled Atlantic waters enough to slightly reduce hurricane activity in late 2007. Dust storms have also been shown to increase

756-535: Is frequently emitted into the Mediterranean atmosphere and transported by the winds sometimes as far north as central Europe and Great Britain. Saharan dust storms have increased approximately 10-fold during the half-century since the 1950s, causing topsoil loss in Niger , Chad , northern Nigeria , and Burkina Faso . In Mauritania there were just two dust storms a year in the early 1960s; there are about 80

810-547: Is humid subtropical ( Cfa/Cf ), with hot and rainy summers, mild and drier winters, and eight to twelve months above 50°F. Urban heat island exclaves of this zone are found north of this area in Baltimore and Washington, D.C. The region of Florida from the south-central region of the state south to the Florida Keys has a tropical climate ( Af/Aw/Ar ) that is usually frost-free and warm to hot all year, and all of

864-901: Is increased when there are great temperature variations like those seen at the equator during the Martian summer. East coast of the United States The East Coast of the United States , also known as the Eastern Seaboard , the Atlantic Coast , and the Atlantic Seaboard , is the region encompassing the coastline where the Eastern United States meets the Atlantic Ocean . The Thirteen Colonies , which formed

918-528: Is more likely to fall as rain than as snow, occasional heavy snow is possible. The East Coast, with the exception of eastern Maine, is a low-relief, passive margin coast. It has been shaped by the Pleistocene glaciation in the far northern areas in New England, with offshore islands such as Nantucket , Martha's Vineyard , Block Island , and Fishers Island . From northern New Jersey southward,

972-429: Is the federal capital and political nerve center of the United States. Many organizations such as defense contractors, civilian contractors, nonprofit organizations, lobbying firms, trade unions, industry trade groups and professional associations have their headquarters in or near Washington, D.C., in order to be close to the federal government . Miami is one of the top domestic and international travel destinations in

1026-652: The Holocene . Diatoms from these fresh water lakes, once part of the prehistoric Mega-Lake Chad, now make up the surface of the depression and are the source material for the dust, which, carried across the Atlantic Ocean, is an important source of nutrient minerals for the Amazon rainforest . As the Sahara dried out over the last few thousand years , Mega-Lake Chad receded to the current position of Lake Chad in

1080-701: The Potomac River , respectively, both of which are tidal arms of the Atlantic Ocean. The original Thirteen Colonies of Great Britain in North America all lay along the East Coast. Two additional U.S. states on the East Coast were not among the original Thirteen Colonies: Maine became part of the English Colony of Massachusetts in 1677 and Florida was held by the British from

1134-529: The Sahara Desert are locally known as a simoom or simoon (sîmūm, sîmūn). The haboob (həbūb) is a sandstorm prevalent in the region of Sudan around Khartoum , with occurrences being most common in the summer. The Sahara desert is a key source of dust storms, particularly the Bodélé Depression and an area covering the confluence of Mauritania , Mali , and Algeria . Sahara dust

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1188-425: The fallow system, are increasing the size and frequency of dust storms from desert margins and changing both the local and global climate, as well as impacting local economies. The term sandstorm is used most often in the context of desert dust storms, especially in the Sahara Desert , or places where sand is a more prevalent soil type than dirt or rock, when, in addition to fine particles obscuring visibility,

1242-617: The 12 months of the year average above 18 °C (64.4 °F). This region of Florida is the only tropical climate in the continental U.S. Although landfalls are rare, the Eastern Seaboard is susceptible to hurricanes in the Atlantic hurricane season, officially running from June 1 to November 30, although hurricanes can occur before or after these dates. Hurricanes Hazel , Hugo , Bob , Isabel , Irene , and Sandy , and most recently Florence , Isaias , Henri , and Ida are some of

1296-473: The Bodélé Low Level Jet flows over a near-surface inversion, but quickly mixes down to the surface a few hours after sunrise once the intense surface heating induces turbulence in the lowest layers. Dust from the Bodélé may be seen as a simple coincidence of two key requirements for deflation: strong surface winds and erodible sediment. But recent research has argued that long-term links exist between topography, wind, deflation and dust, and that topography acts as

1350-565: The Djourab Desert of Chad, respectively. The effect of the Tibesti massif is clearly evident in creating a split in the low-level easterly flow north and south of these mountains. While the jet feature is pronounced over the Bodélé, it is absent from other longitudes over west Africa along 18 N. It is therefore a feature which uniquely overlies the greater Bodélé region, downwind of the mountains of Chad. The Bodélé Low Level Jet undergoes

1404-779: The East Coast is connected from the Annisquam River in Gloucester, Massachusetts to Miami, Florida , by the Intracoastal Waterway , also known as the East Coast Canal, which was completed in 1912. Amtrak's Downeaster and Northeast Regional offer the main passenger rail service on the Seaboard. The Acela Express offers the only high-speed rail passenger service in the Americas, by

1458-614: The Sahara; iron-poor ocean regions get iron; and dust in Hawaii increases plantain growth. 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. Iranian cities existence are challenged by dust storms. Dust storms are not limited to Earth and have also been known to form on Mars . These dust storms can extend over larger areas than those on Earth, sometimes encircling

1512-518: The United States in 1776 were located on this coast, and it has played an important role in the development of the United States. The region is generally understood to include the U.S. states that border the Atlantic Ocean: Connecticut , Delaware , Florida , Georgia , Maine , Maryland , Massachusetts , New Hampshire , New Jersey , New York , North Carolina , Rhode Island , South Carolina , and Virginia , as well as

1566-415: The United States. Miami is the warmest major city in the continental United States in winter, which contributes to it being a major tourism hub for international visitors. Miami has one of the largest concentrations of international banks in the United States, and the third-largest skyline in the U.S. with over 439 high-rises, 68 of which exceed 490 ft (149 m). Port of Miami is the busiest cruise port in

1620-526: The circulatory system. Dust pneumonia is the result of large amounts of dust being inhaled. Prolonged and unprotected exposure of the respiratory system in a dust storm can also cause silicosis , which, if left untreated, will lead to asphyxiation ; silicosis is an incurable condition that may also lead to lung cancer . There is also the danger of keratoconjunctivitis sicca ("dry eyes") which, in severe cases without immediate and proper treatment, can lead to blindness . Dust storms cause soil loss from

1674-460: The coastal plain broadens southwards, separated from the Piedmont region by the Atlantic Seaboard fall line of the East Coast rivers, often marking the head of navigation and prominent sites of cities. The coastal areas from Long Island south to Florida are often made up of barrier islands that front the coastal areas, with the long stretches of sandy beaches. Many of the larger capes along

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1728-465: The coastline lies along the Atlantic Ocean . The 14 states that have a shoreline on the Atlantic Ocean are (from north to south): Maine , New Hampshire , Massachusetts , Rhode Island , Connecticut , New York , New Jersey , Delaware , Maryland , Virginia , North Carolina , South Carolina , Georgia , and Florida . Pennsylvania and Washington, D.C. border the Delaware River and

1782-439: The controlling agent ensuring the long term maintenance of this source. The spatial co-location of strong winds and dust is not simply fortuitous, but results from a set of processes. Specifically: Wind conditions which deflate the erodible sediment now may have created the depression necessary for generating the erodible diatomite in the past. Instead of a simple coincidence of nature, the world's largest dust source results from

1836-611: The depression produces an average of 700,000 tonnes of dust each day (Todd et al., 2007). Research published in the 25 March 2004 edition of Geophysical Research Letters , which used images taken by the Moderate Resolution Imaging Spectroradiometer (MODIS), aboard NASA 's Terra and Aqua satellites, indicated that storms move across the Bodélé Depression at about 47 km/h (29 mi/h)—two times faster than previously believed. The research also found that winds have to whip across

1890-450: The drylands, 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. Dust storms also reduce visibility, affecting aircraft and road transportation. Dust can also have beneficial effects where it deposits: Central and South American rainforests get significant quantities of mineral nutrients from

1944-532: The end of the French and Indian War until 1781 and was part of New Spain until 1821. In present-day Florida, Spanish explorer Juan Ponce de León made the first textual records of the state during his 1513 voyage. The state was initially named for Ponce de Ponce de León, who called the peninsula La Pascua Florida in recognition of the verdant landscape and because it was the Easter season. Delaware Colony and

1998-513: The federal capital of Washington, D.C. , and non-coastline states: Pennsylvania , Vermont , and West Virginia . The place name East Coast derives from the idea that the contiguous 48 states are defined by two major coastlines, one at the western edge and one on the eastern edge. Other terms for referring to this area include the Eastern Seaboard , which is another term for coastline, Atlantic Coast, and Atlantic Seaboard because

2052-522: The first spot in the United States that immigrants arrived and the close proximity of Europe , the Caribbean , and Latin America , the East Coast is home to a diverse population and home to multi-cultures when compared to the rest of the U.S. From the strong Latin culture in southern Florida , to the 200-year-old Gullah culture of the low country coastal islands of Georgia and South Carolina , to

2106-420: The ground, they loosen and break off 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 . A study from 2008 finds that the initial saltation of sand particles induces a static electric field by friction. Saltating sand acquires

2160-417: The largest city and the largest metropolitan area on the East Coast. The East Coast is the most populated coastal area in the United States. Hartford The primary Interstate Highway along the East Coast is Interstate 95 , completed in 2018, which replaced the historic U.S. Route 1 ( Atlantic Highway ), the original federal highway that traversed all East Coast states, except Delaware . By water,

2214-1441: The lenient US definition of high speed rail. Between New York and Boston the Acela Express has up to a 54% share of the combined train and air passenger market. Some of the largest airports in the United States are located along the East Coast of the United States, such as John F. Kennedy International Airport in Queens , New York City , Logan International Airport in Boston , Newark Liberty Airport in Newark, New Jersey , Philadelphia International Airport in Philadelphia , Baltimore–Washington International Airport near Baltimore , Dulles International Airport near Washington, D.C. , Hartsfield–Jackson International Airport in Atlanta , Miami International Airport in Miami , Charlotte Douglas International Airport in Charlotte, North Carolina , Tampa International Airport in Tampa , and Orlando International Airport in Orlando, Florida . As

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2268-463: The lower East Coast are in fact barrier islands, like the Outer Banks of North Carolina and Cape Canaveral , Florida. The Florida Keys are made up of limestone coral and provide the only coral reefs on the U.S. mainland. In 2010, the population of the states that have shoreline on the East Coast was estimated at 112,642,503 (about 36% of the country's total population). New York City is both

2322-538: The many historic cities in the Mid-Atlantic , where a strong English, German, Italian, Irish, and French culture are present, the East Coast is significantly more diverse than the rest of the United States. Numerous Chinatowns in New York City , and Little Havana in Miami , are examples of such cultural centers in the bigger cities. The East Coast is home to much of the political and financial power and

2376-686: The monthly mean temperature of the coldest month (January) and the number of months averaging above 50 °F (10 °C), respectively. The region from northern Maine and Upstate New York south to almost all of Connecticut, most of northern New Jersey (except for areas close enough to New York City ), most of Pennsylvania, and western Maryland has a humid continental climate ( Dfa/Dfb/Dc ), with warm-to-hot summers, cold and snowy winters with at least one month averaging below freezing, and four to seven months with mean temperatures warmer than 50 °F. The area from Martha's Vineyard and extreme SW Rhode Island to southern Delaware and western North Carolina has

2430-465: The more significant storms to have affected the region. The least common climate on the East Coast is the oceanic ( Cfb/Do ), which is only found on Block Island , Nantucket , and the Outer Cape and Chatham on Cape Cod , and in areas of the southern Appalachian Mountains . This zone has all monthly averages between 0 and 22 °C and six to seven months above 50 °F. Although winter precipitation

2484-403: The planet, with wind speeds as high as 25 m/s (60 mph). However, given Mars' much lower atmospheric pressure (roughly 1% that of Earth's), the intensity of Mars storms could never reach the hurricane-force winds experienced on Earth. Martian dust storms are formed when solar heating warms the Martian atmosphere and causes the air to move, lifting dust off the ground. The chance for storms

2538-742: The provinces of New Jersey , New York , and Pennsylvania had been colonized by the Dutch as New Netherland until they were ceded to the British in the mid- to late-17th century. Until 1791, Vermont was an independent nation as the Vermont Republic . Three basic climate regions occur on the East Coast according to the Köppen climate classification and four occur according to the Trewartha climate classification from north to south based on

2592-412: The radiation budget in the Bodélé Depression for the first time. This work coincided with a major dust emission event during which the Bodélé Low Level Jet sustained surface wind speeds of around 16 m/s. The core of the Bodélé Low Level Jet was also mapped for the first time from the wind data, and was shown to undergo a very marked diurnal cycle with peak winds occurring mid morning. During night time,

2646-562: The region at a minimum of 36 km/h (22 mi/h), to kick up a dust storm . The pattern of air flow is so common that the winds have scoured a straight path in the ground, marking their southwesterly flow. Complementary research published in Geophysical Research Letters by Richard Washington from the University of Oxford and Martin Todd from the University of Sussex has shown that these strong winds are part of

2700-427: The south-west corner of Chad. As the waters receded, the silts and sediments resting on the lakebed, which included fossilized diatoms , were left to dry in the scorching sun, forming a layer of fine dust. These small grains of sediment are swept up by the strong wind gusts that occasionally blow over the region. Once heaved aloft, the Bodélé dust can be carried for hundreds or even thousands of kilometers. In winter,

2754-532: The spread of disease across the globe. Bacteria and fungus spores in the ground are blown into the atmosphere by the storms with the minute particles and interact with urban air pollution. Short-term effects of exposure to desert dust include immediate increased symptoms and worsening of the lung function in individuals with asthma , increased mortality and morbidity from long-transported dust from both Saharan and Asian dust storms suggesting that long-transported dust storm particles adversely affects

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2808-535: The subtropical High Pressure belt. The same researchers who in 2004 more accurately determined the speed of wind through the depression also published in 2006 work showing that more than half of the dust needed for fertilizing the Amazon Rainforest is provided by the Bodélé depression, which deposits up to 50 million tonnes in South America per year. The research also shows that, contrary to what

2862-631: The wind gusts may be produced by a dry cold front : that is, a cold front that is moving into a dry air mass and is producing no precipitation —the type of dust storm which was common during the Dust Bowl years in the U.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. 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

2916-537: Was previously thought, most of the Saharan dust that reaches the east coast of the United States originates from a single source—the Bodélé depression. In February 2005 the first field experiment, the Bodélé Dust Experiment or BoDEx 2005, was carried out in the Bodélé Depression. The experiment measured the surface winds and near surface winds, dust concentrations, and the influence of dust on

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