Why are mirrages caused in the desert?
112605
A mirage is a naturally occurring optical phenomenon. The kind most commonly seen (inferior mirage - where the inverted image lies below the upright one) is produced by the refraction of light when it passes into a layer of warm air lying close to a heated ground surface. In deserts, mirages may give the appearance of a lake or other large body of water in the distance; as the previous writer stated, this is actually an image of the sky being refracted back up from the warm air lying over the sand.
332776
Dust devils are smaller and weaker than tornadoes, and arise from significantly different atmospheric conditions. They are caused by convection on hot, calm summer days. Air near the surface (ground) becomes much warmer than the air above, creating an updraft. Dust devils may rotate clockwise or counterclockwise, and their movement is slow and sporadic as they travel from one patch of warm air to another.
711776
it happens from a change of weather, it can happen if u dont take good care of yourself take your vitamins or wear socks all the time it happens.
243033
This sounds like a condition that would occur over very hot, dry deserts, or other areas that are more temporarily hot and dry.
28075
A dust storm (or sandstorm in some contexts) is a meteorological phenomenon common on the Great Plains of North America, in Arabia, the Gobi Desert of Mongolia, the Taklamakan Desert of northwest China, the Sahara Desert of northern Africa,Thar Desert of India and other arid and semi-arid regions. Such a storm is usually the result of convection currents created by intense heating of the ground. The air over the sand becomes hot, and rises. This creates differences in air pressure and temperature, and the cooler winds begin to rush in. The wind is strong enough to move dunes, and it often interferes with travel, sometimes obliterating roads in flat dry regions such as those of the western United States. The simoom or simoon (sîmūm, sîmūn) is the dust- and sand-laden desert wind of N Africa and Arabia that contributes largely to the atmospheric dust over Europe; evidence of the dust from simoon winds has also been found on the seafloor at considerable distances from shore. The haboob (həbūb) is a sandstorm prevalent in the region of Sudan around Khartoum. Sandstorms, the leading edges of which often appear as solid walls of dust as much as 5,000 ft (1,525 m) high, also occur, although less frequently, in the SW United States. One that occurred near Tucson, Arizona, on July 16 1971, was extensively documented by meteorologists. Similar duststorms from windborne particles are evident on the planet Mars and are thought to be seasonal. Severe dust storms can reduce visibility to zero, making travel impossible, and can blow away valuable topsoil, while depositing soil in places where it may not be wanted. Drought and wind contribute to the emergence of dust storms, as do poor farming and grazing practices. The dust picked up in such a storm can be carried thousands of kilometers: Sahara dust storms influence plankton growth in the western Atlantic Ocean and, according to some scientists, are an important source of scarce minerals for the plants of the Amazon rainforest. Dust storms can often be observed from satellite photos.
1089980
Water\n\nSplash erosion is the detachment and airborne movement of small soil particles caused by the impact of raindrops on soil. Sheet erosion is the result of heavy rain on bare soil where water flows as a sheet down any gradient, carrying soil particles. Where precipitation rates exceed soil infiltration rates, runoff occurs. Surface runoff turbulence can often cause more erosion than the initial raindrop impact. Gully erosion results where water flows along a linear depression eroding a trench or gully.\n\nValley or stream erosion occurs with continued water flow along a linear feature. The erosion is both downward, deepening the valley, and headward, extending the valley into the hillside. In the earliest stage of stream erosion, the erosive activity is dominantly vertical, the valleys have a typical V cross-section and the stream gradient is relatively steep. When some base level is reached the erosive activity switches to lateral erosion which widens the valley floor and creates a narrow floodplain. The stream gradient becomes nearly flat and lateral deposition of sediments becomes important as the stream meanders across the valley floor. In all stages of stream erosion by far the most erosion occurs during times of flood, when more and faster-moving water is available to carry a larger sediment load. In such processes, it is not the water alone that erodes, suspended abrasive particles, pebbles and boulders can also act erosively, as they traverse a surface.\n\nWind\n\nWind erosion, also known as eolian erosion is the movement of rock and/or sediment by the wind. Windbreaks are often planted by farmers to reduce wind erosion. This includes the planting of trees, shrubs, or other vegetation, usually perpendicular or nearly so to the principal wind direction. The wind causes dust particles to be lifted and therefore moved to another region. Wind erosion generally occurs in areas with little or no vegetation, often in areas where there is insufficient rainfall to support vegetation. An example is the formation of sand dunes, on a beach or in a desert.\n\nGlacial\n\nIce erosion is caused by movement of ice, typically as glaciers. Glaciers can scrape down a slope and break up rock and then transport it, leaving moraines, drumlins and glacial erratics in their wake, typically at the terminus or during glacier retreat. Ice wedging is the weathering process in which water trapped in tiny rock cracks freezes and expands, breaking the rock. This can lead to gravity erosion on steep slopes. The scree which forms at the bottom of a steep mountainside is mostly formed from pieces of rock broken away by this means. It is a common engineering problem, wherever rock cliffs are alongside roads, because morning thaws can drop hazardous rock pieces onto the road.
629574
deserts exists in almost all types of altitudes. it is caused due to lack of water and abudance of sand. so i would say the average would be the mid point between below sea level and mountanous level(5000 mts)...that would be about 2500 or less mts
480792
Deserts can form in several ways that I know of...\n\nRainshadow effect on the leeward side of a mountain range. Most of the water is wrenched out of the air masses before they reach the other side of the range. This is due to the lifting of the air. It is forced to rise, condenses due to adiabatic cooling, & precipitates.\n\nThe most influential cause would be high pressure belts located around the world. These places are roughly located around the tropics of cancer & capricorn. In these areas, the high pressure is pushing down air. When there is a continuous belt of high pressure, air doesn't rise. If air doesn't rise then clouds can't form & rain won't happen. The Sahara & the Kalahari in Africa are examples.\n\nAnother would be inland deserts. They are so far removed from sources of moisture that they simply never get any. If I am not mistaken, the Gobi Desert is one.
620422
There's lots of stuff blowing up from lots of places.  Dust storms in the Sahara desert blow tons into the Atlantic ocean.  Volcanos in the southwestern Pacific will color the North American skies.  The atmosphere has a lot of currents.  The jet stream is one, prevailing winds are another.\n\nThe earth has bands of atmospheric rotation.  I live in a zone called the prevailing westerlies.  Most of the winds tend to flow in a west to east direction.  If you are in North America, that Scandinavian pollen will have traveled the width of Asia, at its widest, raining down all along the way.  This shows the global nature of this zone of air flow.\n\nSomethings are simply too big for those zones to contain, in 1883 when Indonesian volcano Krakatoa exploded, its ash was seen in England.  May I suggest an article by Timothy Miner in the May 1, 2003 issue of Flying Safety.  Not all pollen, dust, pollutants travel that far.  Some are not as aerodynamic as others, and sometimes winds are not as strong when the pollination is taking place.  Still, there are times when smoke, ash, pollen, and other things can travel long, long distances when they are usually confined to very short areas.\n\nIf you have ever seen photos of great dust storms, consider that we call them sand storms, but the sand is only blowing up a very few feet from the ground.  Those enormous clouds of dirt are the dust the wind carries high into the air, taking them miles and miles away from their source, while the original sand the dust was shaken out of has fallen but a few fee from its original disturbance.  Pollen works that way too.
722861
The middle east is mostly arid. The other three have widely contrasting terrains.
138955
I'm not familiar with this desert, but since all deserts are dry, and a most are hot, you can probably assume that the desert will be hot and dry.
92526
Adaptation, which means that they develop special roots and leaves that make them more prone to survive. Such as some plants have waxy leaves in order to withstand high temepratures and various other conditions. In deserts, some plants have very long roots, which affects if there population is random or very populated.
970654
The formation of deserts has a lot to do with lattitude.  Most deserts are located in sub-tropical areas where high pressure is created by the circulation of air after it is heated in the tropics.  These areas have an almost perminent supply of a high pressure system that prevents a lot of precipitation and allows for extremely high temperatures.
557119
Sand in the ocean deals with water. Sand in the desert would be dealing with wind and heat. Ocean water also contains minerals/salts which may be adhering or tearing away at the sand. The only water desert sand may ever encounter is more than likely the rare rainfall- freshwater, which if anything would help "wash" away any minerals bonding to it. Wet vs. Dry- either way sand gets in places you don't want it... So just keep away from it unless you're gonna superheat the stuff and make glass.. heheh.
747499
What causes erosion to be severe in some areas and minor elsewhere is a combination of many factors, including the amount and intensity of precipitation, the texture of the soil, the gradient of the slope, ground cover (from vegetation, rocks, etc.) and land use. The first factor, rain, is the agent for erosion, but the degree of erosion is governed by other factors.\n\nThe first three factors can remain fairly constant over time. In general, given the same kind of vegetative cover, you expect areas with high-intensity precipitation, sandy or silty soils and steep slopes to be the most erosive. Soils with a greater proportion of clay that receive less intense precipitation and are on gentle slopes tend to erode less. But here, the impact of atmospheric sodium on erodibility of clay should be considered.\n\nThe factor that is most subject to change is the amount and type of ground cover. When fires burn an area or when vegetation is removed as part of timber operations or building a house or a road, the susceptibility of the soil to erosion is greatly increased.\n\nRoads are especially likely to cause increased rates of erosion because, in addition to removing ground cover, they can significantly change drainage patterns. A road that has a lot of rock and one that is "hydrologically invisible" (that gets the water off the road as quickly as possible, mimicking natural drainage patterns) has the best chance of not causing increased erosion.\n\nUnderstandably, many human activities remove vegetation from an area, making the soil easily eroded. Logging and heavy grazing can reduce vegetation enough to increase erosion. Changes in the kind of vegetation in an area can also effect erosion rates. Different kinds of vegetation effect infiltration rates of rain into the soil. Forested areas have higher infiltration rates, so precipitation will result in less surface runoff, which erodes. Instead much of the water will go in subsurface flows, which are generally less erosive. Leaf litter and low shrubs are an important part of the high infiltration rates of forested systems, the removal of which can increase erosion rates. Leaf litter also shelters the soil from the impact of falling raindrops, which is a significant agent of erosion. Vegetation can also change the speed of surface runoff flows, so grasses and shrubs can also be instrumental in this aspect.\n\nOne of the main causes of erosive soil loss in the year 2006 is the result of slash and burn treatment of tropical forests. When the total ground surface is stripped of vegetation and then seared of all living organisms, the upper soils are vulnerable to both wind and water erosion. In a number of regions of the earth, entire sectors of a country have been rendered unproductive. For example, on the Madagascar high central plateau, comprising approximately ten percent of that country's land area, virtually the entire landscape is sterile of vegetation, with gully erosive furrows typically in excess of 50 meters deep and one kilometer wide. Shifting cultivation is a farming system which sometimes incorporates the slash and burn method in some regions of the world.\n\nWhen land is overused by animal activities (including humans), there can be mechanical erosion and also removal of vegetation leading to erosion. In the case of the animal kingdom, this effect would become material primarily with very large animal herds stampeding such as the Blue Wildebeest on the Serengeti plain. Even in this case there are broader material benefits to the ecosystem, such as continuing the survival of grasslands, that are indigenous to this region. This effect may be viewed as anomalous or a problem only when there is a significant imbalance or overpopulation of one species.\n\n Bank erosion started by four wheeler all-terrain vehicles, Yauhanna, South CarolinaIn the case of human use, the effects are also generally linked to overpopulation. For when large numbers of hikers use trails or
281628
Beautiful landscape, dry desert climate, mixed in with thunderstorms, year-round...cold nights, almost unbearably hot days in the summer!
23018
A rain shadow forms on the side of a mountain that doesn't receive much rain. The reason for this is that clouds tend to form over an ocean, where there is a lot of moisture, and then move inland. The heating and cooling patterns where land meets ocean cause moisture laden clouds to move inland. When cloids encounter a mountain range, air flow is pushed upward, the air becomes colder and can't hold as much moisture, and it rains. This is called the orographic effect.\n\nOn the other side of the mountain, clouds have been emptied of most of their moisture, and a "rain shadow" is created, which is an area that receives little rain. This is why deserts form on the leeward side of mountains, meaning the downwind side of the mountain.\n\nIf you look at a map of Southern California, the Mohave Desert is in a rain shadow.