Because deserts are so dry, they have very low humidity—the measure of water vapor in the air. At night, the sun no longer heats the desert and the heat from the day doesn't stay trapped. Because of this, some deserts can get cold at night, dropping to below 40F, which is definitely coat weather.
One thing all deserts have in common is that they are arid, or dry. Most experts agree that a desert is an area of land that receives no more than 25 centimeters (10 inches) of precipitation a year. Some deserts are mountainous. Others are dry expanses of rock, sand, or salt flats.
Deserts may seem lifeless, but in fact many species have evolved special ways to survive in the harsh environments. Far from being barren wastelands, deserts are biologically rich habitats with a vast array of animals and plants that have adapted to the harsh conditions there.
The hot desert is a land of extremes: extreme heat and extreme dryness; sudden flash floods and cold nights. Because deserts are such a harsh environment, deserts often have names likes "Death Valley," "the empty quarter," and "the place from where there is no return." Deserts are usually very, very dry.
Deserts are hot primarily because of a lack of water. When the sun shines on the ground, all of the absorbed sunlight goes into raising the ground's temperature. DESERTS ARE COLD AT NIGHT:Because of the lack of water in the ground, and little water vapor in the air, most deserts can get quite cool at night.
The Atacama Desert is commonly known as the driest nonpolar place in the world, especially the surroundings of the abandoned Yungay town (in Antofagasta Region, Chile). Moreover, some weather stations in the Atacama have never received rain.
The Atacama Desert can attribute its astoundingly low precipitation to a combination of several “drying” factors: the subtropical high, a double rain shadow, and the cold ocean current running up the west coast of South America.
The enormous desert spans 11 countries: Algeria, Chad, Egypt, Libya, Mali, Mauritania, Morocco, Niger, Western Sahara, Sudan and Tunisia. The Sahara desert has a variety of land features, but is most famous for the sand dune fields that are often depicted in movies.
Despite harsh conditions, some animals thrive in hot, dry desert climates. These animals include fennec foxes, dung beetles, Bactrian camels, Mexican coyotes, sidewinder snakes and thorny devil lizards.
Hot and dry deserts can be found in North America, Central America, South America, southern Asia, Africa, and Australia. Well-known hot and dry deserts include the Mojave and the Sahara. As the name suggests, these deserts are very hot and very dry. They have two seasons: hot and hotter!
Deserts occur where there is a lack of moisture and thus an abundance of sunlight. With the relative lack in moisture, there is less evaporation. This warming adds to the already warm and dry conditions found at a desert. The sinking air compresses and warms.
1 : arid land with usually sparse vegetation especially : such land having a very warm climate and receiving less than 25 centimeters (10 inches) of sporadic rainfall annually. 2 : an area of water apparently devoid of life. 3 : a desolate or forbidding area lost in a desert of doubt.
Jaisalmer, Hot and DryVery high daytime temperatures, with very little precipitation and a short and mild winter season characterize this climate. Another important characteristic is a high diurnal temperature variation.
Temperate ClimateA continental moderate climate is another sub-type of temperate climates. These regions have hot, rainy summers and cold, dry winters.
Hot deserts are mainly found around the Tropics of Cancer and Capricorn. The hot deserts of the world are located between 15° and 30° north or south of the equator, where the air is subsiding or sinking air (find out why deserts are found along the tropics here).
WEATHER: Weather is not the same in all deserts. The seasons in hot and dry deserts are usually very hot during the summer and warm during the rest of the year. During winter these deserts get little rainfall. Coastal deserts usually have cool winters followed by fairly long, warm summers.
Deserts are formed by weathering processes as large variations in temperature between day and night put strains on the rocks, which consequently break in pieces. Rocks are smoothed down, and the wind sorts sand into uniform deposits. The grains end up as level sheets of sand or are piled high in billowing sand dunes.
New research describes the ancient Trans-Saharan Seaway of Africa that existed 50 to 100 million years ago in the region of the current Sahara Desert. The region now holding the Sahara Desert was once underwater, in striking contrast to the present-day arid environment.
When precession brings Northern Hemisphere summer into alignment with the closest point of Earth's orbit to the Sun, the extra warmth juices the African monsoon and brings water to the desert. So the Green Sahara returns about every 20,000 years, unless other climatic patterns, like large-scale glaciation, intervene.
Only the northernmost and the southernmost fringes of the continent have a Mediterranean climate because they aren't located under the tropics. Because of this geographical situation, Africa is a hot continent as the solar radiation intensity is always high.
Summary: As little as 6,000 years ago, the vast Sahara Desert was covered in grassland that received plenty of rainfall, but shifts in the world's weather patterns abruptly transformed the vegetated region into some of the driest land on Earth.
The answer lies in the climate of the Arctic and northern high latitudes. However, around 5,500 years ago there was a sudden shift in climate in northern Africa leading to rapid acidification of the area. What was once a tropical, wet, and thriving environment suddenly turned into the desolate desert we see today.
The dry subtropical climate of the northern Sahara is caused by stable high-pressure cells centred over the Tropic of Cancer. The annual range of average daily temperatures is about 36 °F (20 °C). Winters are relatively cold in the northern regions and cool in the central Sahara.
What Is Underneath the Sand? Roughly 80% of deserts aren't covered with sand, but rather show the bare earth below—the bedrock and cracking clay of a dried-out ecosystem. Without any soil to cover it, nor vegetation to hold that soil in place, the desert stone is completely uncovered and exposed to the elements.
Deserts are expanding – every year they grow by an area around the size of Ireland. But it's not a natural process; it's manmade. Overgrazing, increasing agriculture, deforestation and a growing use of water are eroding the land. And it is particularly affecting parts of Africa, America or Asia.
