Sahara Desert

The Sahara is a desert, the greatest on earth. This territory became arid already in ancient times. However, there was a period when the Sahara desert was covered with savannas or even forests.

According to some researchers, the climateterritory was more humid in comparison with the present. During the Paleolithic, a man was fishing and hunting, moving away from his home. At that time he was not attached to water sources, like modern oases. However, when the lack of fluid and heat became unbearable for him, he moved to another place. The instruments of labor, which are found on the entire arid territory, attest to human activity.

The modern Sahara desert has an extraordinarydry, especially close to the ground surface, by air. This feature is the result of airflow trade currents. Not the last role belongs to the terrain on which the Sahara desert lies.

It should be noted that there are places on the Earth where absolutelythere is no rain, - a rarity. In some areas of this territory, precipitation does not occur for several years, and sometimes even decades. In this case, the rain does not reach the surface of the soil - because of the high temperature of the soil, the droplets evaporate.

In some areas of the Sahara, downpours can passunexpectedly, causing severe flooding - the territory for several minutes are covered with a water column with human growth. There is an opinion that in this arid region more people died from floods than from drought.

The Sahara Desert, where life is regulatedsun, by right is considered the hottest area on Earth. The high temperature of the soil surface helps to distinguish air masses. In these areas, solar rays are refracted. As a result, mirages arise. On the horizon in the midday heat, an oasis or lake may appear. In fact, they are absent. Visions can occur in air, saturated with dust, before sunrise.

In the afternoon, as you know, it is very hot there. At night, the temperature drops very much, and it becomes quite cold. Temperature fluctuations per day can be up to thirty degrees. However, as practice shows, heat in the desert is tolerated more easily than cold.

Very heavy impact on people havelong sand and dust storms. They are very similar to fires and cover everything around. Storms rush through the plains, knocking rock dust off the destroyed rocks. The strength of the wind can reach, according to the opinion of individual researchers, up to 50 meters per second and more.

After such phenomena, desert air is very electrified. In this case, sparks can be extracted from almost every object.

Hot winds have destructive power. As a rule, they come from the center of the territory and for several hours are able to burn the harvest. Most often such winds begin to blow in the beginning of summer. With the flow of air, not only does the dust move, but small pebbles are also heaped up.

In the Sahara there are also short-term tornadoes. These rotating air streams take the form of pipes. They arise in the daytime due to the heating of the scorched soil. Tornadoes are visible due to the presence of dust in the air currents. However, observations show that such phenomena rarely cause damage. Sometimes they, coming off the surface, continue in the atmosphere.

Animals of the Sahara desert - mostlyrepresentatives of invertebrates. In total there are about four thousand species. In the desert, you can meet and adapted to life in arid areas of mammals - gazelles, antelopes and sometimes predatory foxes. Numerous and reptiles - lizards, lizards, certain types of snakes.

It should be noted the uniqueness of the Sahara. Even in arid places, the integrity of the ecosystem is preserved.

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