What strange phenomena are there in the desert?

There is a kind of "gravel circle" in the desert, which is wonderful. After hundreds of years of thermal expansion and cold contraction, a big stone has been broken again and again, forming a round gravel circle on the ground, which is like a man-made arrangement. In fact, it is the natural bending deformation of objects.

Fried eggs can be found on the sand.

1) Less precipitation and large variability: Aswin in the Sahara Desert of North Africa has a record of no rain for many years; In Allica, a desert in northern Chile, South America, there have been only three showers that can measure rainfall in a row 17 years, and the total amount of the three showers is only 0.5 1 mm, with very little precipitation. Iquiji, also located in the desert of northern Chile, had no rain for four consecutive years, but in the fifth year, a shower dropped by 65,438+05 mm, and in the second year, a shower record reached 63.5 mm, showing great variability. Rainfall in tropical deserts is mostly explosive showers, which often cause serious soil erosion.

(2) High temperature and large temperature difference: Due to less clouds, strong sunshine, insufficient vegetation coverage and low air humidity, the temperature rises extremely rapidly during the day. It is recorded that the temperature in North Africa is as high as 58℃. Generally, the average monthly temperature in summer is between 30℃ and 35℃, and the high temperature lasts for a long time. For example, in Aden, Arabian Peninsula, the monthly average temperature is above 30℃ for five months in a year. The desert is cooler at night, because there is no cloud all night, and the ground radiation is strong and the heat dissipation is fast. The lowest temperature at night is usually between 7℃ and 12℃, and there are also days of thin frost. The annual temperature difference is generally around 10℃~20℃, and the daily temperature difference is even larger, between 15℃~30℃. At a weather station south of Tripoli in North Africa, 1978,1February 25th, 978, it was recorded that the highest temperature in Jedaias during the day was 37.2℃, but at night, the lowest temperature dropped to -0.6℃, and the daily temperature difference reached 37.8℃, which was really "wearing a fur coat in the morning and wearing yarn in the afternoon".

(3) Strong evaporation and low relative humidity: Tropical desert climate is often cloudless, windy, sunny, high temperature and low relative humidity in Wan Li, so it has strong evaporation. The possible evapotranspiration is 20 times or even about 100 times of precipitation. The relative humidity in the air is very small, and it often appears at about 2% in the Sahara desert of Egypt.

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