What is Hail? Under what circumstances will there be hail?

Hail, often referred to as hail. Hail is formed in convective clouds, when the water vapor rises with the air flow and cold, it will condense into small water droplets, if the temperature continues to decrease with the increase in height, reaching below zero degrees Celsius, the water droplets will condense into ice particles, in the process of its upward movement, and will adsorb Xiaoice particles or water droplets around it and grow, until its weight can not be carried by the updraft, that is, it will fall, when it falls to a higher temperature zone, its surface will melt into water, and at the same time it will also absorb the surrounding small water droplets, at this time, if it encounters a strong updraft and is lifted again, Its surface condenses into ice, and so on and so on, like a snowball, its volume grows larger and larger, until its weight is greater than the buoyancy of the air, that is, it falls downward, and if it reaches the ground, it is not melted into water and is still a solid ice particle, which is called hail, and if it melts into water, it is the rain we usually see. It is as small as mung beans and soybeans, and as large as chestnuts and eggs.

This is a mathematical conjecture that can be understood by elementary school students, and the whole set of operations has not been separated from addition, subtraction, multiplication and division, but no one has been able to prove it so far. First choose a positive integer, if you choose an odd number, multiply by 3 and add 1, if it is an even number, divide by 2, and you will find that no matter what number you choose, the final result will become 4-2-1.

Hail, also known as hail, is most common in summer or at the turn of spring and summer. The formation process of hail is similar to that of rain. In summer, when a large amount of water vapor rises to a temperature below -20 degrees Celsius, it becomes a Xiaoice droplet, and when the air cannot hold the Xiaoice ball, it falls from the sky.

Hail is hard, spherical, cone-shaped, or irregular solid precipitation. A hail cloud made up of water droplets, ice crystals, and snowflakes is called. Hail, also known as "hail", is commonly known as hail, and in some areas it is called "cold", and it is most common in summer or at the turn of spring and summer.

It is as small as mung beans and soybeans, and as large as chestnuts and eggs.

Hail occurs only in cumulonimbus clouds, where there is a strong flow of air currents. Usually in the direction of the cloud, a very strong updraft flows from the base of the cloud and from the upper part of the cloud. There is also a downdraft flowing in from the middle layer behind the cloud and exiting from the base of the cloud.

Precipitation zones for hail usually appear here. These two organized updrafts and downdrafts are connected to the ambient airflow, so the airflow structure in the general strong hail cloud is more persistent. The updrafts in the clouds are stronger than those of the average thunderstorm cloud, the hail cloud is transported by the strong updraft to carry sufficient water vapor, and the hail particles are supported to stay in the cloud, causing it to grow to a considerable size before landing.

Xiaoice hail grows in convective clouds by several times when the hail embryo collides with supercooled water droplets, and descends to the ground when the updraft in the cloud cannot support it. Large hail is produced in thunderstorm clouds with a strong updraft and abundant liquid water.

Rain and snow fall from the clouds, and so does hail. However, hail clouds are a very well-developed cumulonimbus cloud, and only particularly vigorously developed cumulonimbus clouds are likely to hail. Hail disaster is a kind of violent meteorological disaster caused by strong convective weather system, although its scope is small, the time is relatively short, but it is fierce and intense, and often accompanied by gusting winds, heavy precipitation, sharp cooling and other paroxysmal disastrous weather processes.

The range of each hail is very small, generally a few meters to several kilometers in width and 20 to 30 kilometers in length. Hail, on the other hand, usually in the mid-latitude continental regions, where there are usually more mountainous areas than plains, and more inland than coastal areas, often occurs.

On June 2, 1989, the Dezhou area of Shandong Province was hit by hailstorms, and the wind reached more than 8 levels, the smallest hail was like red dates, and the largest was like eggs. As a result, 10,000 hectares of wheat, cotton, melons and vegetables were affected, more than 7,000 trees were fell, and more than 5,000 livestock and poultry were killed, and the economic loss amounted to more than 200 million yuan.

On July 9, 1990, the city of Sanmenxia in Henan Province was hit by hailstorms, with winds reaching a maximum of 10, affecting 21 townships in 4 counties in Sanmenxia City. The hail lasted for 1 hour, and the largest hailstone weighed kilograms. The province was affected by 10,000 hectares of crops, more than 6,000 houses were damaged, more than 700 people were killed, more than 70 trees were broken, more than 3,400 high and low voltage communication poles were damaged, and 300,000 meters of lines were damaged.

Violent hailstorms have destroyed crops, damaged houses, injured people and killed livestock.

Extra-large hailstones can be even larger than grapefruits, so the larger the hail, the more destructive it is. Hail can also destroy large areas of farmland and trees, destroy buildings and vehicles, etc., threatening the safety of people and animals, and is a serious natural disaster with great lethality.

When the surface water is exposed to the sun and vaporized, and then rises into the air, a lot of water vapor comes together and condenses into clouds, at this time the relative humidity is 100%, and when it encounters cold air, it liquefies, and the dust in the air is used as condensation nuclei to form raindrops (tropical rain) or ice crystals (mid-latitude rain), which are getting bigger and bigger.

When the temperature drops to a certain level, the air is oversaturated, so it rains, if it encounters cold air and there is no condensation nucleus, the water vapor condenses into ice or snow, which is snow, and if the temperature drops sharply, it will form a large ice mass, that is, hail.

It is related to the weather system, and it is also greatly affected by the topography and landform. China has a vast territory, complex topography, and great differences in landforms, and China has the largest plateau in the world, which makes the atmospheric circulation complicated. Therefore, the hail weather in China has a large impact and a wide range of hail disasters.

According to the comparative analysis of the spatial pattern of hail disasters in China, the following four aspects are understood.

1. Hailstorms have a wide range of impacts. Although hail disaster is a small-scale disaster event, there are hail disasters in most parts of China, and almost all provinces have more or less records of hail disasters, and the number of affected counties is close to half of the number of counties in the country, which fully shows that the distribution of hail disasters is quite extensive.

2. The distribution of hail disasters is highly discrete. Most of the hail falls in individual counties and districts.

3. The distribution of hail disasters is obvious. Hail disasters mostly occur in certain specific areas, especially in the piedmont areas and agricultural areas east of the Qinghai-Tibet Plateau, which are closely related to the conditions for the formation of hail disasters.

4. The overall distribution pattern of hail disasters in China is more in the central and eastern parts and less in the west, and the spatial distribution presents a pattern of one region, two belts and seven centers.

One of the areas refers to the area north of the Yangtze River, south of the Yanshan Mountains, and east of the Qinghai-Tibet Plateau, which is a hailstorm-prone area in China.

The seven centers refer to several hailstorm-prone centers scattered in the two hail belts: the Northeast High Value Area, the North China High Value Area, the Hubei Henan High Value Area, the Nanling High Value Area, the East Sichuan, Western Hunan, Ganqing East High Value Area, and Kashgar Aksu High Value Area.

Hail, also known as "hail", is commonly known as hail, and in some areas it is called "cold", and it is most common in summer or at the turn of spring and summer. It is as small as mung beans and soybeans, and as large as chestnuts and eggs.

The formation of hail requires the following conditions.

There must be a rather cautious layer of instability in the atmosphere.

Curomulus clouds must develop to a height that can freeze individual large water droplets (generally thought to be temperatures up to -12 -16).

There should be strong wind shear.

The vertical thickness of the cloud cannot be less than 6 8 km.

Cumulonimbus clouds contain abundant water. Generally 3 8 g m3 with a cumulative band of liquid supercooled water above the maximum rising velocity.

There should be an oblique, strong and uneven updraft in the cloud, generally more than 10 laughing cracks for more than 20 m seconds.

<>1. Hail (hail) is also called "hail", commonly known as hail, "pretending to be a trembling book", and some areas are called "cold" (such as Xuzhou, Gansu and other places), which is a weather phenomenon, and is most common at the turn of summer or spring and summer. It is as small as mung beans and soybeans, and as large as chestnuts and eggs.

2. When the surface water is exposed to the sun and vaporized, and then rises into the air, a lot of water vapor is together, condensed into clouds, at this time the relative humidity is 100%, when it encounters cold air, it is liquefied, and the dust in the air is condensed to form raindrops (tropical rain) or ice crystals (mid-latitude rain), which is getting bigger and bigger, when the temperature drops to a certain extent, the water vapor of the air is supersaturated, so it rains, if it encounters cold air and there is no condensation nucleus, the water vapor will condense into ice or snow, which is snow, If the temperature of the hall drops sharply, large ice masses, known as hailstones, will form.

3. All parts of China are affected by different degrees of hailstorms every year. Especially in the mountainous and hilly areas in the north, the eastern part of the Qinghai-Tibet Plateau, and the Yunnan-Guizhou area, the terrain is complex, the weather is changeable, the hail is many, and the damage is very serious, which is very harmful to agriculture. Violent hailstorms often destroy crops, damage houses, and smash people and livestock. Huge hailstorms, even larger than grapefruits, can kill people, destroy vast tracts of farmland and trees, destroy buildings and vehicles, and more.

It has great lethality. Hailstorm is one of the most serious natural disasters in China.