Are hailstones crystals?

What is the standard for hail?

I think hail, ice crystals and snowflakes are all crystallized natural phenomena of precipitation. There is no essential difference. The only difference is that ice crystals and snowflakes are not lethal when they fall. Hail is different and very painful

How is hail formed?

First, the water on the ground vaporizes (that is, turns into water vapor) and rises. When it reaches high altitude, it is no longer the same as the earth's air pressure. As it rises, it gathers together and becomes clouds. As more water accumulates, the vaporized water falls down as liquid water and becomes rain. This phenomenon has an additional link in winter. When the altitude is too cold, it condenses into crystals. Generally speaking, please click What falls should be snow, and the temperature at which hail forms is lower than the temperature at which snow forms. When the temperature reaches the temperature that can form hail, the falling snowflakes combine with each other in the air and become larger and larger to become hail_______. Share it with me. I have to reward you for typing for so long, right? Thank you in advance______

Why does hail always appear in summer?

How can hail disaster occur in summer?

First, let us look at why it rains in the sky. In meteorology, precipitation refers to the natural phenomenon of water falling from the atmosphere to the ground, including rain, snow, hail, etc.

As we all know, clouds are formed from water vapor. Due to the low temperature in the high altitude, the suspended particles in the air absorb the water in the clouds and form very small water droplets or ice crystals. They continue to absorb the water in the clouds and gradually form larger water droplets (small ice crystals can also absorb a large amount of water). into larger water droplets). As the water droplets continue to absorb moisture from the clouds, the water droplets continue to grow until their weight exceeds the levitation force provided by the air. These water droplets fall to the earth to form rain. If the temperature is very low, the water precipitated in the clouds is frozen into small ice crystals (tiny water droplets that have formed in the clouds can also be frozen into small ice crystals). The small ice crystals absorb water and continue to expand, forming larger hexagonal ice crystals. When the hexagonal crystals are so large that they exceed the buoyancy of the air, they fall into snow.

Hail is ice particles and ice cubes falling from the sky. Its particle size is generally 5-10 mm. According to literature, the largest particle size can reach more than 300 mm. Hail falling from the sky can cause great damage to houses, people, livestock, crops, etc., causing disasters. Hail is a product of convective weather, formed in thick and powerful cumulonimbus clouds, which are meteorologically called deep and unstable stratification.

In strong convective weather, the small water droplets in cumulonimbus clouds gradually increase their weight, and when they exceed the suspension capacity of the air, they begin to fall. However, these small raindrops that should have fallen to the earth encounter updrafts during the landing process, causing the small raindrops to rise back to the upper part of the clouds, and often rise and fall repeatedly. In this process, the raindrops continue to absorb the moisture in the clouds, becoming more and more deformed. Finally, the updraft can no longer support it, so it falls to the ground and forms extremely heavy raindrops, which becomes a heavy rain.

The temperature at high altitude is very low. If it is below 0℃, small water droplets will form small ice crystals. The ice crystals will continue to absorb water, gradually increase in volume and fall. When encountering an updraft during the landing, the small ice crystals are sent up to the high-altitude clouds below 0°C, where they continue to absorb water and grow until they fall again when the updraft cannot support them, and then rise with the updraft... After many repetitions, the ice crystals turned into larger ice cubes.

Generally, relatively large ice particles may be produced in developing thick cumulonimbus clouds. But it may not necessarily fall to the ground and become hail. Only when the ice particles repeatedly rise and fall with the airflow in the high-altitude clouds and continue to grow to large enough particles, will they fall from the sky into hail.

The above-mentioned strong convective weather usually occurs in summer. In thick and strong cumulonimbus clouds in summer, this meteorological condition may produce both hail and thunderstorms. However, in most cases, only thunderstorms are produced because the requirements for producing hail are more stringent. Meteorologists tell us that whether hail occurs is related to the thickness of cumulonimbus clouds, the height and temperature of the atmosphere at the top of the clouds, the speed of the updraft, etc.

If the cumulonimbus clouds are particularly thick and the upper part of the cloud layer is in a very high atmospheric space, the temperature there will be very low. The small water droplets will be sent to the low temperature area of ??the upper part of the cloud layer by the updraft and will be blown away. Freezes into tiny ice particles. Even if it is melted by the high summer temperature at low altitude during the descent, it will refreeze when it is carried to high altitude again by the air flow. In this way, it goes up and down repeatedly with the airflow. As long as the high-altitude low-temperature clouds below 0°C have enough thickness, the ice particles will be slightly melted and then frozen again. Because it melts slowly and freezes quickly, the ice particles continue to absorb moisture from the clouds as they rise and fall repeatedly. As a result, the ice particles become larger and larger as they freeze. When the updraft can no longer support them, they fall to the ground and form hailstones.

According to the calculations of meteorologists, the speed of updrafts at about 10 meters/second can produce thunderstorms; but only when the speed of updrafts reaches more than 20 meters/second can hail be produced. Moreover, the high-altitude part of the cumulonimbus cloud layer below 0°C must also have a large thickness to ensure that small water droplets or small ice particles rise with the airflow and stay in the low-temperature area for enough time to be frozen into ice, and to ensure that they can be frozen repeatedly. The rate of melting during lifting is slower than the rate of freezing. Only in this way can the small ice particles freeze larger and larger as they move up and down with the airflow, and finally become so large that the airflow cannot support them and fall to the ground into hailstones.

This kind of special meteorological condition is quite rare. Even in summer, there are not many opportunities to occur, and it is even less likely to occur in other seasons. Therefore, the chance of hail falling is very small, and it is mainly in summer.

Most hail disasters in my country occur from April to July, usually from the afternoon to the evening. Because of the frequent heating and cooling activities during this period, it is relatively easy to form special meteorological conditions for hail to fall. From the land where hail falls in our country...>>

What is the difference between graupel and hail? Are they two names for the same substance?

Graupel

White opaque conical or spherical solid precipitation particles, which often appear to fall in sudden bursts, often rebound on hard ground, and are brittle and fragile when encountering water vapor in high altitudes. Small ice particles condensed from cold air often appear before or during snowfall. In summer, in high mountain areas, there are often many supercooled water droplets in the sky that freeze around the crystallization core, forming a kind of white matte round particles. In meteorology, this kind of thing is called graupel. In different areas, there are meters. Snow, snow graupel, snow seeds, snow grits, snow beans and other names. The diameter of graupel is generally between 0.3 and 2.5 mm. It is brittle and easily crushed. Graupel does not belong to the category of snow, but it is also a type of atmospheric solid precipitation. It often occurs at 0 degrees Celsius, and may also exist at temperatures around -40 degrees Celsius, and is in an unfrozen state. Graupel usually appears before or during snowfall. The code name in routine aviation weather reports is GS.

Hail

Also called "hail", commonly known as hailstones, or "lengzi" in some areas, it is most common in summer or at the turn of spring and summer. They are ice particles as small as mung beans and soybeans and as large as chestnuts and eggs. Except for Guangdong, Hunan, Hubei, Fujian, Jiangxi and other provinces where hail is relatively rare, all regions in my country are subject to varying degrees of hail disasters every year. Especially in the mountainous and hilly areas in the north, the terrain is complex, the weather is changeable, hail is abundant, and the damage is severe, which is very harmful to agriculture. Violent hail destroys crops, damages houses, and often injures people and kills livestock; extremely large hail can even be larger than a grapefruit, killing people, destroying large areas of farmland and trees, destroying buildings and Vehicles etc. Has powerful lethality.

Around 8 o'clock yesterday, people who went to work found white objects falling from the sky, which were very similar to "hail". In suburban orchards, there was even a thick layer of "hail" left on the ground. . At the same time, many citizens heard faint thunder in the sky. Monitoring by the meteorological department showed that thunder was observed at three meteorological stations in Shunyi, Changping and Xizhaitang. Zhang Mingying explained that the white crystals that are very similar to "hail" are not hail, but a type of ice particles called graupel. From the appearance, hail is translucent, while graupel is an opaque crystal. Graupel rarely appears, but it is also A normal weather phenomenon. Thunder and graupel are both uninvited guests in rainy and snowy days. Experts believe that this is related to the different ways of impact of cold air. If the cold air affects the low-level air, strong winds and cooling will occur. Early yesterday morning, when a cold air front affected Beijing, it rapidly cooled the altitude of 1,500 meters. Water vapor crystallized at an altitude of 1,200 meters, but had no time to melt during the descent, thus forming graupel. At the same time, there was an imbalance in the sky over Beijing, with the top becoming colder and the bottom still being warm. The atmosphere was unstable and the upper air temperature was very low, forming special strong atmospheric convection, resulting in thunder.

What are the names of the physical changes of ice, snow, hail, dew, fog, frost, rain and clouds?

① Cloud: The water vapor in the air liquefies into small water droplets when it is cooled, and the small ice crystals that condense are mixed together to form clouds; ② Rain: The small water droplets and small ice crystals in the cloud gather It will fall to a certain extent. During the descent, the ice crystals melt into water droplets and form rainfall; ③ Dew: The water vapor formed in the air will liquefy into small water droplets on the cold ground, flowers, plants, and stones at night. This is dew. ; ④ Fog: If there is a lot of floating dust in the air, when the temperature drops, the water vapor will liquefy into small water droplets and adhere to the floating dust, which is fog; ⑤ Hail: In summer, the rising airflow is very strong and very unstable. , small water droplets are cooled and solidified into small hailstones in the air convection. The small hailstones merge with small ice crystals and small water droplets during the flow process, forming large ice cubes with alternating layers of transparent and opaque layers. When it increases to a certain extent, the airflow cannot support it and falls to the ground. This is hail. ⑥Frost: On nights in late autumn or winter, when the ground temperature drops rapidly below 0°C, the water vapor in the air will release a large amount of heat and quickly condense directly on the ground, flowers, grass, and stones to form small solid crystals. , this is frost; ⑦ Snow: Water vapor in the air condenses into small ice crystals. When the small ice crystals fall from high altitude, they rub with the air and form snowflakes. So the answer is: dew - liquefaction; fog - liquefaction; frost - condensation.