Why does it snow?

Question 1: Why does it snow in winter? The temperature in winter is quite low, and the temperature on the ground is also below zero, so the temperature of the high-altitude clouds is even lower. The water vapor in the clouds can directly condense into small ice crystals and small snowflakes. When these snowflakes grow to a considerable extent, the airflow cannot support them, and they will fall from the clouds to the ground. This is snow.

Because there is a very strong updraft, the temperature of the air is very high, and the snowflakes take a long time to grow in the clouds, so the snowflakes that fall are very large. At the same time, due to the large area of ??snowflakes, the resistance they receive is also large. They float in the air and will not fall to the ground quickly. Therefore, they collide with other snowflakes in the air, stick to each other, and become larger and larger. When they are close to the ground, they start to fly. It’s snowing

Question 2: Why does it snow in winter? Water is the foundation for the existence of all living things on the earth. The changes and movements of water have created our world today. On the earth, water is constantly circulating. Water in the ocean and on the ground is heated and evaporates into the sky. This water vapor moves to other places with the wind. When it encounters cold air, it forms precipitation and returns to the earth's surface. . There are two types of precipitation: one is liquid precipitation, which is rain; the other is solid precipitation, which is snow or hail.

Precipitation in the atmosphere that falls on the earth's surface in a solid form is called atmospheric solid precipitation. Snow is the most widespread, common and dominant form of solid precipitation in the atmosphere. Atmospheric solid precipitation is diverse. In addition to beautiful snowflakes, it also includes hail that can cause great damage, as well as snow graupel and ice particles that we do not often see.

Due to differences in meteorological conditions and growing environments in the sky, various atmospheric solid precipitations are caused. The names of these atmospheric solid precipitations vary from place to place and from person to person. They have many names and are extremely inconsistent. For the sake of convenience, the International Snow and Ice Committee of the International Hydrological Association convened a specialized international conference in 1949 on the basis of soliciting opinions from experts from various countries. At the meeting, a proposal for a concise classification of atmospheric solid precipitation was adopted. This concise classification divides atmospheric solid precipitation into ten types: snow flakes, star-shaped snowflakes, columnar snow crystals, needle-shaped snow crystals, dendritic snow crystals, axis-shaped snow crystals, irregular snow crystals, graupel, ice particles and hail . The first seven are collectively called snow.

Why can’t the latter three be called snow? It turns out that there are two processes for turning gaseous water vapor into solid water. One is that the water vapor first turns into water, and then the water condenses into ice crystals; the other is that the water vapor directly turns into ice crystals without passing through water. This process is called water vapor. Sublime. Therefore, snow is solid precipitation that comes from the water vapor in the sky. (Ten atmospheric solid precipitation forms: snow flakes, star-shaped snowflakes, columnar snow crystals, needle-shaped snow crystals, dendritic snow crystals, axis-shaped snow crystals, irregular snow crystals, graupel, ice particles, and hail).

Question 3: Why is it snowing in the house? Check the Internet to find out the reasons for snowing.

Question 4: Why is it snowing? The snowflakes we see falling from the sky generally come from nimbostratus and altostratus clouds. Water vapor in clouds forms cloud droplets under the action of condensation nuclei. When the temperature in the cloud drops below zero degrees Celsius, the cloud droplets form ice and snow crystals. On the one hand, these ice crystals fall as the sublimation increases and their weight increases. On the other hand, they follow the horizontal airflow, updraft airflow and turbulent movement in the clouds. In this way, water vapor continues to condense on the surface of the ice crystals, and the ice crystals continue to grow and expand. Finally, Snowflakes are formed. When the updraft is not strong enough to bear its weight, the snowflakes will fall all the way down. When the temperature in winter remains below zero degrees Celsius, the snowflakes will fall from the air to the ground.

Question 5: Why does the weather get colder and snowier? The cold wave came early this year. The cold air brought by the Asian high pressure meets the warm air, causing cooling. Snowfall occurs when cold air meets warm and humid airflow and the temperature drops below 0 degrees Celsius, so precipitation appears in the form of snow. . Influenza is prone to outbreaks in winter, so please pay attention to this weather. Thanks for adopting.

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Question 6: What conditions are required for snow to fall? How can water vapor moving in the sky form snow? Is it ok if the temperature is below zero? No, for water vapor to crystallize and form snow, two conditions must be met:

One condition is saturation of water vapor. The maximum amount of water vapor that air can contain at a certain temperature is called the saturated water vapor amount. The temperature at which air reaches saturation is called the dew point. When saturated air cools to a temperature below the dew point, excess water vapor in the air turns into water droplets or ice crystals. Because the saturated water vapor content of the ice surface is lower than that of the water surface, the water vapor saturation required for the growth of ice crystals is lower than that of water droplets. In other words, water droplets must grow when the relative humidity (relative humidity refers to the ratio of the actual water vapor pressure in the air to the saturated water vapor pressure of the air at the same temperature) is not less than 100%; as for ice crystals, the relative humidity is often less than 100% It can also grow over time. For example, when the air temperature is -20°C and the relative humidity is only 80%, ice crystals can grow. The colder the temperature, the less humidity required for ice crystals to grow. Therefore, in high-altitude and low-temperature environments, ice crystals are easier to produce than water droplets.

Another condition is that there must be condensation nuclei in the air.

Someone has done experiments and found that if there are no condensation nuclei, the water vapor in the air can condense into water droplets only when it is supersaturated to a relative humidity of more than 500%. But such a large supersaturation phenomenon does not exist in the natural atmosphere. Therefore, without condensation nuclei, it would be difficult to see rain and snow on our earth. Condensation nuclei are tiny solid particles suspended in the air. The most ideal condensation nuclei are those material particles that absorb water the most. For example, particles of sea salt, sulfuric acid, nitrogen and other chemicals. That’s why we sometimes see clouds in the sky but no snowfall. In this case, people often use artificial snowfall.

Question 7: Why does it snow in spring? Snowing has nothing to do with the season. It mainly depends on the convection and intersection of cold air and warm and humid air. It’s just that the snow pair occurs in winter, and the temperature does not rise significantly in early spring. , it will still snow when encountering cold air! Because the temperature is high in summer, when the snow falls close to the ground, it is mostly ice crystals or rain!

Question 8: Why does it snow in winter? The temperature in winter is quite low, and the temperature on the ground is also below zero, so the temperature of the high-altitude clouds is even lower. The water vapor in the clouds can directly condense into small ice crystals and small snowflakes. When these snowflakes grow to a considerable extent, the airflow cannot support them, and they will fall from the clouds to the ground. This is snow.

Because there is a very strong updraft, the temperature of the air is very high, and the snowflakes take a long time to grow in the clouds, so the snowflakes that fall are very large. At the same time, due to the large area of ??snowflakes, the resistance they receive is also large. They float in the air and will not fall to the ground quickly. Therefore, they collide with other snowflakes in the air, stick to each other, and become larger and larger. When they are close to the ground, they start to fly. It’s snowing

Question 9: Why is it snowing? Ice is formed by the solidification of water, and snow is formed by the condensation of water. The formation and types of snow We all know that clouds are composed of many small water droplets and small ice crystals, and raindrops and snowflakes are formed by the growth and enlargement of these small water droplets and small ice crystals. So, how is snow formed? In water clouds, cloud droplets are all small water droplets. They mainly grow into raindrops by continuing to condense and collide with each other and merge. Ice clouds are made of tiny ice crystals. When these small ice crystals collide with each other, the surface of the ice crystals will heat up and partially melt, and they will stick to each other and freeze again. Repeat this many times, and the ice crystals will increase in size. In addition, there is water vapor in the clouds, so ice crystals can continue to grow by condensation. However, ice clouds are generally very high and not thick. There is not much water vapor there, the growth of sublimation is very slow, and there are not many opportunities to collide with each other, so they cannot grow to a large size and form precipitation. Even if it causes precipitation, it is often evaporated on the way down and rarely falls to the ground. What is most conducive to cloud drop growth is hybrid cloud. Mixed clouds are composed of small ice crystals and supercooled water droplets. When a group of air has reached saturation for ice crystals, it has not yet reached saturation for water droplets. At this time, the water vapor in the cloud condenses onto the surface of the ice crystals, while the supercooled water droplets are evaporating. At this time, the phenomenon of ice crystals adsorbing water vapor from the supercooled water droplets occurs. In this case, the ice crystals grow very quickly. In addition, supercooled water is very unstable. Touch it and it will freeze. Therefore, in mixed clouds, when supercooled water droplets collide with ice crystals, they will freeze and adhere to the surface of the ice crystals, causing them to grow rapidly. When the small ice crystals grow large enough to overcome the resistance and buoyancy of the air, they fall to the ground and become snowflakes. In early spring and late autumn, the air close to the ground is above 0°C, but this layer of air is not thick and the temperature is not very high, which causes the snowflakes to fall to the ground before they can completely melt. This is called wet snow, or both rain and snow. This phenomenon is called "sleet" in meteorology. Similarly, the size of snow is also classified according to precipitation. Snow can be divided into three categories: light snow, medium snow and heavy snow. See Table 3 for details. Table 3. Standard types of precipitation for various types of snow. Light snow, medium snow, heavy snow. 24-hour precipitation 2.5 or less 2.6 -5.0 greater than 5.0 12-hour precipitation below 1.0 1.1-3.0 greater than 3.0 For those who have never been to a glacier, it is difficult to imagine that there are lakes of all sizes on the surface of the glacier. In fact, ice lakes are common on some larger glaciers. Ice Lakes Why do lakes appear on glaciers? There are three main forms of formation of ice lakes. One is that the subglacial channels on the glacier melt and erode the glacier, creating huge caves or tunnels. The top of the cave collapses, forming a deeper and larger long lake. One is formed by the accumulation of water in the depression of the glacier, which produces strong melt erosion in summer. In addition, the rugged peaks around the glacier often shed rock fragments. If larger rocks cover the glacier, causing differential ablation, ice mushrooms of varying sizes can grow. If the collapsed rocks are small, they will melt when heated in the sun. As a result, the rocks sink into the ice and form a cylindrical ice cup. Ice cups form quickly, forming large and small pools of water on the ice surface. During the melting period in summer, the temperature of the water in the ice surface is relatively high, sometimes reaching 5°C. Therefore, the melting effect of accumulated water is strong, which can gradually fuse the honeycomb-shaped ice cups together to form a wide and shallow ice lake. The ice lake adds a more colorful scenery to the glacier scenery. In summer, whenever the sun rises or sets, the rosy rays of light on the clear blue lake are dazzling and dazzling. Ice Cave Ice Cave In summer, glaciers are often in a state of melting.

There are three types of glacier melting: subglacial melting, intraglacial melting and ice surface melting. The Earth's crust often continuously transports heat to the base of the glacier, causing subglacial melting. However, subglacial melting is insignificant for huge glacier bodies. When meltwater from the ice surface flows into the interior of the glacier along glacier crevices, intraglacial ablation occurs. The result of intra-glacial ablation has given birth to many unique glacial karst phenomena, such as ice funnels, ice wells, ice tunnels and ice caves (we know that the stone forest in Guilin is formed by karst landforms, and the glacial landforms caused by intra-glacial ablation are very Like karst landforms, glaciologists call this glacier form karst glacier). Ice stalactites Meltwater on glaciers often forms a branch-like network of small rivers during the flow process, sometimes twisting and turning, and sometimes diving into the ice.

In some melt...>>

Question 10: Why do you feel so quiet after snowing? Because the loose and porous structure of newly fallen snow can cause sound waves to be reflected multiple times inside, thereby reducing the sound.

When a piece of snow falls, there will be many small gaps in the middle. After the sound waves enter, Reflection, reflection, reflection again, always going in and never coming out. Therefore, the structure of snowflakes can absorb sound, just like activated carbon absorbs particulate matter.

So it is very quiet when it snows.