How's the weather?

Weather refers to the specific state of the near-surface atmosphere in a short time. Weather phenomenon refers to various natural phenomena in the atmosphere, that is, the comprehensive expression of the spatial distribution of various meteorological elements in the atmosphere (such as temperature, pressure, humidity, wind, clouds, fog, rain, snow, frost, thunder, hail, haze, etc.). ) in an instant. The weather process is the change process of weather phenomena with time in a certain area. All kinds of weather systems have certain time and space scales, and they are intertwined and influence each other. The combination of many weather systems constitutes a large-scale weather situation and hemispheric and even global atmospheric circulation. The weather system is always in the process of rebirth, development and extinction, and there are corresponding weather phenomena in different development stages.

Weather refers to the specific state of the near-surface atmosphere in a short time. Weather phenomenon refers to various natural phenomena in the atmosphere, that is, the comprehensive expression of the spatial distribution of various meteorological elements in the atmosphere (such as temperature, pressure, humidity, wind, clouds, fog, rain, snow, frost, thunder, hail, haze, etc.). ) in an instant. The weather process is the change process of weather phenomena with time in a certain area. All kinds of weather systems have certain time and space scales, and they are intertwined and influence each other. The combination of many weather systems constitutes a large-scale weather situation and hemispheric and even global atmospheric circulation. The weather system is always in the process of rebirth, development and extinction, and there are corresponding weather phenomena in different development stages.

weather

English: weather

geographic information

Weather refers to the ever-changing atmospheric state, which is not only the atmospheric state in a certain time and space, but also the continuous change of atmospheric state in a certain time interval. So it can be understood as a general term for weather phenomena and weather processes. Weather phenomenon refers to various natural phenomena in the atmosphere, that is, the comprehensive expression of the spatial distribution of various meteorological elements in the atmosphere (such as temperature, pressure, humidity, wind, clouds, fog, rain, snow, frost, thunder, hail, etc.). ) in an instant. Weather process is the change of weather phenomena with time in a certain area.

Weather landscape

Weather is the general name of atmospheric conditions (such as cold and warm, wind and rain, dry and wet, sunny and so on). ) and its changes in a short time in a certain area. Weather system usually refers to the atmospheric motion system with typical characteristics, such as high pressure, low pressure, high pressure ridge and low pressure trough, which cause the change and distribution of weather. All kinds of weather systems have certain time and space scales, and they are intertwined and influence each other. The combination of many weather systems constitutes a large-scale weather situation and hemispheric and even global atmospheric circulation.

weather

The weather system is always in the process of rebirth, development and extinction, and there are corresponding weather phenomena in different development stages. Therefore, the weather and weather changes in a region are related to the weather system and its development stage, and are the comprehensive results of atmospheric dynamic and thermal processes.

All kinds of weather systems are formed, developed and evolved in a certain atmospheric circulation and geographical environment, and all reflect the environmental characteristics of a certain region. For example, the polar regions and their surroundings are covered with ice and snow all year round, and the air is cold and dry. This unique geographical environment has become the background condition for the formation and development of polar low-altitude cold high pressure and high-altitude polar vortex and low trough. It is a necessary condition for the emergence and development of convective weather system that the equatorial and low latitudes are hot and humid all the year round and the atmosphere is unstable. Mid-high latitudes are areas where cold and warm air currents often cross. Cold and warm air masses not only come and go frequently, but also have unstable baroclinic, which is an important basis for the formation and development of frontal and cyclone systems. The formation and activities of weather system will in turn have a profound impact on the structure and evolution of geographical environment. Therefore, understanding the formation, structure, movement and change of weather system and its relationship with geographical environment is of great significance for understanding the formation, characteristics and change of weather and climate and predicting the evolution of geographical environment.

Weather forecast is a science that human beings predict the weather development. From proverbs to the calculation of Naville-Stokes equation by computer, numerical prediction has a long history. Today's weather forecast can make a more accurate forecast of the weather in a week. At present, most gas forecasts broadcast the highest and lowest temperatures; Rainfall probability, rainfall; Sunny, cloudy, ultraviolet index, cold index and so on.

The "moisture regain" weather cleverly prevents moisture and minimizes the indoor and outdoor temperature difference.

Experts say that this "resurgence" weather is conducive to the growth and reproduction of bacteria, and it is easy to make food, clothing, furniture and other items moldy. Use heaters, electric ovens and other heat source equipment to heat the room so that the indoor temperature is equal to or slightly higher than the outdoor temperature; The second is to try to isolate the invasion of warm and humid air. Use equipment with dehumidification function.

It is rainy in spring, often for several days or even ten days. And at this time, as long as the weather turns to "southerly weather", the floors and walls with tiles and the painted furniture surfaces will be wet and sweaty. This is a typical "resurgence" phenomenon.

In the face of humid weather, the following measures can be taken to prevent or reduce it: First, try to reduce the temperature difference between indoor and outdoor. Use heating, electric oven and other heat sources.

Get wet

Prepare to heat the room so that the indoor temperature is equal to or slightly higher than the outdoor temperature; The second is to try to isolate the invasion of warm and humid air. Once the wind turns from north to south, doors and windows should be closed in time, and indoor wardrobes and cupboard doors should also be closed to reduce the entry of warm and humid outdoor air; The third is to put some hygroscopic substances indoors. More economical and ideal is quicklime (massive lime), which absorbs water vapor in the air and releases heat when it melts, which has a heating effect on the room; The fourth is to use equipment for dehumidification. The air conditioner with dehumidification function should be turned on immediately; Conditional dehumidifiers can also be used to filter indoor air for dehydration.

Main weather elements: wind, clouds, fog, rain, snow, frost, thunder, hail, etc.

Two weather types

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Sunny cloudy cloudy cloudy shower Thundershower Thundershower accompanied by hail, sleet, light rain, heavy rain, heavy rain, heavy rain, heavy rain, heavy snow, heavy snow, heavy fog, freezing rain, sandstorm, small to moderate rain, heavy rain, heavy rain, heavy rain and heavy rain, small to moderate rain, heavy snow, floating dust, strong sand storm, sunny to cloudy, cloudy to cloudy, foggy.

force 3 wind

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The cause of wind

The direct cause of the wind is the uneven distribution of air pressure in the horizontal direction. Wind is influenced by different factors such as atmospheric circulation, topography and water area.

wind

The comprehensive influence is manifested in various forms such as monsoon, local sea-land wind, valley wind and foehn wind. Simply put, wind is the directional movement of air molecules. To understand the causes of wind, we must first understand two key concepts: air and air pressure. The components of air include nitrogen molecules (accounting for 78% of the total air volume), oxygen molecules (accounting for about 2 1%), water vapor and other trace components. All air molecules are moving at a very fast speed, colliding with each other and anything on the horizon.

atmospheric pressure

It can be defined as the pressure exerted by air molecules in a given area. Generally speaking, the more air molecules exist in an area, the greater the air pressure in this area. Accordingly, wind is the result of pressure gradient force. However, some changes in atmospheric pressure are caused by storms, some are caused by uneven surface heating, and some are caused by atmospheric molecules being forced to flow out from areas with relatively high atmospheric pressure in a certain horizontal area.

Several basic types of pressure field

Caused by the low pressure area. Most of the high-pressure and low-pressure belts shown on the weather map only form a mild breeze that accompanies us. However, the pressure difference required to generate the breeze only accounts for 1% of the atmospheric pressure itself, and this pressure change will occur in many areas. Relatively speaking, the formation of strong storms stems from the change of larger and more concentrated pressure areas.

The influence of the wind

Wind is one of the environmental factors of agricultural production. Moderate wind speed plays an important role in improving farmland environmental conditions. The increase of wind speed accelerates or strengthens the surface heat exchange, evapotranspiration of farmland and the transportation of carbon dioxide and oxygen in the air. Wind can spread plant pollen and seeds and help plants grow.

wind

Pollination and reproduction. Wind energy is widely distributed and inexhaustible. Monsoon prevails in China, which is beneficial to the growth of crops. Inner Mongolia Plateau, Northeast Plain, Southeast Coast and Inland Mountainous Area are rich in wind energy resources, which can be used as energy sources.

Wind will also have a negative impact on agriculture. It can spread pathogens and plant diseases. High-altitude wind is a meteorological condition for the long-distance migration of pests such as armyworm, rice planthopper, rice leaf roller and locust. Strong wind causes mechanical wear of leaves, lodging of crops, broken trees, falling flowers and fruits, which affects the yield. Strong winds can also lead to soil erosion and sand dune movement, and destroy farmland. Blindly reclaiming wasteland in arid areas, wind will lead to land desertification. Strong winds and snowstorms in pastoral areas will disperse herds and aggravate freezing damage. Some special properties of local winds often cause wind disasters. Tidal wind with high salinity, scorching wind with high temperature and low temperature, and dry-hot wind blowing from the sea have seriously affected the flowering and fruiting of fruit trees and the filling of cereal crops. In order to prevent wind damage, wind-resistant varieties with dwarfing, lodging resistance and friction resistance are usually cultivated. It is more effective to build windbreaks and set up windbreaks.

wind energy

The kinetic energy formed by airflow is wind energy. Wind energy is a conversion form of solar energy.

The radiation of the sun causes uneven heating of the earth's surface, uneven distribution of atmospheric pressure, and the air moves along the horizontal direction to form wind. The formation of wind is the result of air flow. The formation of wind energy utilization is mainly to convert the kinetic energy of atmospheric movement into other forms of energy. In the equatorial and low latitudes, the solar altitude angle is large, the sunshine time is long, the solar radiation intensity is strong, the ground and atmosphere receive more heat and the temperature is high; At higher latitudes, the solar altitude angle is small, the sunshine time is short, the heat received by the ground and the atmosphere is less, and the temperature is low. This temperature difference between high latitude and low latitude forms a north-south pressure gradient, which makes the air move horizontally and the wind blows along the direction of the horizontal pressure gradient, that is, the vertical and isobars blow from high pressure to low pressure. The earth is spinning, and the force that deflects the horizontal movement of air is called geostrophic deflection force, which deflects the airflow in the northern hemisphere to the right and the airflow in the southern hemisphere to the right, so the atmospheric movement of the earth is not only affected by the pressure gradient force, but also by geostrophic deflection. The real motion of the atmosphere is the result of the comprehensive influence of these two forces.

In fact, the sea surface wind is not only dominated by these two forces, but also influenced by the ocean and topography to a great extent. Mountain passes and straits can change the direction of airflow and increase the wind speed, while hills and mountains rub against each other and reduce the wind speed, while isolated peaks increase the wind speed because of their high altitude. Therefore, the temporal and spatial distribution of wind direction and wind speed is more complicated.

In winter, the mainland is colder than the ocean, and the pressure on the mainland is higher than the ocean. The wind blows from the mainland to the sea. In summer, on the other hand, the mainland is hotter than the ocean, and the wind blows inland from the ocean. This seasonal wind is called monsoon. The so-called land-sea breeze is that during the day, the air flow on the mainland is heated and expanded, rises to high altitude and flows to the ocean, and then cools and sinks over the ocean. The air flow near the surface of the ocean blows to the mainland to compensate for the rising air flow from the mainland. The low-level wind blows from the ocean to the mainland, which is called sea breeze. At night (winter), on the other hand, the low-level wind blows from the mainland to the ocean, which is called land wind. In mountainous areas, due to thermal reasons, it blows from the valley to the plain or hillside during the day and from the plain or hillside at night. The former is called valley wind and the latter is called mountain wind. This is because the hillside heats up quickly during the day, and the temperature is higher than the air temperature at the same height above the valley. The warm air on the hillside flows from the hillside to the valley, and the air in the valley supplements the air lost along the hillside. At this time, the wind blowing from the valley to the hillside is called valley wind. At night, the hillside is cooled by radiation, which is faster than the air at the same height. Cold air flows into the valley along the hillside, which is called mountain wind. When solar radiation can pass through the earth's atmosphere, the energy absorbed by the atmosphere is about 2 * 10 16W, and a small part of it is converted into kinetic energy of air. Because the tropics absorb more solar radiation energy than the polar regions, the atmospheric pressure difference leads to airflow and "wind". As for local areas, such as high mountains and deep valleys, the air at the top of the mountain is heated by sunlight during the day, and the cold air in the deep valleys takes its place, so the wind blows from the deep valleys to the mountains; At night, the air on the mountain dissipates quickly, so the wind blows from the mountain to the deep valley. For another example, in coastal areas, due to the temperature difference between land and ocean during the day, sea breeze blows to land; On the contrary, the land wind blows to the sea at night.

Classification of wind

Wind speed refers to the horizontal distance of air flow per unit time. According to the phenomenon caused by the wind to the ground objects, the wind is divided into 13 grades, which are called wind grades. Record with a number of 0 ~ 12.

Wind level Wind level and symbol name Wind speed (m) * Land image sea surface wave height (m) wind

0 No wind, 0.0-0.2 smoke, straight up, calm, 0.0

1 soft wind 0.3- 1.5 smoke indicates that the wind direction is at the peak of microwave 0. 1 and there is no water drop.

weather

2 breeze 1.6-3.3 Feel the wind, and the small wave crest will not be broken by 0.2.

3 breeze 3.4-5.4 standard propagation wavelet peak rupture 0.6

4 breeze 5.5-7.9 blows dust, small waves, foam peak 1.0.

5 Strong breeze 8.0- 10.7 Waves and foam peaks in swaying young trees 2.0

6 strong wind 10.8- 13.8 wire sound waves to water droplets 3.0

7 gale 13.9- 17. 1 difficulty in walking, peak breaking, foam strips 4.0

8 strong wind 17.2-20.7 damaged branches, wave 5.5.

9-level gale 20.8-24.4 Small damaged houses wave crest rollback 7.0

10 gale 24.5-28.4 uprooting trees, waves rolling and roaring 9.0

1 1 Storm 28.5-32.6 was generally damaged, and the peaks were all in water droplets 1 1.5.

12 typhoon 32.7- destructive waves +04.0

Note: The wind speed listed in this table refers to the wind speed value at10m above the flat ground.

wind direction

Wind direction refers to the direction in which the wind blows. For example, the north wind refers to the air flowing from north to south. Wind direction is generally expressed in eight directions. They are: North, Northeast, East, Southeast, South, Southwest, West and Northwest.

Ordinary wind

Gust: When the flow speed of air is up and down, the wind will be up and down, and there will be waves of feeling when blowing on people. It's called a gust.

Cyclone: It is a cyclone when the air flies in the air with dust to form a vortex.

Foehn: When the air crosses the ridge, it is easy to produce dry and hot wind on the leeward side, which is called Foehn.

tornado

Tornado: A tornado is a circular column of air that rotates violently. From a distance, it looks like an elephant's nose that keeps swinging or a python hanging in the air.

Song of the wind

The zero-level smoke column goes straight into the sky, the first-level light smoke blows in the face with the wind, and the second-level light wind.

Three-level red flag exhibition with moving leaves, four-level flying paper with shaking branches, and five-level small trees with shaking leaves

It is difficult to walk with an umbrella at level 6, inconvenient to walk in the wind at level 7, and the branches at level 8 are blown off by the wind.

Nine-level roof flying tiles and ten-level uprooting trees and toppling houses are rare on land.

cloud

The origin of clouds

People are no strangers to clouds. White in sunny days and black in rainy days are called clouds. They make the sky unpredictable. People often see that the sky is sometimes blue and cloudless, sometimes white clouds are blooming, and sometimes dark clouds are gathering. Why sometimes there are clouds in the sky and sometimes there are no clouds? How are clouds formed? What is it made of?

cloud

Clouds floating in the sky are composed of many tiny water droplets or ice crystals, some of which are mixed together. Sometimes it also contains some big raindrops and ice particles. The bottom of the cloud does not touch the ground and has a certain thickness.

The formation of clouds is mainly caused by water vapor condensation.

More than ten kilometers from the ground, the closer to the ground, the higher the temperature and the denser the air; The higher the altitude, the lower the temperature and the thinner the air.

On the other hand, the water surface of rivers, lakes and seas, as well as the moisture of soil, animals and plants, evaporate into the air at any time and become water vapor. After water vapor enters the atmosphere, it turns into clouds to cause rainfall, or condenses into frost dew, and then returns to the ground, permeates the soil or flows into rivers, lakes and seas. Later it will evaporate (vaporize) and then condense (condense) and drop. It goes on and on.

After the water vapor enters the lower atmosphere from the evaporation surface, the temperature here is high and there is much water vapor. If the hot and humid air is lifted, the temperature will gradually decrease, and when it reaches a certain height, the water vapor in the air will reach saturation. If the air continues to be lifted, there will be excess water vapor. If the temperature there is higher than 0℃, the excess water vapor will condense into small water droplets; If the temperature is lower than 0℃, excess water vapor will condense into small ice crystals. When these small water droplets and small ice crystals gradually increase to a level that can be recognized by human eyes, it is a cloud. The process of cloud formation is a process in which water vapor in the air reaches saturation or supersaturation through various reasons and condenses. Water vapor saturation in the air is a necessary condition for cloud formation. The main ways are as follows:

(1) The water vapor content is unchanged, and the air is cooled.

(2) When the temperature is constant, the water vapor content increases.

(3) Not only the water vapor content is increased, but also the temperature is reduced.

But for the formation of clouds, the cooling process is the most important process. In the process of cooling, the cooling effect brought by ascending movement is the most common.

Genetic classification of clouds

Clouds form where moist air rises and meets cold air. This may happen in the following situations:

cloud

cloud

The warm air mass on the front cloud rises into a cloud.

Topographic clouds When the air rises along the positive terrain,

When the air mass passes through a cold underlying surface, such as a cold water body, advection clouds are formed.

Clouds produced by air convection.

Clouds generated by updraft in the center of cyclone.

Morphological classification of clouds

Simply put, there are three main forms of clouds: large cumulus clouds, large stratus clouds and fibrous cirrus clouds.

The scientific classification of clouds was first proposed by the French naturalist JeanLamarck in 180 1 year. 1929, according to the classification made by British scientist LukeHoward in 1803, the international meteorological organization divided clouds into ten major cloud genera according to their shapes, components and formation reasons. These ten cloud genera can be divided into three cloud systems according to the height of cloud bottom: high cloud system, middle cloud system and low cloud system. Another classification separates cumulonimbus and cumulonimbus from the low cloud family, which is called the straight cloud family. The cloud base height used here is only applicable to mid-latitude areas. (In addition to Britain and the United States, countries such as the World Gas Organization generally adopt the international system of units. )

High clouds: High clouds are formed at an altitude of more than 6 kilometers, in the colder part of the troposphere. It belongs to three genera, all cirrus. At this height, water will solidify and crystallize, so this group of clouds is all made up of ice crystals. High clouds are generally fibrous, thin and mostly transparent.

Cirrus cloud (Ci): The cloud body is fibrous, white, shadowless and shiny, yellow or red before sunrise and after sunset, with thick clouds.

cirrus

It's grayish white. Cirrus clouds are divided into four categories:

Cirrus clouds (Cs fil): Clouds are dispersed and the fiber structure is clear, such as tangled filaments, feathers, tails, etc.

Ci dens: Clouds are dense and aggregated.

Cirrus: Clouds are arranged in parallel with small hooks at the top, similar to commas.

Pseudocumulonimbus: The ice crystal part at the top of cumulonimbus has been separated from the parent body. Clouds are large and dense, often anvil-shaped.

Cirrostratus (Cs): Clouds are all layered, transparent or milky white. Through the clouds, the outlines of the sun and the moon can be clearly seen. Objects on the ground have shadows and are often dizzy. Cirrostratus can be divided into two categories:

Jun cirrostratus: The cloud curtain is thin and uniform, and no obvious structure can be seen.

Mao cirrostratus: The thickness of the cloud curtain is uneven, and the filamentary fiber structure is obvious.

Circurumus (Cc,): Clouds are very small, with white scales and flakes, which are often arranged in rows or groups, like small ripples caused by a breeze blowing over the water. Convolution flowers have only 1 categories.

Mesospheric cloud

Zhongyunzu

Clouds form at a height of 2500 to 6000 meters. They are made up of excessively frozen water droplets.

As (high-level cloud): Clouds are evenly layered, grayish white or gray, covering the whole day. High-level clouds can be divided into two categories:

Transparent high-level cloud: the cloud is very thin, uniform in thickness, grayish white, and the outline of the sun and the moon is blurred, like a layer of ground glass.

For example, op: The clouds are thick and completely gray, and the striped structure of alternating light and dark can be seen at the bottom, which covers the sun and moon, but the outline can't be seen.

Ac (altocumulus): Clouds are small and well-defined. Thin clouds are white and can see the outline of the sun and the moon; Thick clouds and gray, the outline of the sun and the moon is indisputable. Flat, tile-shaped, fish-scale or wavy dense cloud bands. Arrange in groups, rows and waves in one or two directions. Cumulus clouds can be divided into six categories:

Translucent cumulus clouds: the clouds are thin, the individuals are separated and arranged neatly, and the blue sky can be seen in the cracks of the clouds; Even if there is no gap, the thin part of the cloud is brighter.

Shadow altocumulus (Ac op): Clouds are thick and densely arranged, and there is no gap between them, so it is difficult to distinguish the positions of the sun and the moon.

Podoid cumulus: Clouds are white, thick in the middle, thin in the edge, well-defined, isolated and scattered, and shaped like pods or lemons.

Ac cast: The bottom of the cloud is flat, and the top protrudes into several small cloud towers, similar to a castle in the distance.

Cumulus cloud: the edge of the cloud is broken, much like broken cotton wool.

Cumulonimbus Altocumulus (Ac cug): Clouds of different sizes are grayish white with a slight appearance of cumulonimbus, which is formed by the expansion of decaying cumulonimbus or cumulonimbus.

Low cloud group: including stratocumulus, stratocumulus, nimbostratus, cumulonimbus and cumulonimbus, in which stratocumulus, stratocumulus and nimbostratus are composed of water droplets, and the height of cloud bottom is usually below 2500m. Most low clouds are likely to rain, and there is often continuous rain and snow in nimbostratus. Cumulonimbus clouds and cumulonimbus clouds are composed of water droplets, supercooled water droplets and ice crystals. The height of the cloud bottom is usually below 2500 meters, but the cloud top is very high. Cumulonimbus clouds often have thunderstorms, sometimes accompanied by strong winds and hail.

Stratocumulus (Sc): Clouds are generally large, with great differences in thickness or shape, often gray or grayish white, and loose structure. Thin clouds can distinguish the position of the sun and the moon; Thick clouds are darker. Sometimes scattered, mostly in groups, rows and waves, neatly arranged in one or two directions. Stratocumulus can be divided into five categories:

Translucent stratocumulus: The clouds are thin, grayish white, arranged neatly, and the blue sky can be seen at the gap. Even without gaps, the edge of the cloud is bright.

Shadow stratocumulus: the cloud is very thick; Dark gray, seamless between clouds, often layered, all day, with obvious ups and downs at the bottom.

Cumulonimbus stratocumulus: Clouds vary in size, showing gray or dark gray stripes, with cumulonimbus characteristics at the top, which are flattened by descending cumulonimbus or cumulonimbus.

Lenticular stratocumulus: Clouds are flat, which are often directly formed by the rising of scattered heated air on the ground in the evening.

Stratocumulus Fort: The top of the cloud is protruding, and the bottom of the cloud is connected with a horizontal line, similar to a castle in the distance.

Stratus (St): Clouds are all layered, gray and foggy, but they are not connected with the ground and often cover the mountainside. Stratospheric clouds can be divided into two categories:

Layered clouds: Clouds are all layered, gray and foggy, but they are not connected with the ground and often cover the mountainside.

Stratocumulus (Fs): Broken stratocumulus fragments formed by stratocumulus splitting or fog lifting.

Nimbostratus (Ns, Nimbostratus): Clouds are evenly layered, covering the whole day, completely blocking the sun and the moon, and are dark gray. The cloud bottom is often accompanied by broken rain clouds, which reduces the continuous rain and snow. Nimbostratus can be divided into two categories:

Nimbostratus: The clouds are evenly layered, covering the whole day, completely covering the sun and the moon, and are dark gray. The bottom of the clouds is often accompanied by broken rain clouds, which brings continuous rain and snow weather.

Broken rain clouds: Clouds are low and broken, with changeable shapes and gray or dark gray. They often appear under nimbostratus, cumulonimbus clouds and sheltered high-level clouds, and are formed by evaporation of precipitation and condensation of air humidity.

Direct exhibition cloud family

Direct clouds have a very strong updraft, so they can grow higher from the bottom. Cumulonimbus clouds of rainstorms and thunderstorms can start at a height close to the ground and then develop to a height of 75,000 feet. At the bottom of the cumulonimbus cloud, when the falling cold air meets the rising warm air, it will form a breast-like cloud like a pouch. When the cumulonimbus cloud expands, it will form a thin dome-shaped cloud at the top.

Cumulus (Cu, Cumulus): The individual is obvious, the bottom is flat, the top is convex, and the clouds are discontinuous. The light receiving part of the cloud is white and bright, and the bottom of the cloud is dark. Cumulus clouds can be divided into three categories:

Cu hum: small, clear outline, flat bottom, curved convex top, like steamed bread, less than horizontal width.

Cumulus: The individual is tall, with clear outline, flat and dark bottom, overlapping arc-shaped tops, like cauliflower, and the thickness exceeds the horizontal width.

Broken Cumulus Cloud (Fc): Small in size, incomplete in outline and changeable in shape, mostly white fragments, broken or primary cumulus clouds.

Cumulonimbus cloud (Cb): The cloud is very thick, and it is as big as a towering mountain. The top began to freeze, with vague outline and fibrous structure. The bottom is very dark, and there are often rain banners and broken rain clouds. Cumulonimbus clouds can be divided into two categories:

Bare cumulonimbus cloud: The top of the cloud begins to freeze, with overlapping arcs and vague outlines, but it has not yet spread outward.

Bristle Cumulonimbus Cloud (Cb cap): The top of the cloud has white filamentary fiber structure, which expands into horsehair or anvil shape, and the bottom of the cloud is dark and chaotic.

other

The condensation trail refers to the slender thin cloud formed when the jet plane passes at high altitude.

Noctilucent clouds are very rare. They are formed in the middle layer of the atmosphere and can only be seen at high latitudes.

Each kind of cloud has its particularity, but it is not static. Under certain conditions, this cloud can be transformed into that cloud, and that cloud can be transformed into another cloud. For example, light cumulus clouds can develop into thick cumulus clouds and then into cumulonimbus clouds; The top of the cumulonimbus cloud breaks away and becomes a pseudo volume.

noctilucent clouds

It has long been recognized that weather changes can be predicted by observation. 1802, British naturalist luke howard put forward the famous classification of clouds, which made it more accurate to observe clouds and measure weather. Howard divided clouds into three categories: cumulus, stratus and cirrus. These three types of clouds, together with the words for height and rainfall, produce ten basic types of clouds. According to these cloud phases, people have some reliable experience in forecasting the weather changes in the future 12 hours. For example, if the fluffy cumulus clouds are very scattered, it can be said that it is good weather, but if the clouds expand or have new development, it means that there will be a sudden rainstorm.

The lightest and tallest clouds are called cirrus clouds. This kind of cloud is very thin, through which sunlight can shine on the ground, and the light and shadow of houses and trees are still very clear. Cirrus clouds are constantly floating, sometimes like a white feather, sometimes like a white silk thread. If cirrus clouds are arranged in a row in the air, like fish scale waves caused by a breeze blowing over the water, it becomes cirrus clouds. Cirrus clouds and cirrocumulus are very high, where there is little water, which generally does not bring rain and snow. There is also a kind of white clouds like cotton balls, called cumulus clouds. They are often scattered in the sky about two kilometers, reflecting the bright sunshine, and the clouds are surrounded by golden brilliance. Cumulus clouds appear in the morning, most in the afternoon, and gradually dissipate in the evening. On sunny days, we occasionally see a kind of cumulus. Altocumulus clouds are groups of oblate clouds, which are arranged in a balanced way, with a blue sky in the middle, which looks like snow-white sheep on the grassland from a distance. Cirrus, cirrocumulus, Cumulus and Cumulus are all beautiful.

When the continuous rain and snow came, cirrus clouds were gathering, and a thin layer of clouds gradually appeared in the sky, as if covered with a white silk curtain. This cloud is called cirrostratus. Cirrostratus is advancing slowly, and the weather will turn cloudy. Then, the clouds are getting lower and thicker. Looking at the sun or the moon through clouds is like looking through a layer of ground glass. At this point, the scroll tower has been renamed. It's time to call it a high-level cloud. There are high clouds, and it often rains or snows within a few hours. Finally, the clouds are getting lower and thicker, the sun and the moon are hidden, and the sky is covered with dark gray clouds. This cloud is called nimbostratus. As soon as nimbostratus was formed, continuous rain and snow came.

In summer, before a thunderstorm, cumulus clouds are first seen in the sky. Cumulonimbus clouds become cumulonimbus clouds if they swell up quickly to form tall Yunshan, and the peaks compete with each other and go straight to the zenith. The cumulonimbus cloud grows higher and higher, the cloud bottom gradually turns black, and the Yunfeng gradually blurs. Soon, the whole Yunshan collapsed and dark clouds filled the sky. In an instant, thunder rumbled and thundered, and then it rained heavily, sometimes bringing hail or tornadoes.

We can also infer the weather from the brilliant phenomena on the clouds. Around the sun and the moon, sometimes beautiful colored apertures appear, the inner layer is red and the outer layer is purple. This aperture is called halo. Solar and lunar halos often appear on the cirrostratus, and the high-rise clouds behind cirrostratus and nimbostratus are signs of heavy rain. So there is a saying that the sun is dizzy in the middle of the night and the moon is dizzy at noon. It means that when cirrostratus appears, with dizziness, the weather will get worse. There is also a colored halo smaller than the halo, called "Hua". The arrangement of colors is purple and red, just the opposite of halo. Rihua and Yuehua are mostly produced at the edge of cumulus clouds. From small to large in central China, the weather tends to be fine. The central region of China is getting smaller from big to small, and the weather may turn rainy. In summer, after the rain clears, a colorful arc is often hung on the cloud curtain opposite the sun. This is a rainbow. People often say: "The east rainbow thunders and the west rainbow rains." If the rainbow is in the east, it will thunder and not rain; The rainbow is in the west and there will be heavy rain. There is also a cloud color, which often appears in the early morning or evening. The sun shone all over the sky and dyed the clouds red. This cloud is called Xia Xia. The morning glow is in the west, indicating that rainy weather is attacking us; The sunset glow in the east means that the weather has been fine in recent days. Therefore, there is a proverb "Don't go out at sunrise, but go to Wan Li Road at sunset".

Clouds absorb heat from the ground and reflect it back, which helps to keep the earth warm. However, clouds also reflect sunlight directly back into space, which has a cooling effect. Which effect is dominant depends on the shape and location of the cloud.