Small knowledge of fog prevention

A little knowledge about fog 1. What do you know about fog?

If the air near the ground is cooled to a certain extent under the conditions of sufficient moisture, breeze and stable atmosphere, the moisture in the air will condense into tiny water droplets suspended in the air, which will reduce the visibility of the ground. This weather phenomenon is called fog. Fog is more common in spring from February to April. When the visibility in the atmosphere is lower than 1 km due to the condensation of suspended water vapor, meteorology calls this weather phenomenon fog.

Conditions for fog formation: cooling, humidifying and increasing water vapor content.

Fog types: 1, radiation fog 2, advection fog 3, mixed fog 4, evaporation fog 5 and smoke.

Why is the fog white?

Experiments show that when white light shines on a transparent object, the transmitted light is mainly the same color as the transparent object, and all other colors are absorbed by transparent body. If a transparent object can transmit all colors of light, then the transparent body is colorless, such as ice. But when water turns into fog, many reflecting surfaces are formed. At this time, light can't penetrate, but is reflected, that is to say, all colors of light are reflected, so the fog becomes white.

What do you know about fog?

If the air near the ground is cooled to a certain extent under the conditions of sufficient moisture, breeze and stable atmosphere, the moisture in the air will condense into tiny water droplets suspended in the air, which will reduce the visibility of the ground. This weather phenomenon is called fog.

Fog is more common in spring from February to April. When the visibility in the atmosphere is lower than 1 km due to the condensation of suspended water vapor, meteorology calls this weather phenomenon fog.

Conditions for fog formation: cooling, humidifying and increasing water vapor content. Types of fog: 1, radiation fog 2, advection fog 3, mixed fog 4, evaporation fog 5, smog Why is the fog white? Experiments show that when white light shines on a transparent object, the transmitted light is mainly the same color as the transparent object, and all other colors are absorbed by transparent body.

If a transparent object can transmit all colors of light, then the transparent body is colorless, such as ice. But when water turns into fog, many reflecting surfaces are formed.

At this time, light can't penetrate, but is reflected, that is to say, all colors of light are reflected, so the fog becomes white.

3. Knowledge of fog

The loss of ground heat will reduce the ground temperature, and at the same time, it will affect the air close to the ground, so that the temperature will also drop.

When the air is cooled to a certain extent, some water vapor in the air will condense out and become many small water droplets suspended in the air layer near the ground. If there are too many small water droplets in the air layer near the ground, which hinders people's sight, fog will form.

Because of the long nights in autumn and winter, there are not as many opportunities as Feng Yun, and the ground heat dissipation is faster than that in summer. Although sometimes the temperature during the day is similar to that in summer, the temperature at night is much lower than that in summer, so that the ground temperature drops sharply, which makes the water vapor in the air near the ground easily reach saturation in the latter half of the night and condense into small drops to form fog, so there is often fog in autumn and winter morning. .

4. Fog knowledge: How is fog formed?

Fog formation: Warm and humid air moves horizontally, passes through the cold ground or water surface, and gradually cools to form fog.

The conditions for fog formation are cooling and humidification to increase the water vapor content. In spring and autumn and rainy season, under the influence of high-pressure backflow before the arrival of the front, large-scale and long-lasting dense fog often appears.

The fog dissipates because, firstly, the fog drops evaporate due to the warming of the underlying surface; Second, the increase of wind speed will blow the fog away or lift it into clouds; Then turbulent mixing, water vapor upload, heat transfer, and evaporation of droplets near the ground.

The duration of fog is mainly related to the humidity of the local climate: generally speaking, the short fog in arid areas dissipates within 1 hour, while the long fog in humid areas is the most common and lasts for about 6 hours.

Extended data:

Types of fog:

1, radiation fog is mostly formed in rainy weather at night, mainly because radiation cooling increases the humidity of the lower layer to saturation;

2. Advection radiation fog is mostly formed on the eve of sunny to cloudy, which is mainly caused by radiation cooling and advection humidification;

3. advection fog was formed in rainy weather with high temperature and high humidity or in the early stage of rainy weather, mainly because of the high warm and humid advection humidity.

Baidu encyclopedia-dense fog

5. What are the characteristics of fog?

Generally speaking, there is a lot of fog in autumn and winter mornings. Why? We know that when the water vapor contained in the air reaches the maximum, it reaches saturation. The higher the temperature, the more water vapor is contained in the air. 1 m3 air, the maximum water vapor capacity is 6.36g at 4℃; When the temperature is 20℃, the maximum water vapor content in 1 m3 air is17.30g. If the air contains more water vapor than saturated water vapor at a certain temperature, the excess water vapor will condense out. When enough water molecules combine with tiny dust particles in the air, the water molecules themselves will combine with each other and become small water droplets or ice crystals. The water vapor in the air exceeds saturation and condenses into water droplets, which is mainly caused by the temperature drop.

If the ground heat is lost, the temperature drops and the air is quite humid, then when it is cooled to a certain extent, some water vapor in the air will condense out and become many small water droplets suspended in the air layer near the ground to form fog. Both it and clouds are caused by temperature drop, and fog can actually be said to be a cloud near the ground.

The temperature is higher during the day, so the air can hold more water vapor. But at night, the temperature drops and the capacity of water vapor in the air decreases, so some water vapor condenses into fog. Especially in autumn and winter, due to the long nights, there are not many opportunities without Feng Yun, and the ground heat dissipation is faster than that in summer, which makes the ground temperature drop sharply, so that the water vapor in the air near the ground can easily reach saturation in the middle of the night, condense into small drops and form fog. The morning temperature in autumn and winter is the lowest and the fog is the thickest.

6. Little is known about meteorology

1) Look at the proverbs that tell the sky by clouds.

1, get up early for a walk, and sun the dog at noon. 2. I'm afraid the south cloud overflows early, and I'm afraid the north cloud turns late. The cloud rises in the southeast, but if it rains, it won't last long. 4, red clouds rise at sunrise, advise you not to go far away; When the red clouds rise at sunset, it will be sunny. 5, the dark clouds are high, and there is rain; Dark clouds followed the sunset and it began to rain at night. 6. Oolong dam, it will rain if it is not cloudy. 7. The clouds are in the east, and the rain is not fierce; The clouds are in the south and the river rises. 8. There are clouds hanging in the sky and it is raining underground; Broom clouds in the sky, three days of rain; Cotton clouds in the morning will rain in the afternoon; There are clouds in the sky and thunder in the ground. 9, the northwest yellow clouds are now, hail is in sight. 10, fish scale day, it doesn't rain but it's windy. 1 1, there is no good goods in the northwest, either wind disaster or hail 1 1, dark clouds are the limelight, and white clouds are the omen of rain. 12, clouds are crossing and rain is dripping; Clouds get married, and the rain is more fierce. 13, the morning was overcast and there was no rain or wind. 14, clouds eat fog, fog eats clouds. 15, clouds heading east, gusts blowing; Where does the cloud go, wearing hemp fiber. 16, it clears up early when it rains, and it rains late until dawn. 17, there are pod clouds in the sky, and it will rain soon; There are dark clouds in the sky, and it will rain heavily soon. 18, dark clouds see the sun, and it rains in the middle of the night; Dark clouds have white feet, and there must be heavy rain; The low clouds will persist, and it will rain soon. 19, the dark clouds began to smoke and hail that day.

(2) Observing the wind and the sky proverbs

1, under the east wind all the year round, I'm afraid it won't blow much. 2. East wind rains in spring and east wind breaks in summer; The east wind in autumn is incomparable, and it snows for a long time in winter. 3, open the door, close the door. 4, the east wind rains and the east wind clears, and the east wind blows again. 5, the south wind blows to the end, and the north wind returns. 6, the east wind is urgent, the rain hits the wall, the south wind is hard, and the north wind is sharp. 7. It doesn't rain when the east wind blows dry, and it doesn't clear up when the west wind blows waterlogging. 8. The south wind turns to the east wind, and it will not fall for three days; After the rain, the southwest wind stayed for three days. 9. It rains heavily in the south wind in May and dries at the bottom of the well in June. 10, the south wind is only level 3, and it will be cloudy without rain for three days. 1 1, the east wind is wet, the west wind is dry, the north wind is cold, and the south wind is warm. 12, the wind is on the clouds, and it will be cloudy if it doesn't rain, and heavy rain will prevail. 13, it's sunny in the west and rainy in the west, and sunny in the west in the long rain. 14, the northwest wind often blows, and the weather has been good recently. 15, the east wind blows after the rain, and the rain will not stop in the future; The south wind is afraid of sunset, and the north wind is afraid of dawn. 16, fog dew in the south wind, frost in the north wind. 17, windy every night, rain and snow don't meet; If the south wind passes three times, it will be cloudy if it doesn't fall. 18, the wind is a sail, and it clears up after the rain. 19, the east wind doesn't arrive at noon, and it rings in the afternoon. The east wind is strong after the rain, and it will rain again tomorrow. 2 1, hail comes and goes with the wind, and turns around as soon as the wind blows. 22. It is windy in spring and rainy in autumn.

(C) Lightning sound and light proverbs

1, it thundered and rained early, but it didn't last long. It doesn't rain much when it thunders at the zenith, but it rains heavily when it thunders near the clouds. 3, the thunderstorm is not fierce, and the thunder is full of pits. 4, the thunder is fast and clear, and the dull thunder is difficult to clear. 5, thunder is like grinding, and the wind is mixed with hail. 6. The spring thunder on 10 is cloudy, and the winter thunder on10 is cold. 7. The sky flashes in the east, the rain flashes in the west, the fire door opens in the south, and it flashes overnight in the north. 8. The southeast is sunny and the northwest is rainy.

(4) Proverbs about observing things and the sky

1, magpies build nests high, and it rained and waterlogged that year. After a heavy rain, I heard birds singing, and the weather soon cleared up. The bird landed on the boat, and the rainy day passed. 4, the magpie branches are called, and it is sunny when going out. The crickets went to the house and the crops were blistered. 6, mosquito bites are very strange, the weather is going to get worse. 7. Dragonflies circle thousands of times, and it will rain in a few days. 8. Bees are busy picking flowers, and it will rain in a short time. 9, the waist is sore and itchy, and there is rain for a long time. 10, jujube flowers mainly control drought, and pear flowers mainly control waterlogging. 1 1. It rained for three or five days without seeing the mountains on sunny days. 12, swallows fly low, ants move, fish come for air, and heavy rain will come soon. 13, cats wash their faces, frogs call it rain. 14, mantis flying around, with showers. 15, spiders weave webs, and it will clear up after a long rain. 16, the tortoise is sweating and takes an umbrella when going out. 17, snake corridor, heavy rain. 18, bosom friend, the sky clears up.

7. Types of fog

Radiation fog, advection fog, advection radiation fog, uphill fog, steam fog, fog formed by long-distance airflow movement, fog in cold areas 1. Radiation fog radiation fog refers to the fog formed by losing heat energy through radiation, causing the temperature to drop and the water vapor to reach saturation; Radiation fog can be divided into three types according to the saturated position of water vapor: low fog, continental high inversion fog and coastal high inversion fog, and can be divided into one type of valley fog according to the special terrain needed for formation.

It is worth noting that although the radiation fog is formed on land, it usually occurs in the early hours of the morning, and if it is mixed with sea breeze, it can still be blown to the sea. Second, advection fog When warm and humid air flows horizontally through a cold surface and is cooled by contact, coupled with strong vortex mixing, a thick layer of air is cooled and water droplets are brought to a considerable height, advection fog will be formed.

Advection fog and low fog are very close to the ground. The biggest difference is that the top of advection fog has the most obvious cooling, so the fog will be thicker. Third, advection radiation fog Advection radiation fog is a kind of fog with both radiation fog and advection fog properties.

During the formation of advection radiation fog, water vapor is mainly supplied by advection at first, and the fog is regenerated by radiation cooling on the ground after night. Advection radiation fog is generally the most common cause of dense fog, especially in coastal land, such as Jian 'an Plain and Shandong Peninsula.

4. Up-hill fog Up-hill fog refers to the fog generated by cold air rising and adiabatic expansion and condensation due to terrain reasons (up-hill fog is also upgraded to expansion fog). Generally speaking, the stronger the wind pushes the air mass, the thicker the fog.

Rising fog is common in coastal mountainous or hilly areas all over the world, and its height is generally below 300 meters, but there are also higher examples. The fog on the uphill looks like a cloud on the flat ground; In mountainous areas and fog, it is easy to see rain or light snow in Mao Mao.

Fog on an uphill slope is unlikely to cause low visibility. Even if a dense fog block passes through, it will be taken away quickly because of the wind, which is not easy to cause human activities. 5. Vapor fog refers to the fog formed by saturation due to the evaporation on the water surface and the endless supply of water vapor.

Water vapor fog often appears in places with high water vapor pressure, such as summer morning or polar regions. Steam fog is closely related to the snowfall and rainfall effects in the Great Lakes in late autumn and early winter. At this time, steam fog usually merges into freezing fog or hoarfrost.

6. Precipitation particles such as water drops or snow in the air near the fog front formed by long-distance airflow fall below the clouds, so that the water points evaporate into water vapor. When water vapor condenses at the dew point, it will produce frontal fog, and when the air is saturated, it will also produce frontal fog. Frontal fog most often appears near the center of blocking cyclone and warm front, and its width is generally less than 100 km. Most of them appear in front of the warm front. Go with it.

Fog in cold regions Low temperature fog: fog formed by human activities and the release of a large number of condensation nuclei in polar regions. Low-temperature fog often lingers near human settlements at high latitudes.

Ice fog: Ice fog is produced when water spots in any fog condense into borneol. It is usually formed when the temperature is below freezing point, so it is common in the north and south poles.

Freezing fog: When the water spots in the fog solidify on the surface of an object, frost is produced. The foggy scene at this time is called freezing fog, which is common at the top of the cloud. Extended data:

Fog will reduce visibility, even to several meters in very bad conditions, which brings great inconvenience to human life.

Although some vehicles are not affected by radar, most vehicles will drive slowly in foggy weather and use more lights for lighting. The fog on the road is particularly dangerous and can easily lead to accidents.

Fog will also affect the take-off and landing of aircraft, and whether it is easy to fog will be one of the considerations before airport construction. After the airport is opened, airport managers usually take measures to disperse the fog, or improve the airport's navigation AIDS and air traffic control standards to minimize the impact.

Baidu encyclopedia-fog.

8. Little is known about meteorology

Wind level, wind level and symbol name, wind speed (m) * land image sea level wave height (m) 0 No wind 0.0-0.2 Smog is calm 0.0 1 soft wind 0.3- 1.5 Smoke shows wind direction, microwave peak has no water drop 0. 1.2 Small wind/kloc-0. Small peak not broken 0.2 3 breeze 3.4-5.4 upwind wavelet 4 breeze 5.5-7.9 blowing dust, small waves, foam peak10.05 strong wind 8.0- 10.7 small trees swaying, wave breaking foam peak 2.0 6 strong wind 10.8- 13.8. The hard-to-break peaks formed into a damaged branch with a gale of magnitude 4.0 8 17.2-20.7, and the waves grew higher with the waves. Small damaged houses were damaged with a gale of magnitude 5.5 9-20.8-24.4, and the waves rolled over the uprooted trees with a gale of magnitude 7.0 10, and roared 9.01/. The peaks are all in the form of water droplets 1 1.5 12 Hurricane 32.7-destroying huge waves, the sky is 14.0 1, and the surface is spring.

Look at the hills in spring and Haikou in winter. (Experience in observing the sky: the visibility changes and weather phenomena of clouds in Tonganxi and northern hills in winter and spring, and the visibility changes and weather phenomena of Haikou clouds in south-southeast direction in summer and autumn indicate the local weather changes in the future 12 ~ 48 hours. "Yundong" in Minnan dialect means the season of late rice growth and harvest. Spring is chilly, spring rain is continuous, and winter is dry.

Spring rain is cold, and winter rain is broken. 4, spring south and summer north, no water mill ink.

Spring in the north, summer in the south, grass pond. It was cloudy in spring, and the south wind has stopped now.

(scientific truth-it often rains when it meets cold and warm air in Ann in spring. As soon as the south wind blows, it pushes the cold air to the north, where it gets warmer and the weather tends to clear up. It rains continuously in summer, and the north wind will clear up. 7. It is windy and rainy in autumn and sunny in the northeast.

8. After the autumn, the north wind started and dried up to half a drop. 9, spring east wind, in; The east wind in summer is very hot.

10, there is easterly rain all three seasons of the year, only in summer. 1 1.

(applicable in spring rain season) 12, with long sunny nights and rainy nights. 13, south wind is warm, north wind is cold, east wind is wet, and west wind is dry.

(This shows the influence of wind direction on cold, warm, dry and wet air) 14, Bailuyuan, once every three days. 15, Egret South, Foot Pocket; White dew in the north, no spring eyes.

16, hot pole produces wind, stuffy pole produces rain. (Practical experience: Typhoon impacts mostly occur in summer and autumn when the maximum temperature is higher than 35℃, which lasts for about 5 days; In spring, summer and autumn, the temperature is high and the humidity is high, so thunderstorms are easy to occur under the sultry weather conditions. With the application of the proverb "It's warm in the day and cool in the night, and the East China Sea is dry" in summer and autumn, we can understand how cool, hot, dry and wet affect the weather changes. ) 17, the west wind doesn't last until noon, and there will be a table after noon.

(Article 17~22: Proverbs about typhoons only apply to typhoon season) 18: There will be no typhoon for three days after noon in the west wind. 19, the wind is west, and no one knows that the typhoon will come.

(Lao Nongyun:1959 The west wind was obvious around the evening of August 23, and a strong typhoon landed in Tongan in the middle of the night) 20. Tongan in the southeast, Zhangzhou in the southwest and Quanzhou in the northeast. (Affected by the typhoon, the rainfall center is located in different directions) 2 1, in June and July, there was no good north, and the head shell was flooded.

There is a northeast wind in June, and the flood is accompanied by strong wind (there is a typhoon at sea in June and July, which will affect the local area for a few days). The typhoon didn't turn south (wind), one day later.

The typhoon (wind direction) does not belong to the south, and there is still a typhoon coming. 23. I was sick and it rained again.

24, don't go out in the morning, Wan Li Road at night. 25, looking at the southeast black, hot and rainy before noon; Looking northwest at dusk, it rains at midnight.

(in the rainy season) 26. It will clear up in the west at night, and it will be fine later. There are no clouds at night, and it will be sunny the next day. It will rain in the middle of the night and it will be windy at noon.

28, the moon is dizzy, and it changes in three days. Gouges where whole pieces are missing will rain to the sea and the mountains will clear up. 29, iron ring, it will rain; The moon is surrounded by iron rings and basking in the grass.

30, dark clouds see the sun, within three days (rain). 3 1, the dark clouds see the sun, and they will not fall tomorrow or behind the sun.

32. It's sunny now, so I haven't seen you for three days. Spring, rainy season and even rainy season. There are hooks in the sky and rain in the ground.

34, fish scales, no rain and no wind. There are hooked cirrus clouds in the clear sky and cirrocumulus at the same time, which indicates that the weather system will invade in three or four days, and most of them will rain. There will be broken clouds in the morning and thunder and rain in the afternoon (often in spring and rainy season).

The clouds broke in the afternoon and it rained in the middle of the night. 36. Wayun, sunburn.

In the summer harvest season, the sky is covered with translucent cumulus clouds, which are mostly sunny under the influence of subtropical high pressure system. ) 37. The carp spot in the sky does not need to be turned over in Sunshine Valley. (Similar to 36 weather conditions) 38. There are horizontal clouds on the horizon, and it will be sunny when the wind stops tomorrow.

(Horizontal clouds refer to lenticular clouds with stable atmosphere and clear weather) 39. Dark clouds are gathering and it is raining. 40, the situation is retrograde, and the rain is about to drip.

4 1, the battery cloud in the sky, it rained for three days. (Battery cloud refers to fort cloud) 42. It's sunny in rainy days, and it's bright in all directions when there is no rain.

In rainy season, it will rain when the surrounding cumulus clouds develop. Dark clouds run through rivers and streams, and soon the rain will be "fed" Broken clouds or cumulus clouds appear at low altitude during the long drought, and it will rain soon. ) 44. The sky is covered with gray cloth, and it keeps raining.

The gloomy sky and low clouds indicate that there will be heavy precipitation soon. 45. In the blink of an eye, the wind started. 46. The stars are white and foggy. It's going to rain.

47, the stars flash fast, but also to prevent. (The old farmer's experience in surveying the sky: in the direction of the typhoon, there are stars flashing rapidly, the elevation angle of the flash zone rises, and the trillion typhoon approaches; In which direction the flash zone moves, and in which direction the trillion typhoon moves) 48. The stars shine on the pool and the rain falls.

(spring, rainy season) 49 The stars shine on the wetland, and the good days are not long. (Spring, rainy season) 50. There is no afternoon in spring fog, and tigers soak in summer fog.

5 1, foggy and sunny in the morning, foggy and rainy at night. 52. There will be fog and rain for a long time, and there will also be fog and sunshine for a long time.

53. Spring fog is thin (sunny), summer fog and rain, autumn fog and wind, and winter fog and frost. 54. A day of spring frost and three days of rain, three days of no rain and nine days of sunshine.

55. It rains early and sunny early, and it rains late (overnight). 56, heavy rain, light rain.

There is always a break when it rains, and the light rain often doesn't stop. ) 57. Autumn rain does not fall on the ridge. 58, early rainbow rain, late rainbow sunny; It's raining in the west and sunny in the east.

59. Clouds hang on sails and water flows. (In rainy season and typhoon season, convective clouds are prone to rainbow breakage, and precipitation is often strong, which is easy to cause flash floods or floods. ) 60. North flashes with barrels, and South flashes away.

(In summer, when the territory is at the edge of the 588 line of subtropical high, the lightning and thunderstorm areas in the south often move, and the lightning in the north indicates that the subtropical high is strong or even controlled.