Where is fog most common? Why does fog occur? What types of fogs are there? How is steam mist formed?
How is fog formed? and why does it occur?
- I can copy it too, but you can’t write it briefly
WHAT IS FOG? Fog is something like a veil of tiny drops of water, sometimes mixed with smoke and dust. Sometimes the fog is so thick that it is very difficult, even impossible, to see anything, as if the clouds had descended to the ground.
Numerous weather may cause fog to form. This can happen, for example, when hot air filled with water vapor comes into contact with cooler air at ground level. The water vapor cools and condenses, forming so many tiny droplets of water that refract the light and give that opaque and slightly milky color characteristic of this phenomenon.
It is therefore unusual to see fog as it rises slowly from rivers, lake or swamp areas and in particularly wet valleys where the air contains large quantity water vapor formed during the day due to the evaporation of water. At night and early morning, cold air falls to the ground and causes the water vapor to condense into many small droplets when the dew point is reached.
Fog forms when air cools and water vapor turns into water droplets. Over the sea, fog occurs when the air is warmer than the water.
- no, they just asked why they are formed, not what it is
- Fog is a cloud near the surface of the earth. There is no difference between fog and cloud in the sky. When a cloud is near the surface of the earth or sea, we call it fog.
Fog usually forms at night and early in the morning in lowlands and over water bodies. It is associated with a cold flow of air that descends onto the warm surfaces of land or water.
Depending on the cooling at once, the fog can take several names. The one described above is referred to as "evaporative fog" and tends to be most common between fall and winter. "Irradiation fog" is usually autumnal, exhausted in the early morning and caused by cooling of the soil after sunset under clear sky conditions. The heat generated in the air closest to the ground leads to condensation and therefore fog, usually light and not very opaque.
From a fascinating meteorological phenomenon, fog can turn into a dangerous enemy, especially for those driving a car. In addition to slowing down in the event of fog, it is always advisable to: Never use high beam headlights. The lights are so intense and directly enhance the refraction phenomenon caused by the many drops of water suspended in the air, turning the fog into a white wall, impenetrable to the eye. It is better to rely on fog lights, which illuminate the road surface by directing the light downward, reducing the phenomenon of refraction.
Fogs are more common in autumn, when the air cools faster than the ground or water. In calm weather, with the onset of darkness, thin layers of fog form in low places above the ground. As the ground cools at night, the lower layers of air also become colder. When such cool air comes into contact with warm air, fog is formed.
The maximum temperature today is between 11° and 16°. Most of the day will be sunny with high clouds. In the morning hours, mainly in the western part of the Danube Plain and in some parts of the Upper Thracian Plain, it will be foggy and daily temperatures will be slightly lower. Clouds will begin to increase from the west to mid-afternoon.
Fog and heavy rain make the Struma Highway difficult to navigate. Road surfaces are wet and slippery and there is a risk of hydroplaning. Today the weather will be mostly sunny. There will also be a more significant temporary increase in cloud cover, but only some places in Western Bulgaria will soon be overtaken and overwhelmed. This is the forecast for the time of the National Institute of Meteorology and Hydrology at the Bulgarian Academy of Sciences, FOCUS announced to observer Georgi Tsekov.
As a rule, urban fogs are denser than rural ones. City air is full of dust and soot, which, when combined with water particles, form a dense blanket.
The foggiest area on Earth is the Atlantic coast of Newfoundland (Canada), where fogs are formed when moist, warm air passes over cold waters that move south from the Arctic Circle. The coldness of the water condenses the moisture in the air into small droplets of water. These droplets are not large enough to form rain. They are in the air in the form of fog.
Nakaya's work is described as a "fog sculpture". It has been working since the 1970s to create a high pressure water spray system. Rain and fog make navigation on some of the country's main roads difficult. The Dragalevtsi - Aleko road is closed and the Ministry of Internal Affairs has warned drivers not to travel to the Aleko hut. The road "Boyana - Golden Bridges", as well as Zheleznitsa - Plana, is sandy. Crews were assigned to deploy snow removal equipment to 60 designated locations in the city and be ready to treat roads.
The fog process is varied. It depends on the weather situation, season, time of day and especially local climatic conditions. The principle of fog formation is similar to the formation of clouds, but with the difference that cooling of the air to a state of saturation, when a water aerosol begins to form, occurs in the ground. If there are sufficient condensation cores, the conditions for the condensation of water vapor are created and the basic conditions for the fog itself are actually met.
But fogs in the San Francisco area form completely differently. Here the cool morning breeze blows towards the warm sand dunes, and if the day before the rain wets the sand, a dense layer of fog forms from the evaporating moisture.
Often the fog appears denser than the clouds. This is because the mist droplets are smaller in size.
Absorbs many tiny droplets more light than large drops (but in smaller quantities) that form a cloud. So it seems to us that the fogs are thicker than the clouds.
At its core, fog is similar to stratus, especially on loss and recruitment. If the base of the nimnostratum reaches the earth's surface, then we perceive it as fog. Likewise, there is loss that can cover the tops of hills and mountains. Fogs can occur within air masses, but also on atmospheric fronts. The breakdown of fog is then carried out either by the influence of surface heating in the sun, or by the current, or by a change in the synoptic situation.
Fogs formed inside air masses are divided into. Radiation fog, adjective fog fog from the evaporation of fog from the mixing of orographic fog fog fog arising from a combination of the above species. In our conditions, radiation and advection fogs or their combinations are most common. Fogs associated with the transition of the frontal systems are divided into prefrontal, frontal and frontal.
- Why are you too lazy to read?
Fog, which is especially common on the coasts, is actually a stratus cloud located directly at the earth's surface. This dense blanket of condensed water vapor results from the cooling of air containing saturated vapor.
Fog is a layered cloud on the earth's surface consisting of microscopic drops of water or ice crystals. A car driving in supercooled fog may develop a layer of ice.
Condensation of water vapor in urban environments is facilitated by high levels of dust and exhalation, especially since shortly after morning is typically the most favorable conditions for fog, peak traffic, and increased smoke production from local heaters. We distinguish between London-type smog, where smog is mainly caused by the flow of moist air from the sea, and photochemical smog, which is not associated with fog, since it consists only of harmful emissions that are produced by transport.
It is a bit simplistic and inaccurate to say that no. The difference is determined only by the position of the observer. The same meteorological phenomenon may be a cloud to one person, fog to another, and both will be right. The observer perceives the fog inside, the observer outside the cloud.
Fog forms when water vapor enters warm air or when moist air cools to a temperature lower than its dew point. The air can cool when new, even colder air invades the area. In this case, the vapor contained in the air condenses and above earth's surface fog appears of more or less significant vertical extent.
According to the Dictionary of Meteorology, fog is an atmospheric aerosol consisting of very small droplets of water or small ice crystals dispersed in the air, which reduces horizontal visibility below 1 km. A cloud is a visible system of water or ice particles in the atmosphere. For example, if the top of a mountain is hidden in clouds, it is fog to observers at the top of the mountain, but to the observer below it is a cloud.
However, there are some differences. For example, many cirrus or cirrostratus clouds, composed of very small ice crystals, are clouds to observers on the Earth's surface, but they are not foggy to viewers inside, such as on an airplane, because visibility is at least 1 km. Certain differences between cloud and fog are also how they arise. Both phenomena arise primarily from the condensation of water vapor contained in the air, either by cooling the air below its dew point temperature or by introducing more moisture into the air than can be maintained at that temperature.
There are different types of fog. They are divided depending on the processes of their formation and the place of occurrence. All classifications of fogs are more or less descriptive.
We will highlight three main types of fog here. Each of them is possible under slightly different conditions. These three types are: radiation fog, advective fog and frontal fog.
In the specific mechanisms involved, there are some differences between a typical fog on the Earth's surface and a typical cloud that only touches the Earth's surface in the mountains or in general. Typical fog occurs mainly when air comes into contact with the earth's surface. One of the most common is radiation fog or radiation fog. This is caused by the cooling of moist air from the earth's surface, which, especially on a clear night, is cooled by radiation. In summer it has a shorter duration, in autumn and winter it lasts all day.
Radiation fog. Radiation fog is also known as ground fog. This type of fog occurs when the lower layer of air quickly cools through heat exchange with the earth's surface. In this case, the surface air cools, and warmer air appears above it. If the air is still, little or no fog will form. But if there is a light wind, fog formation is very intense. However, with stronger winds, the fog dissipates due to air mixing. A light wind in the area of fog formation leads to the spread of condensation to a higher surface layer of the atmosphere. At the same time, the fog becomes denser. In the morning, when the sun's rays begin to warm the air, the fog droplets evaporate, that is, they turn into water vapor again, and the fog dissipates.
Entrained fog is created when warm, moist air moves over a colder surface. This happens in winter, for example, when warm, moist air flows towards us and snow covers the ground. This can also happen in the spring, when it is quite warm, but there are still snow islands. It can also occur in warm air over a cold surface of water, such as over a cold river, lake or sea, or when hot air flows over a colder sea. In all cases, moist air is cooled from the cold surface until its temperature drops below the dew point and condensation occurs.
In areas located at significant altitudes above sea level, radiation fog may appear on mountain slopes. Denser air flows down the slopes and forms dense and high fog in the valleys lying between the hills.
Radiation fog most often occurs in autumn and winter, when there is relatively high relative air humidity, as well as a significant length of night. Radiation fog also appears in the centers of areas of high pressure, usually characterized by light winds and cloudless skies. In relatively stable air, radiation fog that occurs in the evening or at night can persist throughout the day.
A slightly different mechanism creates evaporation fog, which, on the contrary, occurs in cold air over hot water. Hot water evaporates water into cooler air, which does not absorb as much moisture and condenses. Such fog is often found especially in autumn mornings, over lakes and larger rivers, where summer is warmer water or in winter with severe frosts over frozen water surfaces. Unlike advective fog, which lies over a cold surface or water, evaporative fog over hot water often rises like smoke.
Advective fog. Advection fog forms in air moving over an area in which the surface temperature is lower than the temperature of the advancing air. When relatively warm air moves over colder land or body of water, it quickly cools and the water vapor in it begins to condense. A thick low fog appears. In other words, vapor in the lower layer of the atmosphere quickly becomes saturated near the earth's surface, having a significant vertical extent. This type of fog can be observed at any time of the day, not just during the cold night hours.
The fog created by any of these methods can easily become cloudy. For example, radiation haze that occurs during the night may be slightly higher in the early morning hours. In the ground, visibility will increase by more than 1 km, and the raised layer will become a strata-type cloud. At the same time, however, it may take fogs for more high places, hills or hills, but also on the upper floors of buildings.
The cloud is also formed by the condensation of moisture in the air, but mainly without direct contact with the earth's surface. The main cooling mechanism is adiabatic expansion, i.e. decrease in air pressure when it moves more high levels where there is less pressure. Compressed air heats up, as we see, for example, when a tire is inflated by a pump. On the contrary, the expanding air cools. Cloudiness occurs when air escapes when the temperature under the dew drops due to adiabatic cooling.
Advective fog most often appears on the coasts, as well as in areas partially covered with snow and interspersed with snow-free areas. Such fogs are formed in cases where warm southern winds carry air to the north, i.e., to colder climatic regions.
In the northern regions Atlantic coast The United States often experiences high advective fog. They are extremely dangerous for shipping between the US, Canada and Europe. During the winter months, the main shipping lines are moved to more southern areas so that ships can avoid the fog that forms off the coast of Newfoundland.
The exit movements have different causes, and the shape of the clouds is also different. For example, cumulus clouds are caused by convection—air above a warm surface heats up, rises, and is replaced by cooler air above. In areas of material movement, individual cumulus clouds appear in areas of downward movement, free spaces between the clouds. Exit movements also occur at fronts, that is, at the boundary of air masses of different properties, in particular, different temperatures. Here, warm air rises along the boundary with cooler, heavier air, and condensation occurs again.
When advective fog occurs over the open sea, it is called sea fog. This occurs when warm air moves over a colder sea surface and is cooled by conduction. It can also appear over areas of the ocean where currents that differ noticeably in temperature pass close to each other, since the air masses above them are mixed. Sea fogs can be very long. Sometimes they do not dissipate for several weeks.
In contrast to convective clouds, frontal clouds are more contiguous, especially on a warm front, clouds of nimbostrate species develop. Another mechanism for creating exit air movement is the orographic exit. The air flow crosses a mountain obstacle, a perfectly continuous mountain ridge across the flow. On the windward side there are upward movements and cloud formation, leeward downwind movements and adiabatic compression, air warming and cloud dissolution. In humid air on the windward side, heavy rain falls; in less humid air at the top of the mountains, clouds form, even if there is a bright sky around.
In mountainous areas, slope fog may occur. This occurs when, due to adiabatic cooling, warm air encountering a mountain on its way is forced to rise along its slopes. Rapidly expanding, the rising air lowers its temperature to the dew point, which causes the appearance of thick mountain fog.
Frontal fog. Frontal fogs arise at the points of contact between two fogs with different properties. Such places are called frontal zones or proto-fronts. Fronts are very common in the atmosphere, but not all of them are necessarily accompanied by fog.
Most often, frontal fog occurs ahead of a warm front. This fog can be very long lasting. It is usually accompanied by precipitation. Frontal fogs are frequent east coast USA.
Frontal fogs also form on some areas, but less frequently than on warm ones, and not on such vast areas, which is explained by the smaller width of the zone occupied compared to warm ones.
Frontal fogs are a constant threat to all types of transport. They cause great damage when airline flights have to be canceled or flight routes have to be rerouted. Even with modern means of instrument landing, fog still remains a problem for military and civil aviation.
Fogs at sea have caused many ship collisions. They are especially dangerous on lines passing through North Atlantic where icebergs occur. The Titanic sank due to a collision with an iceberg.
In such large industrial centers as Los Angeles, New York, London, fog often mixes with smoke to form the so-called smog. Smog causes enormous harm to people's health. The mixing of thick fog with industrial smoke in industrial centers is very dangerous, especially for people with heart disease and respiratory diseases. The additional stress on the breathing and blood circulation of such patients during prolonged smog often leads to death.
Soot suspended in the air of cities and large industrial areas contributes to the formation of fog and smog. In such areas, a large number of condensation nuclei are released into the atmosphere. As a result, normal thermal conditions and air circulation are disrupted. Air pollution even affects the weather, so the temperature at night in industrial areas drops more slowly than usual.
One of the famous cases of smog with a large number of deaths occurred in London in December 1952. An inversion formed in the cold air above the city, which slowed down mixing in the ground layer of the atmosphere. Industrial smoke, which continued to enter the atmosphere, mixed with still, moisture-saturated air and formed a thick cloud with a high content of sulfur oxides over the city. This cloud was the main cause of respiratory irritation. The number of deaths per day has increased. By the middle of the first week after the smog began, nearly 1,000 deaths caused by the smog were reported. The effects of the smog were noticeable for several weeks after it cleared. Throughout this time, the number of deaths remained above normal.