Fog is a type of meteorological phenomenon that occurs in places with high humidity. The only difference between the clouds we see in the sky and fog is that fog occurs at ground level. There are different types of fog depending on their formation and characteristics.
In this article we are going to tell you about the different types of fog that exist, what their characteristics and formation are.
presence of fog
The appearance of fog in a particular place and time indicates that the water vapor present in the air has reached a state of saturation. The only difference between clouds and the fog we see at a certain altitude in the sky is that the latter is at ground level (a special case being clouds of the genus Stratus). In both cases, we have a hydrometeor, which consists of a suspension of tiny water droplets, usually small in size. Technically, when horizontal visibility is less than one kilometer, we refer to it as fog.
There are a variety of situations in which fog can form, but they all boil down to two main formation mechanisms: cooling and evaporation. In the first case, when the temperature drops to the dew point, a phase change from gas to liquid occurs, and fog droplets begin to form as water vapor in the air condenses. For a deeper understanding of this phenomenon, you can consult how fog forms at this link . Radiation fog, also known as irradiance fog, and advection fog are both cooling fogs, although they each have their own unique characteristics and form in different environments.
Types of fog
The typical fog that forms in the valleys and plateaus of the interior of the Iberian Peninsula, primarily during the winter months, is radiant fog. Nighttime cooling near the ground, where the air is calm in a stable atmosphere, causes these fogs to form extensive banks, and under particularly favorable conditions (previously humid and with low or very low temperatures, from 0 to 5°C), they can be especially long-lasting. These clouds are static, unlike advection fog, which is created when large amounts of warm, moist air move over an ocean or cold land. In this case, we are dealing with the typical coastal fogs that do not follow a day-night cycle and can appear at any time of year and in any season. For more information, you can consult the section on fog and its characteristics.
Evaporation mechanisms also create sea fog, like most advection fogs, but in this case, the fog forms when water vapor from a relatively warm sea surface comes into contact with the cooler air above it. This fog is common in polar seas and is known as "Arctic smoke." Evaporation is also a key process in the formation of some frontal fogs. Warm fronts sometimes produce drizzle, and, for simplicity's sake, it's common to identify both phenomena without distinguishing between drizzle, very small raindrops, and fog.
In fact, there is not much difference between the two types of meteors (drizzle and fog) as our raindrops are slightly larger than normal in the latter. Under the names of weeping fogs, meonas or chorreras, those fogs that are humid and subject to light precipitation are known.
Names given in different places
There are dozens—perhaps a hundred—of words in Spain used to refer to the regionalism of fog or mist. On the one hand, there are variants of these two terms, such as nebra, niebria, nebrÃa, niubrina, or nublina. For Asturias, words like borrina, borrÃn, or burriana were used. We also find the last word in the form gurriana, and the Cantabrian variant (guarrina), where it refers to drizzle mixed with fog.
Among the more unusual names for fog, we have taró (or tarol). Originating in Phoenicia, on the Costa del Sol and in the Campo de Gibraltar, this term refers to a very persistent sea fog that forms mainly in summer and early autumn around the Strait of Gibraltar, sometimes extending into the Alberan Sea due to inlets from Africa. Dry southerly winds evaporate a large amount of water from the sea. Ships crossing the strait must have audible signals to avoid potential collisions. To better understand the conditions that create fog, you can consult the article on surface air temperature variations.
Another unique term is dorondón. In Aragon, it refers to a very thick, cold fog, often freezing. This occurs at temperatures below 0°C (the freezing point of water), where the droplets that form the fog become supercooled (in a transitional phase called supercooling). Therefore, when they hit anything, such as posts, fences, trees, or bushes, they freeze immediately, forming a layer of ice known as frost. The result is a white landscape reminiscent of snowfall, or a landscape that produces intense frost.
We conclude our brief review of fog nomenclature with some other terms, such as macazón, used internally in Cantabria to refer to low, closed fog, but which only occupies a small plot of land (biblioteca de la niebla), boira, the enhanced boirón (Serrablo region, in Alto Aragón) and its small boirina, in Catalonia, are used to identify fog, and finally bufo or bufa, which takes its name from the low mountains of fog that rise from the valley, driven by the daytime breeze.
Other types of fog
Advection fog
Fog that forms when a mass of moist air passes over a cooler surface is called advection fog. The lower surface temperatures lead to lower temperatures in the moist air masses. This increases their relative humidity and causes the water vapor in the air to condense. For more details about this type of fog, you can consult this article on hydrometeors and their types.
evaporation mist
Evaporative fog, or cold advection fog, forms from the movement of cold, stable air over a much warmer body of water. As some of the warm water evaporates, the cold air above becomes saturated, and the water vapor condenses into cold air. This creates what is known as steam fog, sea smog, or Arctic sea smog.
mountain fog
Another type of fog is mountain fog, because the base of the cloud is lower than the mountain peak . This fog can create poor visibility in mountainous areas. It might also be interesting to learn about the different types of meteorological phenomena that influence weather events like this.
front fog
Frontal fog forms when rain comes from warm air and falls on cold, stable air. If the wind is light, the evaporation of raindrops can saturate the air near the ground, creating fog.
I hope that with this information you can learn more about the different types of fog and their characteristics.
