Also, clouds can form at any altitude and are present in any climate whereas fog can only form at ground level and are present during cold climatic conditions only. Clouds are a mass of ice crystals or water drops suspended in the atmosphere.
They are an important part of the water cycle. There are 10 types of clouds classified into 3 different levels:. Clouds are formed when water from the ground or any water body gets evaporated in the form of water vapor by trapping the heat and leaving the water behind them cooler. There are instances where fog is formed at lower relative humidity. To begin with, the basic difference between both clouds and fog is that clouds are formed vapor is turned into liquid and takes the shape of tiny condensed particles.
Fog, on the other hand, is formed due to the cooling of ground air that turns the vapor into liquid ice or water. You can see clouds at different altitudes. You can spot them as high as 12 miles above the sea or as low as 12m above the ground.
Fog is only found on the ground level; you will never find them more than 50m above the ground. Clouds hold great significance in the atmosphere as they are responsible for precipitation and balancing the water cycle. On the other hand, Fog does not have much significance as it does not add to any phenomenon in the atmosphere. You can always see clouds in the sky irrespective of the weather conditions or seasons.
Clouds occur throughout the year, but you can find fog only during the winters. It is the time when vapor can be condensed at the ground level. The density is also a major differentiating factor that segregates clouds from the fog. Clouds have a density of 0. Clouds are denser than fog, but there are times when fog can also become dense. As clouds are part of the water cycle, they precipitate water back into the atmosphere in the form of rain.
Fog is not a part of the water cycle, so there will be no precipitation. As fog is formed at low altitudes, it cannot contribute to rain. Both fog and mist are the same thing and are formed by the condensation of vapor on the ground. You have read earlier that fog reduces visibility on the ground. The context of visibility differentiates both fog and mist.
While fog hampers visibility is less than 1, meters, the mist will reduce the visibility greater than 1, meters. Compared to fog, the mist can quickly dissipate and disappear with a slight wind. The cold breath on a chilly day can be deemed as mist.
In a nutshell, visibility is what differentiates both fog and mist, but they both are the same thing. As mentioned earlier, both cloud and fog are formed by condensation of vapor, so there will be a time when fog can turn into a cloud.
Indeed, there is a height at which fog can turn into a cloud and contribute to the water cycle. Fog is formed on the ground, and it is known as visible moisture at a height lower than 50 ft.
When this fog appears at or above 50 ft. So, 50 feet is the basic height at which fog can turn into a cloud. It is also the fine line that changes the status of both cloud and fog. For instance, when water vapor is condensed at or above 50ft. It will automatically become a cloud. Atmospheric layers with high amounts of water vapour can help to dissipate fog by long wave radiation.
Heat from the ground can lift the Fog into low cloud. Increasing shear at Fog top caused by increasing wind above the Fog increases the entrainment of dry air into the cloud and accelerates the rate of dissipation. In mature Fog the settling of droplets to the ground or onto vegetation contributes significantly to the dissipation. Solar radiation excluding mid-winter can penetrate to the ground in places where Fog is thinner such as elevated places and heat the ground and evaporate the Fog.
Consequently, heat will be convected into the cloud. During summertime due to short nights the Fog has no time to thicken long enough, before the morning sun already starts heating the ground and breaks the Fogs into patches and later maybe into fair-weather cumulus. Diagram showing the synoptic conditions for Advection Fog with front and side view panels. When moist and warm air is advected by the wind, turbulent mixing in the boundary layer moistens the air from below.
This results in advection stratus clouds. When Stratus encounters cooler waters with sea surface temperatures lower than air dewpoint temperature or cold possibly snow-covered land, turbulence and thermal convection decrease significantly, but the water vapour-driven convection from the surface continues to mix the overlying air.
This leads to cooling of the unsaturated air and lowering of the cloud base, eventually even to the formation of Advection Fog. Important factors for the formation of Advection Fog are the fetch over the sea or over land with wet snow and wind speed.
A long fetch together with not too high a wind speed allows the cloud to sink lower and eventually form Fog. Over land areas the snow temperature is an important factor: snow having below-zero temperatures can easily absorb moisture from overlying air.
This is due to the smaller water vapour pressure for ice surfaces compared to liquid water surfaces. Fog formation over dry snow is; therefore, much more common than over wet snow, as wet snow is a source of moisture. Advection Fog can be expected to be persistent, since the synoptic situation does not change rapidly. In wintertime warm sectors the middle and upper troposphere normally remain relatively dry, which favours extensive low level cloud decks to persist.
The advection of sea Fog over warmer water can also lead to lifted stratus and possibly dispersal of cloud. Advection Fog has the same tendency to shrink from the outer edges as Radiation Fog, but the advection of the clouds has to be taken into account.
Brighter spots indicating thicker and more persistent cloud may be carried downwind, while the upwind edges of clouds will clear more rapidly. Height contours at hPa: High pressure or high pressure ridge with weak surface winds typical environment especially for radiation fog. Surface dewpoint depression: Very small difference between the surface temperature and dewpoint indicates fog or mist at the surface.
Fog and stratus are boundary layer phenomena, and vertical cross sections should preferable be zoomed into the lowest or hPa or the atmosphere to see the features most conveniently. Isentropes: Potentially stable situation at the lowest part of the troposphere. Temperature: Surface for both fog types or elevated for advection Stratus temperature inversion.
Parameter Description Precipitation Shallow stratus radiation fog : generally no precipitation. Stratus with larger vertical extent especially advection fog : drizzle, in winter light snowfall or super cooled drizzle.
Reduced diurnal variation of temperature within cloudy areas. Wind incl. Other relevant information Visibility in Fog below m. Fluctuations in visibility, when cloud base temporarily lifted or lowered. Icing possible within the super cooled cloud conditions. The most probable location for icing near the cloud top, where droplet size is the largest.
Swedish Meteorological and Hydrological Institute. Journal of Remote Sensing, Vol. Weather and Forecasting, Vol. EYRE J. Monthly Weather Review, Vol.
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