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“There it is, fog, atmospheric moisture still uncertain in destination, not quite weather and not altogether mood, yet partaking of both.” —Hal Borland Fog is a collection of suspended water droplets or ice crystals near the Earth’s surface that causes horizontal near-surface visibility to drop below 1 km ( Myers 1968 ; WMO 1992 ). Different from clouds, fog forms near the surface and hence dynamic, microphysical, physicochemical, thermodynamic, surface, and environmental processes that
“There it is, fog, atmospheric moisture still uncertain in destination, not quite weather and not altogether mood, yet partaking of both.” —Hal Borland Fog is a collection of suspended water droplets or ice crystals near the Earth’s surface that causes horizontal near-surface visibility to drop below 1 km ( Myers 1968 ; WMO 1992 ). Different from clouds, fog forms near the surface and hence dynamic, microphysical, physicochemical, thermodynamic, surface, and environmental processes that
Increased understanding of ice fog microphysics can improve frost and ice fog prediction using forecast models and remote-sensing retrievals, thereby reducing potential hazards to aviation. Ice fog occurs usually at temperatures less than −15°C because of direct deposition of water vapor into ice nuclei. It significantly affects aviation and transportation in northern latitudes because ice fog causes low visibilities and ice crystal accumulation on the surface of structures. Ice fog may also be
Increased understanding of ice fog microphysics can improve frost and ice fog prediction using forecast models and remote-sensing retrievals, thereby reducing potential hazards to aviation. Ice fog occurs usually at temperatures less than −15°C because of direct deposition of water vapor into ice nuclei. It significantly affects aviation and transportation in northern latitudes because ice fog causes low visibilities and ice crystal accumulation on the surface of structures. Ice fog may also be
Fog life cycles in the central Namib Desert have been studied during the NaFoLiCA intensive observation period, which is described together with initial analyses of the extensive dataset. Fog as a meteorological phenomenon is associated with low visibility, high relative humidity/cold air, and danger for car/air traffic. However, in one of the driest regions on Earth—the Namib Desert—fog instead represents a major source of water for plants and animals. Figure 1 illustrates this striking
Fog life cycles in the central Namib Desert have been studied during the NaFoLiCA intensive observation period, which is described together with initial analyses of the extensive dataset. Fog as a meteorological phenomenon is associated with low visibility, high relative humidity/cold air, and danger for car/air traffic. However, in one of the driest regions on Earth—the Namib Desert—fog instead represents a major source of water for plants and animals. Figure 1 illustrates this striking
The potential of cellular network infrastructure as a futuristic system for monitoring fog is introduced. The Glossary of Meteorology ( Glickman 2000 ) defines fog as water droplets suspended in the atmosphere near Earth’s surface that reduce visibility to less than 1 km. The intensity of fog can be characterized by its liquid water content (LWC) and its droplet number concentration N D or by the visibility existing in the area observed during the occurrence of the phenomenon. According to
The potential of cellular network infrastructure as a futuristic system for monitoring fog is introduced. The Glossary of Meteorology ( Glickman 2000 ) defines fog as water droplets suspended in the atmosphere near Earth’s surface that reduce visibility to less than 1 km. The intensity of fog can be characterized by its liquid water content (LWC) and its droplet number concentration N D or by the visibility existing in the area observed during the occurrence of the phenomenon. According to
The Cloud Physics Section of the Atmospheric Sciences Research Center-State University of New York at Albany conducted a cooperative field study (FOG-82) during the autumn of 1982 as part of an ongoing radiation-fog research program. A computer-controlled data-acquisition system consisting of sophisticated soil, surface, and boundary-layer sensors, as well as contemporary aerosol and droplet probes was developed. These data are being used to address a variety of critical problems related to radiation-fog evolution.
Scientists from 10 universities and research laboratories participated in portions of FOG-82. Research objectives included studies of fog mesoscale meteorology, radiation studies, low-level water budget, vertical fog structure, fog supersaturation, condensation nuclei, and fog-water chemistry, as well as radiation-fog life cycles. A comprehensive description of the FOG-82 program and objectives is presented.
The Cloud Physics Section of the Atmospheric Sciences Research Center-State University of New York at Albany conducted a cooperative field study (FOG-82) during the autumn of 1982 as part of an ongoing radiation-fog research program. A computer-controlled data-acquisition system consisting of sophisticated soil, surface, and boundary-layer sensors, as well as contemporary aerosol and droplet probes was developed. These data are being used to address a variety of critical problems related to radiation-fog evolution.
Scientists from 10 universities and research laboratories participated in portions of FOG-82. Research objectives included studies of fog mesoscale meteorology, radiation studies, low-level water budget, vertical fog structure, fog supersaturation, condensation nuclei, and fog-water chemistry, as well as radiation-fog life cycles. A comprehensive description of the FOG-82 program and objectives is presented.
A collaborative field and modeling study used a small system of valleys as a natural laboratory to study the formation and evolution of fog. Atmospheric fog can have a high impact on human activity, particularly transport ( Gultepe et al. 2007 ). Delays due to poor visibility can be extensive and costly. Agarwal et al. (2005) estimated that fog causes a decrease in vehicle speed of 6%–12% and a reduction in traffic capacity of 10%–12% on freeways in Iowa. Figures for the impact of fog on
A collaborative field and modeling study used a small system of valleys as a natural laboratory to study the formation and evolution of fog. Atmospheric fog can have a high impact on human activity, particularly transport ( Gultepe et al. 2007 ). Delays due to poor visibility can be extensive and costly. Agarwal et al. (2005) estimated that fog causes a decrease in vehicle speed of 6%–12% and a reduction in traffic capacity of 10%–12% on freeways in Iowa. Figures for the impact of fog on
Visibilities of 100 to 200 miles over large areas are reported by pilots flying in the Arctic winter of interior Alaska. However, when the airport is reached, they find ice fog and visibility near zero. This condition is described and reasons are presented for ice fog formation and persistence in the vicinity of towns while other areas equally cold remain fog free.
Visibilities of 100 to 200 miles over large areas are reported by pilots flying in the Arctic winter of interior Alaska. However, when the airport is reached, they find ice fog and visibility near zero. This condition is described and reasons are presented for ice fog formation and persistence in the vicinity of towns while other areas equally cold remain fog free.
Studies carried out in Alaska and Canada have shown that fog is a relatively rare phenomenon at temperatures between 0° and − 30°F, with a minimum frequency between − 20° and −30°. At still lower temperatures, however, the frequency of fog increases rapidly. This effect is noted only in the immediate vicinity of inhabited areas, such as towns and airfields. The reason for the sudden increase in fog frequency at these temperatures, and the rarity or lack of fog at the higher temperatures, has not been heretofore explained. In a recent study on aircraft condensation trails, it was shown that if the temperature is sufficiently low (between − 20 and − 40°F, depending on the relative humidity), the burning of hydrocarbon fuels, such as would occur in towns and at airfields, easily results in supersaturation of the air and a “surface contrail” or ice fog. At higher temperatures, on the other hand, combustion actually reduces the relative humidity of the atmosphere, hindering the formation of fog. In this paper it is shown that low-temperature (ice) fogs form as a result of the combustion process, and curves are presented showing the temperature-dew-point relationship necessary for the formation of such fogs.
Studies carried out in Alaska and Canada have shown that fog is a relatively rare phenomenon at temperatures between 0° and − 30°F, with a minimum frequency between − 20° and −30°. At still lower temperatures, however, the frequency of fog increases rapidly. This effect is noted only in the immediate vicinity of inhabited areas, such as towns and airfields. The reason for the sudden increase in fog frequency at these temperatures, and the rarity or lack of fog at the higher temperatures, has not been heretofore explained. In a recent study on aircraft condensation trails, it was shown that if the temperature is sufficiently low (between − 20 and − 40°F, depending on the relative humidity), the burning of hydrocarbon fuels, such as would occur in towns and at airfields, easily results in supersaturation of the air and a “surface contrail” or ice fog. At higher temperatures, on the other hand, combustion actually reduces the relative humidity of the atmosphere, hindering the formation of fog. In this paper it is shown that low-temperature (ice) fogs form as a result of the combustion process, and curves are presented showing the temperature-dew-point relationship necessary for the formation of such fogs.
