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Nancy E. Westcott

1. Introduction Widespread dense fog can have large socioeconomic impacts through disruption of commerce and jeopardizing personal safety. Ground transportation can be severely affected. Low surface visibility can slow or delay ground transportation throughout the year and result in accidents. Data obtained from the Illinois Department of Transportation indicate that between 1975 and 1995 some 4000 collisions occurred annually under foggy conditions in Illinois, excluding the city of Chicago

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Robert Tardif and Roy M. Rasmussen

1. Introduction The present study further develops the characterization of fog events affecting the coastal urban region of New York, New York, in the northeastern United States presented by Tardif and Rasmussen (2007 , hereinafter TR07 ). In TR07 , a description of the overall character of fog was presented, focusing on the identification of the various fog types observed in a region centered on New York City (NYC; Fig. 1 ). Their study concluded that fog in this region is composed of

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Huijun Huang, Hongnian Liu, Jian Huang, Weikang Mao, and Xueyan Bi

1. Introduction Sea-fog forecasting under different synoptic and mesoscale conditions is crucial for commerce and travel, yet still a complicated problem worldwide. Most studies of sea fog focus on particular areas such as the U.S. West Coast and China’s Yellow Sea because sea-fog characteristics differ by area ( Koračin et al. 2014 ). For example, fog characteristics over the South China Sea are quite unique in many aspects including the formation, seasonal aspect, and extremely large fog

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H. J. S. Fernando, I. Gultepe, C. Dorman, E. Pardyjak, Q. Wang, S. W Hoch, D. Richter, E. Creegan, S. Gaberšek, T. Bullock, C. Hocut, R. Chang, D. Alappattu, R. Dimitrova, D. Flagg, A. Grachev, R. Krishnamurthy, D. K. Singh, I. Lozovatsky, B. Nagare, A. Sharma, S. Wagh, C. Wainwright, M. Wroblewski, R. Yamaguchi, S. Bardoel, R. S. Coppersmith, N. Chisholm, E. Gonzalez, N. Gunawardena, O. Hyde, T. Morrison, A. Olson, A. Perelet, W. Perrie, S. Wang, and B. Wauer

“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

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Binbin Zhou and Brad S. Ferrier

1. Introduction Surface visibility is crucial for aviation and land transportation safety. One of the reasons for a reduction in visibility is fogs—in particular, radiation fogs, which are a significant percentage of all fogs in the central region ( Westcott 2004 ), northeastern region ( Tardif 2004a ), and southern region of the United States ( Croft et al. 1997 ). The mechanism for radiation fog is very complex and has been extensively studied for over almost a century (e.g., Taylor 1917

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Ki-Young Heo and Kyung-Ja Ha

1. Introduction The formation and duration of sea fog are related to thermodynamical, dynamical and physical processes as well as the sea surface conditions. Because sea fog has a spatial structure on both the microscale, mesoscale, and time scale in hours, the formation and evolution of sea fog is modulated by variety of complicated dynamic and microphysical processes ( Gao et al. 2007 ). Gultepe et al. (2007) reported that a sea fog is a boundary layer phenomenon. Therefore

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I. Gultepe, M. Pagowski, and J. Reid

1. Introduction Fog formation is related to thermodynamical, dynamical, radiative, aerosol, and microphysical processes, as well as surface conditions. Within fog, the extinction of radiation at visible ranges results in low visibilities that can affect low-level flight conditions, marine traveling, shipping, and transportation. The high frequency of fog occurrence, experienced greater than 10% of the time in some regions of Canada ( Whiffen 2001 ), requires improvements in fog nowcasting and

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Otto Klemm, Thomas Wrzesinsky, Jörg Gerchau, and Frank Griessbaum

1. Introduction The collection of fog water has a long history ( Grunow 1955 ; Baumgartner 1958 ). The scientific scopes of such studies include cloud microphysical processes, fog water chemistry, the role of fog in the hydrology of watershed catchments, and the contribution of fog water fluxes to biogeochemical cycles in ecosystems. As with other atmospheric parameters such as temperature, wind, composition of air masses, and precipitation amount and chemistry, the long-term observation of

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Su-Ping Zhang, Shang-Ping Xie, Qin-Yu Liu, Yu-Qiang Yang, Xin-Gong Wang, and Zhao-Peng Ren

1. Introduction Sea fog often causes shipwrecks and disrupts transportation and other socioeconomic activities over the ocean and in coastal regions. The Yellow Sea experiences heavy fog over a significant fraction of the year. Figure 1 shows the number of fog days as a function of calendar month based on 30 yr of station observations. Stations on the northwest (NW) Yellow Sea coast typically record more than 50 foggy days a year while the maximum of over 80 days is found at Chengshantou (CST

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Dustin Fabbian, Richard de Dear, and Stephen Lellyett

valid for 24 h. These forecasts are used by the commercial airlines and Air Services Australia (formerly the Civil Aviation Safety Authority) for flight planning, in-flight decision making, and optimization of airport operations. BoM staff routinely review their forecasting performance to seek ongoing improvement, and this study is part of a coordinated effort between Macquarie University and the BoM in relation to the latter’s National Fog Project. 2. Fog and aviation The main use of TAFs by

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