Impacts of urbanization on long-term fog variation in Anhui Province, China

Shi, Chong; Roth, Matthias; Zhang, Hao; Li, Zihua

doi:10.1016/j.atmosenv.2008.08.002

Cited by 47 publications

(39 citation statements)

References 21 publications

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“…Klemm and Lin (2016) found that a change of ten percent in aerosol concentration had about the same effect on fog occurence as a change of 0.1°C in air temperature. Reduction in fog frequency over the last 30 years has been reported for more than 300 stations in Europe (Vautard et al 2009) and other localities (Gomez and Smith 1984;Koepke 1995, 1997;Kokkola et al 2003;Shi et al 2008;Witi and La Dochy 2008;van Oldenborgh et al 2010;Sugimoto et al 2013;Fu et al 2014). An increase in the frequency of fog events due to growing industrial activity and rising atmospheric pollution concentration is observed in India (Singh and Dey 2012;Shrivastava et al 2016) and other parts of South Asia (Syed et al 2012).…”

Section: Discussionmentioning

confidence: 99%

Synoptic climatology of fog in selected locations of southern Poland (1966–2015)

Łupikasza

Niedźwiedź

2016

Bulletin of Geography. Physical Geography Series

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Abstract. This paper investigates fog frequency in southern Poland in relation to various topography (concave and convex forms) and atmospheric circulation types. It also discusses long-term variability in the annual and seasonal number of days with fog. Daily information on fog occurrence was taken from three high quality synoptic stations representing various landforms: Kraków-Balice (bottom of the hollow), Katowice-Muchowiec (Silesian Upland) and Bielsko-Aleksandrowice (summit of Carpathian Foothill). In the central part of southern Poland during the last 50 years fog occurred on average during 53-67 days a year. The annual number of foggy days in Kraków (67 days) located in a structural basin was by 14-15 days higher than in Bielsko (53 days) situated in the Silesian Foothills. In the annual course, high fog occurrence (above 6 days per month) was observed from September to January, with the maximum in Kraków (10 days in October). At every station the monthly minimum of fog occurrence fell in July (2 days). In summer and spring the highest probability of fog occurrence was found on days with anticyclonic types and air advection from the northeastern (Na, NEa) and eastern (Ea, SEa) sectors. In autumn, a high probability was also found for the anticyclonic types with advection of air mass from the eastern and southern sectors. In the Carpathian Foothills (Bielsko) the probability of fog occurrence in winter was significantly enhanced only for the cyclonic types with air advection from the eastern sector (NEc, Ec, SEc) and nonadvective types Cc (cyclone centre) and Bc (cyclonic trough). Trends in the fog frequency were mostly insignificant. The only significant decreasing trend was found in Kraków on the annual scale and in summer when fog frequency was low.

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Section: Discussionmentioning

confidence: 99%

Synoptic climatology of fog in selected locations of southern Poland (1966–2015)

Łupikasza

Niedźwiedź

2016

Bulletin of Geography. Physical Geography Series

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“…In the case of cities located, for example, at the seaside or in the mountains, additional factors need to be included, e.g., atmospheric circulation (Witiw and LaDochy, 2008), ice cover of the sea waters (Gough and He, 2015) or cold air pool occurrence in the valleys (Scherrer and Appenzeller, 2014). The interactions among the factors mentioned are complex, and in particular circumstances, the importance of a given factor may change; for example, Shi et al (2008) showed that the impact of a city on fog formation depends on the stage of the city's development. Sachweh and Koepke (1995) suggested that the atmospheric effects which decrease fog, such as increasing temperature or moisture deficit, might outweigh those that promote fog, such as increasing aerosol concentration or decreasing winds.…”

Section: Introductionmentioning

confidence: 99%

“…Sachweh and Koepke (1995) summarized papers on fog and concluded that urban areas either decrease or increase (up to 100%) the fog frequency, depending on the city studied. The main factors which affect fog occurrence in urban areas are as follows: -urban heat island (UHI) magnitude (e.g., Koepke, 1995, 1997;LaDochy, 2005;Shi et al, 2008;Witiw and LaDochy, 2008;Li et al, 2012); -air humidity (e.g., Sachweh and Koepke, 1995;Shi et al, 2008;Li et al, 2012); -wind speed (e.g., Sachweh and Koepke, 1997); -aerosol concentrations (e.g., Appel et al, 1985;Oke, 1987;Sachweh and Koepke, 1995;LaDochy, 2005;Shi et al, 2008;Witiw and LaDochy, 2008;Li et al, 2012). In the case of cities located, for example, at the seaside or in the mountains, additional factors need to be included, e.g., atmospheric circulation (Witiw and LaDochy, 2008), ice cover of the sea waters (Gough and He, 2015) or cold air pool occurrence in the valleys (Scherrer and Appenzeller, 2014).…”

Section: Introductionmentioning

confidence: 99%

Impact of Natural and Anthropogenic Factors on Fog Frequency and Variability in Kraków, Poland in the Years 1966–2015

Bokwa

Wypych

Hajto

2018

Aerosol Air Qual. Res.

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The aim of the study was to determine the long term variability of fog occurrence in Kraków in the light of the changeability of fog favoring factors. The annual number of days with several fog characteristics was studied for the period 1966-2015, using data from two meteorological stations located in the city center and in the suburbs. For all these data series on fog, a strong decrease was observed in the study period, i.e., the number of days with fog decreased on average by about 60%, with the tendency being more distinct in the city center. Fog favoring conditions were determined by atmospheric circulation, wind speed, relative humidity, urban heat island (UHI) and air pollution and correlated with data on fog. Results statistically significant at p < 0.01 show that the relationship is the strongest between fog frequency and air pollution. However, as the air pollution levels decreased, especially after the change of political and economic system in 1989, environmental factors became decisive in controlling fog occurrence. Although the role of atmospheric circulation in fog formation is unquestionable, fog favoring circulation types (Sa, SWa, Ca, Ka) show no meaningful tendency and no significant correlation with long-term fog occurrence frequency. Therefore, decreasing trends in days with low wind speed and in days with relative humidity RH ≥ 80% and RH ≥ 95% are considered as additional factors which contributed to the observed fog frequency decrease. UHI showed no impact on fog frequency as in Kraków relief modified UHI (RMUHI) is observed and no significant changes in the part of UHI defined for the lowest part of the city were observed.

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“…The difference between air temperature at screen level in urban area and in surrounding rural area defines UHI magnitude or intensity (Oke, 1987). The interactions between fog and UHI are usually discussed in the context of the impact of increased air temperature in urbanized areas on potential conditions for fog formation (e.g., Koepke, 1995, 1997;LaDochy, 2005;Shi et al, 2008;Witiw and LaDochy, 2008;Li et al, 2012). The impact of fog on UHI, reported in most studies, is latent heat release during fog formation, which leads to an increase in minimum air temperature (e.g., Gough and He, 2015;Tam et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Role of Fog in Urban Heat Island Modification in Kraków, Poland

Bokwa

Wypych

Hajto

2018

Aerosol Air Qual. Res.

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The impact of fog on relief modified urban heat island (RMUHI) in Kraków has been presented using fog observations at 06 UTC from two meteorological stations: a rural one (Balice, B) and an urban one (Botanical Garden, BG) from the period 2006-2015. Daily UHI magnitude for the valley floor for the same period was estimated as T min BG-T min B, while for the period 2010-2015, eight daily courses of UHI were available, for the urban areas in the valley floor and 50 m above it, together with air temperature inversion data. UHI data for days with various combinations of fog occurrence and weather conditions were compared using non-parametric statistical tests: Wald-Wolfowitz test, Kolmogorov-Smirnov test and U Mann-Whitney test. Data of 2010-2015 were also the subject of cluster analysis (k-means method). Fog is an important factor decreasing UHI magnitude by about 1 K but mainly during weather conditions with little or no cloudiness and small wind speed or atmospheric calm, during anticyclonic synoptic situations, and only in the valley floor areas. With an increase in cloudiness and wind speed, the role of fog decreases and is similar in all parts of the city.

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Impacts of urbanization on long-term fog variation in Anhui Province, China

Cited by 47 publications

References 21 publications

Synoptic climatology of fog in selected locations of southern Poland (1966–2015)

Synoptic climatology of fog in selected locations of southern Poland (1966–2015)

Impact of Natural and Anthropogenic Factors on Fog Frequency and Variability in Kraków, Poland in the Years 1966–2015

Role of Fog in Urban Heat Island Modification in Kraków, Poland

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