Tropospheric Influence on Solar Ultraviolet Radiation: The Role of Clouds

Frederick, John E.; Snell, Hilary E.

doi:10.1175/1520-0442(1990)003<0373:tiosur>2.0.co;2

Cited by 76 publications

(32 citation statements)

References 8 publications

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“…UV irradiation is recognized as an effective inactivation method for culturable bioaerosols (Riley et al, 1976;Hwang et al, 2010). In addition, rain clouds are known to reduce the intensity of UV irradiation (Frederick and Snell, 1990;Calbó and González, 2005). Therefore, to test the hypothesis that the decrease of UV intensity on rainy days can explain the increase in bioaerosol concentrations, measurements of bioaerosol concentrations were conducted under strong UV irradiation and weak UV irradiation conditions in ambient air environments.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…It has been recognized that UV irradiation can inactivate culturable bioaerosols (Riley et al, 1976;Peccia et al, 2001;Lin and Li, 2002;Kujundzic et al, 2006;Hwang et al, 2010) and that rainclouds can decrease UV irradiation intensity (Frederick and Snell, 1990;Calbó and González, 2005). Therefore, to test the hypothesis that the decrease of UV intensity on rainy days can explain the increase in bioaerosol concentrations, we attempted to quantify ambient UV irradiation intensities and bioaerosol concentrations in Seoul to observe the relationship between these two parameters.…”

Section: Uv Effect Due To Rain (Bioaerosol Concentration With Varyingmentioning

confidence: 99%

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Why Does Rain Increase the Concentrations of Environmental Bioaerosols during Monsoon?

Kang

Heo

Lee

2015

Aerosol Air Qual. Res.

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Rain has been known to remove aerosol particles from the atmosphere; however, it was recently discovered that rain events during monsoon increase the concentrations of culturable bioaerosols in ground-level air environments. To explain this phenomenon, several hypotheses were tested via bioaerosol measurement experiments in this study. The experimental measurements with limited variations of environmental conditions revealed that the phenomenon of the effect of rain on bioaerosols might be caused by the transportation of bioaerosols by falling raindrops from higher altitude to the ground, where the bioaerosols accumulate, as well as by the decrease in UV irradiation intensity during rain events. We studied the effects of several environmental parameters on bioaerosol concentrations.

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Section: Experimental Methodsmentioning

confidence: 99%

Section: Uv Effect Due To Rain (Bioaerosol Concentration With Varyingmentioning

confidence: 99%

Why Does Rain Increase the Concentrations of Environmental Bioaerosols during Monsoon?

Kang

Heo

Lee

2015

Aerosol Air Qual. Res.

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“…10 Cloud cover has been found to be the second most effective shield (after stratospheric ozone) to limit the amount of solar UVR that reaches the earth's surface. 15 Cloud cover can either attenuate or enhance the amount of solar UVR reaching the ground. 10 Whether attenuation or enhancement occurs is determined by factors such as cloud location (which refers to cloud height and whether or not the cloud is covering the solar disc), percentage cover, optical thickness and liquid water content.…”

Section: Introductionmentioning

confidence: 99%

Real-time measurement of outdoor worker’s exposure to solar ultraviolet radiation in Pretoria, South Africa

Makgabutlane¹,

Wright²

2015

S. Afr. J. Sci.

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The city of Pretoria in South Africa receives considerable solar ultraviolet radiation (UVR) because of its low latitude (22–35°S) and relatively clear skies. Certain meteorological factors affect the amount of solar UVR that reaches the ground; the most dominant factors being stratospheric ozone, cloud cover and solar zenith angle. It is known that overexposure to solar UVR may lead to the development of adverse health conditions, the most significant being skin cancer. Outdoor workers spend a significant amount of time outside and are thus susceptible to this risk. In this case study, we estimated, for the first time, the realtime solar UVR exposure of an outdoor worker in Pretoria. Measurements were made on 27 and 28 May 2013 using a handheld ultraviolet index (UVI) meter calibrated against a science-grade biometer at the South African Weather Service in Pretoria. Personal exposure estimation was used to discern the pattern in diurnal and annual sunburn risk for the outdoor worker. Ambient UVR levels ranged from 0 UVI to 4.66 UVI and the outdoor worker’s potential exposure estimates regularly exceeded 80% of these levels depending on the time of day. The risk of sunburn was evident; however, actual incidents would depend on individual skin photosensitivity and melanin content, as well as sun protection used. Further research is needed to determine the personal exposure estimations of outdoor workers in other provinces in which solar UVR levels may be equally high, or higher than those in Pretoria.

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“…For this, the information routinely registered in most meteorological stations is used: cloud type and amount, expressed in terms of fractional cloud coverage in oktas, which are usually recorded in a 3-hourly database. This kind of approach has been followed in previous studies (Ilyas, 1987;Frederick and Snell, 1990;Frederick et al, 1993;Blumthaler et al, 1994Blumthaler et al, , 1996Thiel et al, 1997;Kuchinke and Núñez, 1999;Grant and Heisler, 2000;Josefsson and Landelius, 2000;Alados-Arboledas et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Influence of cloudiness over the values of erythemal radiation in Valencia, Spain

Esteve

Marı́n

Tena

et al. 2009

Intl Journal of Climatology

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The influence of cloudiness over experimental UV erythemal radiation (UVER) has been studied. This influence has been analysed considering total cloudiness and low clouds. The measurements of cloudiness correspond to the daily values registered at 13 : 00 GMT at the Meteorological Centre of Valencia, which is part of the State Agency of Meteorology of Spain (AEMET). The UVER measurements were made using a YES UVB-1 radiometer located on the roof terrace of the Physics Faculty at the Burjassot Campus, Valencia (latitude 39.508°, longitude −0.418°, 60 m above sea level). First, a statistical analysis of cloudiness at 13 : 00 GMT in Valencia was carried out, confirming that the situation is mainly clear skies or very few clouds. Next, the influence of cloudiness on experimental UVER values was analysed, for both total cloudiness and low clouds. The experimental UVER values decrease as cloudiness increases for all solar zenith angles (SZA), and this reduction increases with the zenith angle. Next, the cloud modification factor (CMF) has been defined to reduce the influence of the zenith angle and ozone over the UVER. In order to quantify the relationship between CMF and the degree of cloudiness in oktas, linear, quadratic and potential regressions for both total cloudiness and low clouds have been calculated. Transmissivity due to total cloudiness and for overcast skies reaches 40%. On the other hand, the analysis of the influence over the zenith angle shows that CMF reduces as the zenith angle increases in the case of both total cloudiness and low clouds. With regard to the low cloud CMF, the results are comparable to those proposed by the COST-713 Action "UV-B Forecasting" for partially cloudy or cloudy skies (70% and 50%, respectively). Finally, the relationship between the CMF and the clearness index (k T ) has been analysed, as both parameters are simple indicators of cloudiness. It has been proved that such relationship is close to unity for zenith angles in the mid-range, while the CMF is greater than k T for lower SZA and is less than k T for high SZA, which indicates a certain dependence of these two parameters on the zenith angle.

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Tropospheric Influence on Solar Ultraviolet Radiation: The Role of Clouds

Cited by 76 publications

References 8 publications

Why Does Rain Increase the Concentrations of Environmental Bioaerosols during Monsoon?

Why Does Rain Increase the Concentrations of Environmental Bioaerosols during Monsoon?

Real-time measurement of outdoor worker’s exposure to solar ultraviolet radiation in Pretoria, South Africa

Influence of cloudiness over the values of erythemal radiation in Valencia, Spain

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