Daily distribution of UV-Index in Belo Horizonte (Brazil) and the shadow rule

Silva, Abel A.

doi:10.1590/s0102-261x2009000300001

Cited by 8 publications

(7 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Thus, summertime and noon are not the only potential times for the occurrence of radiation enhancement events. These can be found throughout the diurnal period and year in the tropics, although they seem to be less frequent in seasons of lower cloudiness and higher SZA like the dry winter of Belo Horizonte (16,36).…”

Section: The Edr Measurementsmentioning

confidence: 99%

“…However, in contrast to other atmospheric contents, which only attenuate, clouds can also enhance the solar radiation reaching the Earth surface. Radiation enhancement events arise from augmentation in the diffuse component of global radiation (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). For the occurrence of such events, two main fundamental mechanisms exist, both based on the forward scattering of solar radiation from clouds (8,10,13,(19)(20)(21)(22)(23):…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Daily Maximum Erythemal Dose Rates in the Tropics

Silva¹,

Yamamoto

Correa

2018

Photochem & Photobiology

Self Cite

View full text Add to dashboard Cite

The maximum erythemal dose rate (EDRmax) at the Earth's surface tends to occur at local noon. However, clouds can make the timing of EDRmax significantly away from local noon. In fact, EDRmax and its time of occurrence depend mainly on the solar zenith angle at noon (SZAn), site's altitude, the total ozone column (TOC), cloud cover, cloud genera and aerosols. This work depicts the daily incidence of EDRmax for Belo Horizonte (19.92°S, 43.94°W, 858 m a.s.l.) in the Southern Hemisphere tropics for a period of five years (2005–2010). Daily values of EDRmax ranged from 0.063 W m−2 (1σ > 6.9%, Moderate UV‐Index of 3, winter) to 0.486 W m−2 (Extreme UVI of 19, summer). Indicative values of EDRmax for cloudless days were 0.336 W m−2 (summer, TOC = 258 Dobson Units), 0.311 W m−2 (fall, 260 DU), 0.253 W m−2 (spring, 274 DU) and 0.143 W m−2 (winter, 246 DU). Radiation enhancement events by clouds made EDRmax up to 45% higher than the reference EDRmax for cloudless summer skies at a time resolution of a few minutes. The main cloud genera to be associated with such events are Cumulus, Altocumulus, Altostratus and Stratocumulus. The EDR can also be significantly affected by aerosols, which attenuated on average 0.031 W m−2 (22%) of the erythemal UV in a case study at the site.

show abstract

Section: The Edr Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Daily Maximum Erythemal Dose Rates in the Tropics

Silva¹,

Yamamoto

Correa

2018

Photochem & Photobiology

Self Cite

View full text Add to dashboard Cite

show abstract

“…ED and EDR measurements have been carried out and analyzed by LLUV in BH . 50% (2000 J m −2 on average) of the daily ED is delivered within the noon time.…”

Section: Resultsmentioning

confidence: 99%

Improving Photoprotection Attitudes in the Tropics: Sunburn vs Vitamin D

Silva¹

2014

Photochem & Photobiology

Self Cite

View full text Add to dashboard Cite

The ultraviolet radiation of type B (the UVB) stimulates both the production of vitamin D (VD) and the incorporation of erythema dose (ED). The UVA also contributes to ED. The turning point between the benefit of producing VD and the harm of incorporating ED cannot be determined easily. However, the casual behavior regarding the exposure to the Sun can be changed in order to improve the protoprotection attitudes and create a trend towards benefit. In the case, people living in the low latitudes should exposure themselves to the Sun for a determined time interval within the noon time and avoid the Sun in other periods. This would produce an adequate amount of VD through the VD dose (207-214 J m(-2)) against minimum ED (≈105 J m(-2)) for skin type II. For it, unprotected forearms and hands must be exposed to the noon Sun (cloudless) for 11 min (winter) and 5 min (summer). The exposure at other times different from noon can represent increases of up to 24% in ED and up to 12 times in the time interval to be in the Sun in relation to the minimum amounts of both ED and time interval at noon.

show abstract

“…Um Biômetro Solar Light 501A (BSL, Solar Light Co., Inc., Glenside, USA) e um imageador Total Sky Imager 440A (TSI, Yankee Environmental Systems, Inc., Turners Falls, USA) foram instalados na torre do LLUV dentro do campus da Pontifícia Universidade Católica de Minas Gerais (PUC Minas) (Silva, 2009).…”

Section: Methodsunclassified

“…A intensidade de RUV na superfície terrestreé em função principalmente doângulo solar de zênite (ASZ), da coluna de ozônio, das nuvens, dos aerossóis e do albedo de superfície. Apesar da ameaça de mudanças globais devidoà ação antropogênica (McKenzie et al, 2007), o crescimento mundial do número de casos de câncer de pele se deve muito mais ao estilo de vida humano em relação ao Sol do que a qualquer mudança já identificada -a redução da camada de ozônio, por exemplo - (Godar, 2005;Silva, , 2009. Embasando essa tese estão algumas interpretações erradas da condição meteorológica diária como, por exemplo, a de que as nuvens sempre atenuam, e a níveis seguros, a incidência de RUV (WHO, 2002;Piacentini et al, 2003).…”

Section: Introductionunclassified

Taxa de dose eritematosa sob céu encoberto por alto-estrato: estudo de caso

Silva¹

2010

Rev. Bras. Geof.

Self Cite

View full text Add to dashboard Cite

ABSTRACT. The erythemal dose rate (EDR) on the Earth's surface depends mainly on the solar zenith angle, column ozone, clouds, aerosols and surface albedo.Clouds are the main atmospheric agent in the modulation of EDR. Therefore, an investigation into the effect of clouds on the ultraviolet radiation (UVR) incidence is an important matter due to the effects of UVR on the biosphere. In this work, a case study is reported where EDR incidences are presented for an overcast-sky scenario of Altostratus (As) in Belo Horizonte (BH, 19.92 • S, 43.94 • O, 858 m, 331 km 2 , Brazil). Although the attenuation yielded by the As layer, the incidence of UVR remained high setting in a threatening weather condition for people in outdoor activities.Keywords: solar ultraviolet radiation, clouds, cloud cover, UV-Index. RESUMO.A taxa de dose eritematosa (TDE) na superfície terrestre devidoà radiação ultravioleta (RUV) emitida pelo Sol depende principalmente doângulo solar de zênite, da coluna de ozônio, da cobertura de nuvens, dos aerossóis em suspensão e do albedo de superfície. As nuvens são o mais importante agente atmosférico na modulação da TDE, e uma investigação detalhada do efeito produzido por elas na incidência de RUV se justifica pelo impacto dessa radiação na biosfera. Neste trabalho, descreve-se um estudo de caso para a incidência de TDE sob céu completamente encoberto por alto-estrato (As) em Belo Horizonte (BH, 19,92 • S, 43,94 • O, 858 m, 331 km 2 , Brasil). Apesar da RUV ser atenuada pela camada de As, isso nãoé suficiente para reduzir a incidência da mesma em termos de TDE a níveis seguros, representando uma ameaçaàs pessoas em atividades ao ar livre.Palavras-chave: radiação solar ultravioleta, nuvens, cobertura de nuvens,Índice UV.Instituto de Estudos Avançados (IEAv), Rodovia dos Tamoios km 5,5, Putim, 12228-001 São José dos Campos, SP, Brasil.

show abstract

Daily distribution of UV-Index in Belo Horizonte (Brazil) and the shadow rule

Cited by 8 publications

References 26 publications

Daily Maximum Erythemal Dose Rates in the Tropics

Daily Maximum Erythemal Dose Rates in the Tropics

Improving Photoprotection Attitudes in the Tropics: Sunburn vs Vitamin D

Taxa de dose eritematosa sob céu encoberto por alto-estrato: estudo de caso

Contact Info

Product

Resources

About