UV solar irradiance from broadband radiation and other meteorological data

Paulescu, Marius; Stefu, Nicoleta; Paulescu, Eugenia; Calinoiu, Delia; Neculae, Adrian; Gravila, P. M.

doi:10.1016/j.atmosres.2009.12.007

Cited by 28 publications

(12 citation statements)

References 23 publications

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“…So it is difficult to determine the role of each variable under various sky conditions due to the combined effects of above factors, for example, being scattered by water droplets. The effects of cloudiness on UV irradiances can vary from small enhancements to almost total reduction (Paulescu et al , ). Therefore, it is essential to have as many observations as possible on a continuous basis to make a detailed study of the variation characteristics of UV radiation (Calbó et al , ).…”

Section: Introductionmentioning

confidence: 99%

Empirical studies of cloud effects on ultraviolet radiation inCentralChina

Wang

Gong

et al. 2013

Intl Journal of Climatology

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Global solar radiation (G) and ultraviolet radiation (UV) observed at Wuhan, China from 2006 to 2012 have been used to investigate the temporal variability of both radiant fluxes and the UV/G ratios (F UV ) at different time scales for the first time in central China. Clearness index (Kt) was used to study the cloud effects on F UV in each month under different sky conditions. It turned out that F UV reached higher values in summer and lower values in winter; F UV also increased generally with cloudiness. A UV model for cloud-free condition was developed by studying the dependence of hourly UV irradiations on the relative optical air mass (m), which has been assessed through the statistical indices: mean bias error (mbe), mean-absolute bias error (mabe) and root-mean-square error (rmse) whose values were 0.32, 7.3 and 8.64%, respectively. UV clearness index, m and Kt were further used for analysing the cloud effects, and different UV models under any sky conditions have been established and validated. Meanwhile, as a modulation for different sky conditions, both cloud modification factors were also used in the construction of a new type of UV model. Finally, by comparing the statistical indices from different models, the most suitable model was chosen for validating at Wuhan University (WHU) and two other sites in different regions of China under any atmospheric conditions, which suggested that the proposed model should be modified to account for local differences to produce better estimations in larger areas.

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Section: Introductionmentioning

confidence: 99%

Empirical studies of cloud effects on ultraviolet radiation inCentralChina

Wang

Gong

et al. 2013

Intl Journal of Climatology

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“…The effect of the clouds cannot be described accurately by the clearness index. Other properties of the clouds should be included in the relationship, as suggested by other works (see, e.g., [12,16,18,49,50,[53][54][55]). This is not an easy task as there is a large variability in cloud fields.…”

Section: Discussionmentioning

confidence: 99%

“…This may be explained by the fact that changes in some atmospheric constituents may affect I UV and not I, and accordingly that are not present in IŮ V , or reciprocally, that affect I and, hence, IŮ V and do not affect I UV . For example, Figure 4 in [49] exhibits examples of the dependence of the ratio of UV total (280-400 nm) to total irradiance as a function of water vapor column content or aerosol load. It has also been observed that the cloud effect on UV radiation is less than the cloud effect on total irradiance and may even be an enhancing effect [50].…”

Section: Deviations Between I Uv and Iů V For Formulae In Combinationmentioning

confidence: 99%

Assessment of Several Empirical Relationships for Deriving Daily Means of UV-A Irradiance from Meteosat-Based Estimates of the Total Irradiance

et al. 2016

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International audienceDaily estimates of the solar UV-A radiation (315–400 nm) at the surface, anywhere, anytime, are needed in many epidemiology studies. Satellite-derived databases of solar total irradiance, combined with empirical relationships converting totals into daily means of UV-A irradiance I UV , are a means to satisfy such needs. Four empirical relationships are applied to three different databases: HelioClim-3 (versions 4 and 5) and CAMS Radiation Service—formerly known as MACC-RAD—derived from Meteosat images. The results of these combinations are compared to ground-based measurements located in mid-latitude Europe, mostly in Belgium. Whatever the database, the relationships of Podstawczynska (2010) and of Bilbao et al. (2011) exhibit very large underestimation and RMSE on the order of 40%–50% of the mean I UV. Better and more acceptable results are attained with the relationships proposed by Zavodska and Reichrt (1985) and that of Wald (2012). The relative RMSE is still large and in the range 10%–30% of the mean I UV. The correlation coefficients are large for all relationships. Each of them captures most of the variability contained in the UV measurements and can be used in studies where correlation plays a major role

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“…Monthly average UV radiation increased from 0.19 MJ m À2 in December to 0.68 MJ m À2 in July (and August) with annual average value of 0.45 MJ m À2 . Correspondingly, the absolute maxima of the monthly G was [31,36,52]. These differences may due to the different climatic characteristics and local conditions [16].…”

Section: Methodology and Definitionsmentioning

confidence: 99%