The erythemal clearness index for Valencia, Spain

Abstract

ABSTRACT:The values of three clearness indices have been measured for the city of Valencia: k t , the clearness index for the whole solar spectrum, k tUV the clearness index for the ultraviolet range, and the erythemal clearness index for the erythemal radiation k tUVER , corresponding to the solar radiation weighted by the erythemal action spectrum on human skin, normalized with respect to the solar constant corresponding to that spectrum. The measurements of k tUV reached values that were approximately 54% of that corresponding to k t , while those of k tUVER were much smaller. Some statistics of the erythemal clearness index have been calculated both for monthly as well as hourly means. The shape of the distribution in both cases was nearly normal, so standard deviation and variance were used to analyse the dispersion of the data. The ratio of the erythemal clearness index and the corresponding solar irradiance was also studied. When only the central hours of the day were considered the relation between the two was markedly linear, giving a correlation coefficient that reached 99%.

Ultraviolet exposure for different outdoor sports in Valencia, Spain

“…For a constant ozone value of 300 dobson units (DU), the error given by the calibration matrix remained below 9% for zenith angles below 70°. Additional calibration of this radiometer was carried out by the Earth Physics Department of the UPV by comparison with an Optronic OL-754 spectroradiometer (Optronic Laboratories, Inc., Orlando, FL, USA) equipped with a double monochromator with a spectral range that extends from 250 nm to 800 nm.The values given by the latter equipment were convolved with the erythemal action spectrum and then integrated and compared with the values obtained with the UVB-1 (30,31).…”

Solar UV exposure in construction workers in Valencia, Spain

“…Additional calibration of this radiometer was carried out by the Earth Physics Department of the UV by comparison with an Optronic OL-754 spectroradiometer equipped with a double monochromator with a spectral range that extends from 250 nm to 800 nm. The values given by the Optronic spectroradiometer were convolved with the erythemal action spectrum and then integrated and compared with the values obtained from the UVB-1 (Cañada et al, 2008;Tena et al, 2009). …”

Diffuse Ultraviolet Erythemal Irradiance on Inclined Planes: A Comparison of Experimental and Modeled Data

“…The fact that the models underestimate the diffuse irradiance on the south‐facing plane can be explained because all of them are based on the Isotropic model, which underestimates the radiation in the presence of visible sun. The anisotropic models are based on corrections of the Isotropic, and they depend on the clearness index or modified coefficients of this parameter and its value is very low for the UVER range (24). In the south‐facing plane almost all the models give similar results (between 13% and 14% for the RMSD).…”

“…In order to use a general criterion, easy to reproduce to other similar radiometers, 70° was taken as a cutoff point, thus ensuring an error of less than 10% in the experimental values. Therefore, in the following calculations values over zenith angles of 70° have been eliminated both for the horizontal plane as for the inclined planes as we did in previous studies (24,25).…”