Evolution of erythemal and total shortwave solar radiation in Valladolid, Spain: Effects of atmospheric factors

Miguel, A. de; Román, Roberto; Bilbao, J.; Mateos, David

doi:10.1016/j.jastp.2010.11.021

Cited by 51 publications

(27 citation statements)

References 35 publications

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“…Clouds produce the strongest changes in solar radiation with a substantial decrease of the direct component and an increase of the diffuse radiation, which lead to a decrease in global radiation (Alados et al, 2000;Alados-Arboledas et al, 2003;de Miguel et al, 2011b). The influence of the cloudiness on solar radiation has a significant spectral dependence, being weaker when the wavelength is shorter (Foyo-Moreno et al, 2001;Bilbao et al, 2011;de Miguel et al, 2011a).…”

Section: R Román Et Al: Calibration Of An All-sky Cameramentioning

confidence: 99%

Calibration of an all-sky camera for obtaining sky radiance at three wavelengths

et al. 2012

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Abstract. This paper proposes a method to obtain spectral sky radiances, at three wavelengths (464, 534 and 626 nm), from hemispherical sky images. Images are registered with the All-Sky Imager installed at the Andalusian Center for Environmental Research (CEAMA) in Granada (Spain). The methodology followed in this work for the absolute calibration in radiance of this instrument is based on the comparison of its output measurements with modelled sky radiances derived from the LibRadtran/UVSPEC radiative transfer code under cloud-free conditions. Previously, in order to check the goodness of the simulated radiances, these are compared with experimental values recorded by a CIMEL sunphotometer. In general, modelled radiances are in agreement with experimental data, showing mean differences lower than 20 % except for the pixels located next to the Sun position that show larger errors.The relationship between the output signal of the All-Sky Imager and the modelled sky radiances provides a calibration matrix for each image. The variability of the matrix coefficients is analyzed, showing no significant changes along a period of 5 months. Therefore, a unique calibration matrix per channel is obtained for all selected images (a total of 705 images per channel). Camera radiances are compared with CIMEL radiances, finding mean absolute differences between 2 % and 15 % except for pixels near to the Sun and high scattering angles. We apply these calibration matrices to three images in order to study the sky radiance distributions for three different sky conditions: cloudless, overcast and partially cloudy. Horizon brightening under cloudless conditions has been observed together with the enhancement effect of individual clouds on sky radiance.

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Section: R Román Et Al: Calibration Of An All-sky Cameramentioning

confidence: 99%

Calibration of an all-sky camera for obtaining sky radiance at three wavelengths

et al. 2012

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“…Previous studies have indicated that the atmospheric compounds with the strongest influence on UVB radiation are ozone, aerosols, and clouds Antón et al, 2012). Moreover, other gasses such as water vapor control irradiance in the solar infrared bands reaching the Earth's surface (Marín et al, 2007;Jacovides et al, 2009;Bilbao et al, 2011;de Miguel et al, 2011). In previous papers (Adam, 2010(Adam, , 2014, the effects of ozone, water vapor, and aerosols on hourly UVB and G were examined in detail at Qena, as well as the effect of SZA.…”

Section: Resultsmentioning

confidence: 99%

Comparative analysis of cloud effects on ultraviolet-B and broadband solar radiation: Dependence on cloud amount and solar zenith angle

Adam

Ahmed

2016

Atmospheric Research

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“…In this study, we corroborated the non-linear relationship between CRF SW and S CV , that, is a result of the non-linear function linking solar irradiance and fractional cloud cover. As we know, the cloud influence on solar radiation varies throughout the solar spectrum (e.g., Alados-Arboledas et al, 2003;de Miguel et al, 2011). We carried out this analysis at two different SZAs and, as mentioned before, the CRF SW values were smaller for the larger SZA.…”

Section: Role Of the Cloud Cover On Crf Swmentioning

confidence: 95%

“…This empirical model was already used for the estimation of SW radiation in other studies (e.g., Mateos et al, 2010;de Miguel et al, 2011). Table 1 shows the three fitting coefficients (c 1 , c 2 and c 3 ) for each interval of AOD 440 nm that were obtained for this database.…”

Section: Empirical Sw Model Under Cloud-free Conditionsmentioning

confidence: 99%

Short-wave radiative forcing at the surface for cloudy systems at a midlatitude site

Mateos¹,

Antón

Cazorla³

et al. 2013

Tellus B: Chemical and Physical Meteorology

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Six-year data (2006–2011) of short-wave (SW) radiation, aerosol optical depth and cloud fraction were used in the evaluation of cloud radiative forcing (1-min data) at the surface in the SW spectral range at Granada station (South-Western Europe). Three different systems were analysed in this study: cloud radiative forcing (CRFSW), cloud–aerosol radiative forcing (CARFSW) and aerosol radiative forcing under cloudy conditions (ARFSW). Average values of these variables presented a clear dependence on solar zenith angle (SZA), for example, at SZA=30°, the results were CRFSW=−78 W m−2, CARFSW=−100 W m−2 and ARFSW=−22 W m−2, and the values decreased to CRFSW=−50 W m−2, CARFSW=−69 W m−2 and ARFSW=−19 W m−2 at SZA=60°. These three variables exhibited a similar pattern: they increased in the absolute magnitude up to moderate SZAs and strongly decreased towards zero for high SZAs. The hemispherical fractional sky cover (SCV) and the fractional sky cover inside the octant where the Sun is placed (SCV-Sun) also played a key role in the determination of cloud forcing. As expected, the strongest cloud effect appeared when clouds covered the Sun. However, when SCV-Sun was low or moderate and total SCV was over 0.5, there was a high likelihood of enhancement occurrence (i.e., positive cloud forcing values). Finally, the evolution of CRFSW values during a case study (ranging from −600 to +200 W m−2) with a wide variety of cloud conditions could be explained by the temporal evolution of SCV and SCV-Sun

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Evolution of erythemal and total shortwave solar radiation in Valladolid, Spain: Effects of atmospheric factors

Cited by 51 publications

References 35 publications

Calibration of an all-sky camera for obtaining sky radiance at three wavelengths

Calibration of an all-sky camera for obtaining sky radiance at three wavelengths

Comparative analysis of cloud effects on ultraviolet-B and broadband solar radiation: Dependence on cloud amount and solar zenith angle

Short-wave radiative forcing at the surface for cloudy systems at a midlatitude site

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