Aureolegraph internal scattering correction

DeVore, John; Villanucci, D. P.; LePage, Andrew J.

doi:10.1364/ao.51.007891

Cited by 3 publications

(1 citation statement)

References 15 publications

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“…For the SAM 400 series, as the one in Masdar City, measurements from the aureole camera for ξ < 0.52 are discarded (Wilbert, 2014). The internal scattering correction of DeVore et al (2012b) was not applied to the downloaded SAM data.…”

Section: Sam Datamentioning

confidence: 99%

Can AERONET data be used to accurately model the monochromatic beam and circumsolar irradiances under cloud-free conditions in desert environment?

et al. 2015

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Abstract. Routine measurements of the beam irradiance at normal incidence include the irradiance originating from within the extent of the solar disc only (DNI S ), whose angular extent is 0.266 • ± 1.7 %, and from a larger circumsolar region, called the circumsolar normal irradiance (CSNI). This study investigates whether the spectral aerosol optical properties of the AERONET stations are sufficient for an accurate modelling of the monochromatic DNI S and CSNI under cloud-free conditions in a desert environment. The data from an AERONET station in Abu Dhabi, United Arab Emirates, and the collocated Sun and Aureole Measurement instrument which offers reference measurements of the monochromatic profile of solar radiance were exploited. Using the AERONET data both the radiative transfer models libRadtran and SMARTS offer an accurate estimate of the monochromatic DNI S , with a relative root mean square error (RMSE) of 6 % and a coefficient of determination greater than 0.96. The observed relative bias obtained with libRadtran is +2 %, while that obtained with SMARTS is −1 %. After testing two configurations in SMARTS and three in libRadtran for modelling the monochromatic CSNI, libRadtran exhibits the most accurate results when the AERONET aerosol phase function is presented as a two-term HenyeyGreenstein phase function. In this case libRadtran exhibited a relative RMSE and a bias of respectively 27 and −24 % and a coefficient of determination of 0.882. Therefore, AERONET data may very well be used to model the monochromatic DNI S and the monochromatic CSNI. The results are promising and pave the way towards reporting the contribution of the broadband circumsolar irradiance to standard measurements of the beam irradiance.

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Section: Sam Datamentioning

confidence: 99%

Can AERONET data be used to accurately model the monochromatic beam and circumsolar irradiances under cloud-free conditions in desert environment?

et al. 2015

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Measurement of Solar Radiance Profiles With the Sun and Aureole Measurement System

Wilbert¹,

Reinhardt²,

DeVore

et al. 2013

Journal of Solar Energy Engineering

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Due to forward scattering of direct sunlight in the atmosphere, the circumsolar region closely surrounding the solar disk looks very bright. The radiation coming from this region, the circumsolar radiation, is in large part included in common direct normal irradiance (DNI) measurements, but only partially intercepted by the receivers of focusing collectors. This effect has to be considered in the performance analysis of concentrating collectors in order to avoid overestimation of the intercepted irradiance. At times, the overestimation reaches more than 10% for highly concentrating systems even for sky conditions with relevant DNI above 200 W/m2. The amount of circumsolar radiation varies strongly with time, location and sky conditions. However, no representative sunshape measurements exist for locations that are now of particular interest for concentrating solar power (CSP) or concentrating photovoltaics (CPV). A new sunshape measurement system is developed and analyzed in this study. The system consists of the sun and aureole measurement instrument (SAM), an AERONET sun photometer and postprocessing software. A measurement network is being created with the presented system. The uncertainty of this system is significantly lower than what was obtained with previous devices. In addition, the spectral optical properties of circumsolar radiation are determined. As a result, the necessary information for CSP and CPV systems, and a basis for the development of modeling methods for circumsolar radiation, can now be achieved.

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Can AERONET data be used to accurately model the monochromatic beam and circumsolar irradiances under cloud-free conditions in desert environment?

Eissa¹,

Blanc²,

Wald³

et al. 2015

Preprint

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Abstract. Routine measurements of the beam irradiance at normal incidence (DNI) include the irradiance originating from within the extent of the solar disc only (DNIS) whose angular extent is 0.266° ± 1.7 %, and that from a larger circumsolar region, called the circumsolar normal irradiance (CSNI). This study investigates if the spectral aerosol optical properties of the AERONET stations are sufficient for an accurate modelling of the monochromatic DNIS and CSNI under cloud-free conditions in a desert environment. The data from an AERONET station in Abu Dhabi, United Arab Emirates, and a collocated Sun and Aureole Measurement (SAM) instrument which offers reference measurements of the monochromatic profile of solar radiance, were exploited. Using the AERONET data both the radiative transfer models libRadtran and SMARTS offer an accurate estimate of the monochromatic DNIS, with a relative root mean square error (RMSE) of 5 %, a relative bias of +1 % and acoefficient of determination greater than 0.97. After testing two configurations in SMARTS and three in libRadtran for modelling the monochromatic CSNI, libRadtran exhibits the most accurate results when the AERONET aerosol phase function is presented as a Two Term Henyey–Greenstein phase function. In this case libRadtran exhibited a relative RMSE and a bias of respectively 22 and −19 % and a coefficient of determination of 0.89. The results are promising and pave the way towards reporting the contribution of the broadband circumsolar irradiance to standard DNI measurements.

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Aureolegraph internal scattering correction

Cited by 3 publications

References 15 publications

Can AERONET data be used to accurately model the monochromatic beam and circumsolar irradiances under cloud-free conditions in desert environment?

Can AERONET data be used to accurately model the monochromatic beam and circumsolar irradiances under cloud-free conditions in desert environment?

Measurement of Solar Radiance Profiles With the Sun and Aureole Measurement System

Can AERONET data be used to accurately model the monochromatic beam and circumsolar irradiances under cloud-free conditions in desert environment?

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