How close to detailed spectral calculations is the k-distribution method and correlated-k approximation of Kato et al. (1999) in each spectral interval?

Nyamsi, William Wandji; Espinar, Bella; Blanc, Philippe; Wald, Lucien

doi:10.1127/metz/2014/0607

Cited by 15 publications

(14 citation statements)

References 8 publications

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“…The correlation coefficient is greater than 0.99. It is also shown that the proposed technique provides better results than two state-of-the-art empirical methods estimating the global PPFD from the global irradiance (Jacovides et al, 2004;Udo and Aro, 1999).…”

Section: Discussionmentioning

confidence: 99%

“…The PAR spectral band [400, 700] nm is covered by 11 KB, from #6 [363,408] nm to #16 [684,704] nm (Table 1). Wandji Nyamsi et al (2014) demonstrated that as a whole the approach of Kato et al (1999) offer accurate estimates of the spectral irradiance in most of the 32 KB when compared to detailed spectral calculations in clear sky and cloudy conditions, and especially for the KB #6 to 16. It follows that the PAR may be computed by a Riemann sum based on 11 KB instead of 300 NBs.…”

Section: Problem Statementmentioning

confidence: 99%

“…Then, these performances are compared to those obtained for Q P by the methods proposed by Jacovides et al (2004), Udo and Aro (1999) and the weighted sum (Eq. 9).…”

Section: Numerical Validationmentioning

confidence: 99%

“…These figures prove the good level of performance of the proposed technique. Figure 2 exhibits the statistical indicators for Q P obtained by the methods of Jacovides et al (2004), Udo and Aro (1999), weighted sum and the proposed technique. The method of Jacovides et al underestimates the PAR by −7.4 %; the relative RMSE is 9.6 %.…”

Section: Performance Of the Proposed Techniquementioning

confidence: 99%

“…This scarcity leads researchers and practitioners to calculate PAR from the global broadband solar irradiance by empirical means. For example, Udo and Aro (1999) proposed a ratio of 2.079 between the daily mean of G and the daily mean of Q P :…”

Section: Introductionmentioning

confidence: 99%

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Estimating the photosynthetically active radiation under clear skies by means of a new approach

et al. 2015

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Abstract. The k-distribution method and the correlated-k approximation of Kato et al. (1999) is a computationally efficient approach originally designed for calculations of the broadband solar radiation by dividing the solar spectrum in 32 specific spectral bands from 240 to 4606 nm. This paper describes a technique for an accurate assessment of the photosynthetically active radiation (PAR) from 400 to 700 nm at ground level, under clear-sky conditions using twelve of these spectral bands. It is validated against detailed spectral calculations of the PAR made by the radiative transfer model libRadtran. For the direct and global PAR irradiance, the bias is −0.4 W m −2 (−0.2 %) and −4 W m −2 (−1.3 %) and the root mean square error is 1.8 W m −2 (0.7 %) and 4.5 W m −2 (1.5 %). For the direct and global Photosynthetic Photon Flux Density, the biases are of about +10.3 µmol m −2 s −1 (+0.8 %) and 1.9 µmol m −2 s −1 (−0.1 %) respectively, and the root mean square error is 11.4 µmol m −2 s −1 (0.9 %) and 4.0 µmol m −2 s −1 (0.3 %). The correlation coefficient is greater than 0.99. This technique provides much better results than two state-of-the-art empirical methods computing the daily mean of PAR from the daily mean of broadband irradiance.

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Section: Discussionmentioning

confidence: 99%

Section: Problem Statementmentioning

confidence: 99%

“…Then, these performances are compared to those obtained for Q P by the methods proposed by Jacovides et al (2004), Udo and Aro (1999) and the weighted sum (Eq. 9).…”

Section: Numerical Validationmentioning

confidence: 99%

Section: Performance Of the Proposed Techniquementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Estimating the photosynthetically active radiation under clear skies by means of a new approach

et al. 2015

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Detecting clear‐sky periods from photovoltaic power measurements

Wandji Nyamsi,

Lindfors

2024

Meteorological Applications

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A method for detecting clear‐sky periods from photovoltaic (PV) power measurements is presented and validated. It uses five tests dealing with parameters characterizing the connections between the measured PV power and the corresponding clear‐sky power. To estimate clear‐sky PV power, a PV model has been designed using as inputs downwelling shortwave irradiance and its direct and diffuse components received at ground level under clear‐sky conditions as well as reflectivity of the Earth's surface and extraterrestrial irradiance, altogether provided by the McClear service. In addition to McClear products, the PV model requires wind speed and temperature as inputs taken from ECMWF twentieth century reanalysis ERA5 products. The performance of the proposed method has been assessed and validated by visual inspection and compared to two well‐known algorithms identifying clear‐sky periods with broadband global and diffuse irradiance measurements on a horizontal surface. The assessment was carried out at two stations located in Finland offering collocated 1‐min PV power and broadband irradiance measurements. Overall, total agreement ranges between 84% and 97% (depending on the season) in discriminating clear‐sky and cloudy periods with respect to the two well‐known algorithms serving as reference. The disagreement fluctuating between 6% and 15%, depending on the season, primarily occurs while the PV module temperature is adequately high and/or when the sun is close to the horizon with many more interactions between the radiation, the atmosphere and the ground surface.

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Neural network radiative transfer solvers for the generation of high resolution solar irradiance spectra parameterized by cloud and aerosol parameters

Taylor

Kosmopoulos

Kazadzis

et al. 2016

Journal of Quantitative Spectroscopy and Radiative Transfer

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How close to detailed spectral calculations is the k-distribution method and correlated-k approximation of Kato et al. (1999) in each spectral interval?

Cited by 15 publications

References 8 publications

Estimating the photosynthetically active radiation under clear skies by means of a new approach

Estimating the photosynthetically active radiation under clear skies by means of a new approach

Detecting clear‐sky periods from photovoltaic power measurements

Neural network radiative transfer solvers for the generation of high resolution solar irradiance spectra parameterized by cloud and aerosol parameters

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