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Title
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A computerized numerical experimental study of average solar radiation penetration in plant stands
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Author
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Abstract
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| An important problem in radiation measurements is the averaging of radiant fluxes in horizontal directions. The use of downward cumulative foliage-areal index averaged over a horizontal surface for the calculation of the average penetration of solar radiation in a plant stand underestimates penetration unless the stand is horizontally uniform. Using a computerised numerical experiment method we show that the underestimation of penetration varies with the downward cumulative foliage-areal index, the extinction coefficient, as well as the foliage distribution pattern. The results show that the underestimation is strongly pronounced for some combinations of extinction coefficient and foliage-areal index. It is also shown that the use of a penetration value averaged over a horizontal surface (P(AP)) to invert the stand foliage-areal index (LAI) by means of the logarithm formula LAI = -ln(P(AP))/k can cause large underestimation of LAI, especially in the case of large LAI. Numerical results are presented in this paper to provide a basis for calibration. |
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Language
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English
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Source (journal)
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Journal of quantitative spectroscopy and radiative transfer. - Oxford
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Publication
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Oxford
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1993
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ISSN
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0022-4073
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Volume/pages
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49
:6
(1993)
, p. 651-658
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ISI
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A1993LG39800007
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Full text (Publisher's DOI)
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Full text (publisher's version - intranet only)
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