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ARS Home » Pacific West Area » Davis, California » Crops Pathology and Genetics Research » Research » Publications at this Location » Publication #345822
Title: An intercomparison of radiation partitioning models in vineyard canopies

Author
item Parry, Christopher
item NIETO, HECTOR - Institute De Recerca I Tecnologia Agroalimentaries (IRTA)
item GUILLEVIC, PIERRE - University Of Maryland
item AGAM, NURIT - Ben Gurion University Of Negev
item Kustas, William - Bill
item Alfieri, Joseph
item McKee, Lynn
item McElrone, Andrew

Submitted to: Irrigation Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2019
Publication Date: 2/8/2019
Citation: Parry, C.K., Nieto, H., Guillevic, P., Agam, N., Kustas, W.P., Alfieri, J.G., McKee, L.G., McElrone, A.J. 2019. An intercomparison of radiation partitioning models in vineyard canopies. Irrigation Science. 37(3):239-252. https://doi.org/10.1007/s00271-019-00621-x.
DOI: https://doi.org/10.1007/s00271-019-00621-x

Interpretive Summary: Multiple radiation transfer models with unique clumping indices (a total of five approaches) were evaluated on two Pinot Noir vineyards in Central California over three years. In the first approach, a basic clumping index meant for heterogeneous randomly-placed clumped canopies was combined with the Campbell & Norman transfer model (C&N-H). The other four approaches, namely the Campbell & Norman with rectangular hedgerow clumping index (C&N-R), Campbell & Norman with a geometric elliptical hedgerow model (C&N-E), 4SAIL with row crop clumping index, and the Discrete Anisotropic Radiative Transfer (DART) models account for the unique canopy coverage distribution of the vineyard row structured canopies. Each modelling approach varied in its complexity to predict transmitted solar radiation at ground level and the outputs were compared to solar radiation measured at the surface with an array of pyranometers. All five modelling approaches showed good agreement with the measured values (correlation coefficients (r) ranged from 0.95 to 0.97). Model performance varied throughout the season due to their sensitivity to canopy growth. Although r values showed good agreement among all approaches, the C&N-E and DART models showed a better “goodness of fit” with lower root mean squared and bias values.

Technical Abstract: Multiple radiation transfer models with unique clumping indices (a total of five approaches) were evaluated on two Pinot Noir vineyards in Central California over three years. In the first approach, a basic clumping index meant for heterogeneous randomly-placed clumped canopies was combined with the Campbell & Norman transfer model (C&N-H). The other four approaches, namely the Campbell & Norman with rectangular hedgerow clumping index (C&N-R), Campbell & Norman with a geometric elliptical hedgerow model (C&N-E), 4SAIL with row crop clumping index, and the Discrete Anisotropic Radiative Transfer (DART) models account for the unique canopy coverage distribution of the vineyard row structured canopies. Each modelling approach varied in its complexity to predict transmitted solar radiation at ground level and the outputs were compared to solar radiation measured at the surface with an array of pyranometers. All five modelling approaches showed good agreement with the measured values (correlation coefficients (r) ranged from 0.95 to 0.97). Model performance varied throughout the season due to their sensitivity to canopy growth. Although r values showed good agreement among all approaches, the C&N-E and DART models showed a better “goodness of fit” with lower root mean squared and bias values.