In this paper the validation and approbation of the method for estimating the latent and sensible heat fluxes over the vegetation surface in the daytime were carried out. The effect of stratification of the surface air layer on the accuracy of the calculations was investigated. The method for calculating the latent heat flux is based on the energy balance equation and includes an estimation of the thermal stability parameters using the Monin-Obukhov lenght, which is estimated by the iteration method based on experimental data. Validation of calculations was carried out according to the eddy covariance measurements on a flux station located in the state of Nebraska (USA). This station is located on an agricultural field. The model efficiency index (Nash-Sutcliffe index) for the latent heat flux without stratification is 0.55, with a stratification of 0.80; Wilmott's index of agreement is 0.91 and 0.96; root mean square error is 102.6 W/m² and 68.7 W/m², respectively. The model efficiency index (Nash-Sutcliffe index) for the sensible heat flux without stratification is -1.34, with a stratification of 0.37; Wilmott's index of agreement is 0.76 and 0.88; root mean square error is 102.4 W/m² and 53.3 W/m², respectively. The method has been tested on amaranth, canola and corn in the Leningrad Region under various stratification conditions. An unstable stratification was observed over the corn field, a neutral stratification was observed above the amaranth field, and the stratification was stable over the canola field. An oasis effect was observed over the corn field, the crop surface temperature was lower than the air temperature, which led to negative values of sensible heat flux.

Kozyreva Lyudmila Vladimirovna, Candidate of Sciences (Technical), Leading Researcher, Agrophysical Research Institute, 14, Grazhdansky Ave., Saint-Petersburg, 195220, Russian Federation, tel.: 8 (812) 534-13-24, e-mail: 4ludak@gmail.com

Dobrokhotov Aleksei Vyacheslavovich, Researcher, Agrophysical Research Institute, 14, Grazhdansky Ave., Saint-Petersburg, 195220, Russian Federation, tel.: 8 (812) 534-13-24, e-mail: dobralexey@gmail.com

Kozyreva L.V., Dobrokhotov A.V. Parameterization of the Latent and Sensible Heat Fluxes in a Stratified Atmospheric Surface Layer above the Vegetation Surface. The Bulletin of Irkutsk State University. Series Earth Sciences, 2019, vol. 30, pp. 26-37. https://doi.org/10.26516/2073-3402.2019.30.26 (in Russian)

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