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Evaluation of Two Surface Renewal Methods for Calculating the Sensible Heat Flux over a Tea Field Ecosystem in Hilly Terrain.
- Source :
- Agronomy; May2023, Vol. 13 Issue 5, p1302, 13p
- Publication Year :
- 2023
-
Abstract
- Seasonal drought happens frequently in the lower slope hilly areas of China, which leads to a huge economic loss to China's famous tea production. An accurate determination of the evapotranspiration (ET) value of different seasons can provide a crucial decision parameter for irrigation management. The surface renewal (SR) method is an accurate and inexpensive method compared with the eddy covariance (EC) method, which is widely used to calculate the sensible heat flux (H). The latent heat flux (LE) evapotranspiration can be estimated indirectly when combined with the energy–balance equation. This research investigated the traditional and improved calculation methods of H (SR<subscript>snyder</subscript> and SR<subscript>chen</subscript>), based on the surface renewal theory, over a tea field for one year. The calculation accuracy was obtained from the statistical analysis between the SR and EC methods. Different months' applicability was evaluated to determine the best calculation method for the tea field. The traditional calculation method (SR<subscript>snyder</subscript>) is based on the van slope model using the second, third, and fifth structure function. The improved SR model (SR<subscript>chen</subscript>) introduces a third order temperature function and friction velocity for calculation. The results indicate that SR<subscript>chen</subscript> shows a good calculation accuracy of H in the spring seasons (February to April), summer (May to July), and autumn (August to October). The determination coefficients of regression analysis (R<superscript>2</superscript>) ranges were [0.66, 0.88] with most values greater than 0.8. The root mean square error (RMSE) ranges were [34.15, 69.22] W/m<superscript>2</superscript>. However, during this period, SR<subscript>snyder</subscript> had a poor calculation accuracy of H, and the range of R<superscript>2</superscript> was [0.45, 0.74] with the RMSE ranges of [32.28, 63.25] W/m<superscript>2</superscript>. In the winter (November to January), the calculation accuracy of both models was relatively low with R<superscript>2</superscript> almost 30% lower than that of other seasons. Therefore, this study suggests the use of the SR<subscript>chen</subscript> method to estimate the H of a tea field ecosystem in the low slope hilly area of the Yangtze River region in the spring, summer, and autumn. While in the winter, the SR<subscript>snyder</subscript> method is recommended. [ABSTRACT FROM AUTHOR]
- Subjects :
- LATENT heat
HEAT flux
DROUGHTS
STANDARD deviations
SPRING
AUTUMN
FRICTION velocity
Subjects
Details
- Language :
- English
- ISSN :
- 20734395
- Volume :
- 13
- Issue :
- 5
- Database :
- Complementary Index
- Journal :
- Agronomy
- Publication Type :
- Academic Journal
- Accession number :
- 163951733
- Full Text :
- https://doi.org/10.3390/agronomy13051302