Surface renewal estimates of evapotranspiration. Tall canopies

被引：18

作者：

Spano, D ^{[1
]}

Duce, P ^{[1
]}

Snyder, RL ^{[1
]}

Paw, KT ^{[1
]}

机构：

[1] Univ Sassari, Ist Coltivaz Arboree, I-07100 Sassari, Italy

来源：

SECOND INTERNATIONAL SYMPOSIUM ON IRRIGATION OF HORTICULTURAL CROPS, VOLS 1 AND 2 | 1997年 / 449期

关键词：

sensible heat flux; energy balance; eddy covariance; coherent structures; structure functions;

D O I：

10.17660/ActaHortic.1997.449.7

中图分类号：

S3 [农学（农艺学）];

学科分类号：

0901 ;

摘要：

Sensible heat flux density (H-SR) was determined over grapevine and avocado tree canopies using the surface renewal (SR) method that was first proposed by Paw U and Brunet (1991). The method employs high frequency temperature measurements above canopies to calculate H values using a conservation of energy equation. The H-SR estimates increased with measurement height above the canopies, and a calibration factor (a) was needed to improve H estimates. This a is believed to result from unequal heating of the mean air volume under the measurement height. The grapevines have a sparse canopy, whereas the avocado orchard has a dense canopy. This may explain the difference in observed a values. However, more research is needed to better understand a. Evapotranspiration (lE(SR)) was calculated using net radiation and soil heat flux density and H-SR in the energy balance equation. An independent measure of H, obtained from a sonic anemometer, was used to calculate evapotranspiration (lE) for comparison with lE(SR) values. High correlations were observed between lE(SR) and lE for both crops. When the a values were used to determine H-SR and a regression of lE(SR) versus lE was computed, the coefficient of determination values were R-2 = 0.96 for avocado trees and R-2 = 0.93 for grapevines.

引用

页码：63 / 68

页数：6