Evaluation of selected parameterizations of aerodynamic resistance to heat transfer for the estimation of sensible heat flux at a tropical site in Ile-Ife, Nigeria

Abstract

Aerodynamic resistance to heat transfer, r_ah is a well-known and important parameter for the estimation of sensible heat flux near the earth's surface. The values are highly variable over different surface types and conditions; and routinely can be determined from semi-empirical schemes incorporating parameterizations for surface-atmosphere energy exchanges. This study evaluated the performances of seven selected parameterizations of r_ah in order to establish the influence of aerodynamic resistance in the estimates of sensible heat flux over a grass canopy. The estimated values of r_ah employing different parameterizations were used to estimate sensible heat flux and the results were compared to direct eddy covariance measurements. The findings revealed that parameterization schemes by Thom (1975) and Xie (1988) performed best for the estimation of r_ah and sensible heat flux at the study location. Schemes by Verma et al. (1976), Choudhury et al. (1986), Viney (1991) and Mahrt and Ek (1984) performed moderately, while that of Hatfield et al. (1983) had the least performance.