Transactions of The Japanese Society of Irrigation, Drainage and Rural Engineering
Online ISSN : 1884-7242
Print ISSN : 1882-2789
ISSN-L : 1882-2789
Research Papers
Definition of Abnormal Data in Evapotranspiration Estimation and Application to the Energy Balance-Bowen Ratio Method
Kouzo ITOToshisuke MARUYAMA
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2019 Volume 87 Issue 2 Pages I_159-I_167


This report proposed a new definition of abnormal data in the estimation of evapotranspiration and described the applying result of the definition for the energy balance-Bowen ratio method. Namely, the abnormal data defined that the sensible heat flux (H) and the latent heat flux (lE) are α times of the applied heat flux (Rn-G) and the abnormal range of the Bowen ratio (Bo) derived mathematically. As a result, in Bo method, the definition of this abnormal data induces that Bo is equivalent to abnormal data generated in the vicinity of -1. Also, following result clarified by applying the definition to actual data, ①The evaporation rate required for water resource and irrigation planning can be obtained if α closed 1.0∼3.0 for Bo method. ②Abnormal ratio in Bo method is remarkably much in night time than day time which coincided with the many previous researchers' experiences. ③Proposed abnormal range covers all range previously proposed by researches when choosing adequate α.

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