Comparison of Evapotranspirations Measured by Lysimeter and Calculated by Various Estimating Methods

Abstract

The accuracy of methods for estimating evapotranspiration at upland in a humid area was investigated at a soybean field. First, hourly evapotranspiration were estimated using the Bowen ratio method, Brown‐Rosenberg method, Batholic method and Monteith method. Second, daily evapotranspiration were estimated using the Ostromeki method, Makkink method, Stephens method, Turc method, Jensen method, van Bavel method, van Bavel‐Businger method and Penman method. Correlativity between estimated and observed values was compared, and superiority of these methods was discussed. When hourly meteorological data were available, the Batholic method was accurate next to the Bowen ratio method. And when daily meteorological data were available, the Stephens method showed high accuracy next to the Penman method, though this method only use average daily temperature and daily solar radiation.