This study was undertaken to evaluate the effects of climatic variability on inter‐annual variations in each component of evapotranspiration (
ET) and the total
ET in a temperate coniferous forest in Japan. We conducted eddy covariance flux and meteorological measurements for 7 years and parameterized a one‐dimensional multi‐layer biosphere‐atmosphere model (Kosugi
et al., 2006 ) that partitions
ET to transpiration (
Tr), wet‐canopy evaporation (
Ewet), and soil evaporation (
Esoil). The model was validated with the observed flux data. Using the model, the components of
ET were estimated for the 7 years. Annual precipitation,
ET,
Tr,
Ewet, and
Esoil over the 7 years were 1536 ± 334 mm, 752 ± 29 mm, 425 ± 37 mm, 219 ± 34 mm, and 108 ± 10 mm, respectively. The maximum inter‐annual fluctuation of observed
ET was 64 mm with a coefficient of variance (CV) of 2.7%, in contrast to relatively large year‐to‐year variations in annual rainfall (CV = 20.1%).
Tr was related to the vapour pressure deficit, incoming radiation, and air temperature with relatively small inter‐annual variations (CV = 8.2%).
Esoil (CV = 8.6%) was related mainly to the vapour pressure deficit.
Ewet was related to precipitation with large inter‐annual variations (CV = 14.3%) because of the variability in precipitation. The variations in
Ewet were counterbalanced by the variations in
Tr and
Esoil, producing the small inter‐annual variations in total
ET. Copyright © 2016 John Wiley & Sons, Ltd.
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