A model to estimate annual forest evapotranspiration in Japan from mean annual temperature

Hikaru Komatsu, Eiichi Maita, Kyoichi Otsuki

Research output: Contribution to journalArticlepeer-review

51 Citations (Scopus)


In Japan, forested areas are usually located upstream of urban and agricultural areas. Estimating annual water yield from such forested areas is therefore crucial for water resources management. For this purpose, estimating annual forest evapotranspiration is required. We developed an empirical model for estimating annual forest evapotranspiration E in Japan based on 43 catchment water balance datasets summarized from earlier publications. The model formulated E as E (mm) = 31.4T (°C) + 376, where T is mean annual air temperature. This model estimated E observed in forest catchments with an average 6% error relative to incident annual precipitation. This error was comparable to or smaller than the error included in precipitation data due to the spatial heterogeneity of precipitation. High-quality air temperature data are commonly available in Japan, thus this model is a practical tool for annual water yield estimates from forested areas and therefore water resources management.

Original languageEnglish
Pages (from-to)330-340
Number of pages11
JournalJournal of Hydrology
Issue number3-4
Publication statusPublished - Jan 15 2008

All Science Journal Classification (ASJC) codes

  • Water Science and Technology


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