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

• Published in: Journal of hydrology (Amsterdam) Vol. 348; no. 3; pp. 330 - 340
• Main Authors: Komatsu, Hikaru, Maita, Eiichi, Otsuki, Kyoichi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-01-2008; [Amsterdam; New York]: Elsevier; Elsevier Science
• Subjects: air temperature; Animal and plant ecology; Animal, plant and microbial ecology; annual forest evapotranpsiration; Biological and medical sciences; Earth sciences; Earth, ocean, space; Empirical model; estimation; Evapotranspiration; Exact sciences and technology; Forest; forested watersheds; Fundamental and applied biological sciences. Psychology; Hydrology; Hydrology. Hydrogeology; Japan; mathematical models; mean annual temperature; Synecology; temperate forests; Temperature; Terrestrial ecosystems; water balance; Water yield; Japan; Far East; Asia; Forest; Temperature; Water yield; Empirical model; Japan; Evapotranspiration; models; atmospheric precipitation; solar radiation; water balance; rain water; evapotranspiration; forests; heterogeneity; drainage basins; water yield; water resource management; prediction; temperature
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/j.jhydrol.2007.10.006

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)
=
31.4
T (°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.