Rehana Khatun, Takeshi Ohta, Ayumi Kotani, Jun Asanuma, Minoru Gamo, Shijie Han, Takashi Hirano, Yuichiro Nakai, Nobuko Saigusa, Kentaro Takagi, Huimin Wang and Natsuko Yoshifuji
Release Date: December 17, 2011

Spatial variations in evapotranspiration over East Asian forest sites. II. Surface conductance and aerodynamic conductance

Rehana Khatun1), Takeshi Ohta1), Ayumi Kotani1), Jun Asanuma2), Minoru Gamo3), Shijie Han4), Takashi Hirano5), Yuichiro Nakai6), Nobuko Saigusa7), Kentaro Takagi8), Huimin Wang9) and Natsuko Yoshifuji10)

1 ) Graduate School of Bioagricultural Sciences, Nagoya University
2 ) Terrestrial Environment Research Center, Tsukuba University
3 ) National Institute of Advanced Industrial Science and Technology
4 ) Institute of Applied Ecology, Chinese Academy of Sciences
5 ) Graduate School of Agriculture, Hokkaido University
6 ) Forestry and Forest Products Research Institute
7 ) National Institute for Environmental Studies
8 ) Field Science Center for Northern Biosphere, Hokkaido University
9 ) Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences
10 ) Graduate School of Agriculture, Kyoto University

(Received: June 27, 2011)
(Accepted for publication: November 24, 2011)

Abstract:
Evapotranspiration over forest surfaces is mainly constrained by environmental and forest structural components through their influence on surface conductance (Gs) and aerodynamic conductance (Ga). Tower based eddy covariance data from 16 forest sites in East Asia (2°S to 64°N) were used to examine the sensitivity of Matsumoto and Nakai models for predicting Gs and Ga, respectively. Daytime dry-canopy data for the growing season were used in this study. Comparisons between model predictions and observed Gs and Ga showed good agreement, suggesting that the models were suitable for predicting Gs and Ga with reasonable accuracy. However, the model for Gs was unable to predict Gs accurately when soil water content was low (∼10%). In this circumstance, effective soil water content and a more comprehensive method for modelling the soil water content function must be used. Gs in East Asia was largely depended on vapour pressure deficit and secondarily on soil water content. Ga was largely affected by leaf area index compared with stand density.

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To cite this article:
Rehana Khatun, Takeshi Ohta, Ayumi Kotani, Jun Asanuma, Minoru Gamo, Shijie Han, Takashi Hirano, Yuichiro Nakai, Nobuko Saigusa, Kentaro Takagi, Huimin Wang and Natsuko Yoshifuji: “Spatial variations in evapotranspiration over East Asian forest sites. II. Surface conductance and aerodynamic conductance”, Hydrological Research Letters, Vol. 5, pp.88-92, (2011) .

doi:10.3178/hrl.5.88
JOI JST.JSTAGE/hrl/5.88
Copyright (c) 2011 Japan Society of Hydrology and Water Resources