Comparison of Forest Canopy Interception Models Combined with Penman-Monteith Equation.
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Date
2002
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Abstract
Three models of interception process: Rutter model with Deardorff's power function, Deardorff model and Modified Kondo
model, each in combination with Penman-Monteith equation applied to the same climatic forcing over the year of simulation
were compared. The modification of the Kondo's model done in our study includes the water balance component, between
storms evaporation and transpiration including the power function, storage changes and the canopy drainage. The comparison
was meant for assessing the simple Modified Kondo model developed in Japan and demonstration of the importance of the
power function. The Penman-Monteith equation was the kernel for determination of evaporation and transpiration rates. Its use
in this study was proposed because it has been widely used in Japan and in experimental sites and therefore can be used as a
basis for comparison. Since much interest was on net rainfall, the control volume for the water accounting was between top of
the canopy and above the ground surface and hence does not include soil moisture and transpiration. Results showed that forest
canopy evaporation ranged from 22 to 29% of gross rainfall. Much model prediction differences were observed in winter, with
lower rainfall intensity where wet canopy storages or rainfall did not meet the potential (atmospheric) evaporation demand.
The annual net rainfall and transpiration ranged from 71 to 78% of gross rainfall and from 727 to 733 mm respectively. The
adopted power function had significant impact on transpiration rate and small impact on evaporation rate for the Modified
Kondo model. The Modified Kondo model predicted fairly close to the two models and therefore can be used for providing
hourly input into hydrological models. The differences in the predicted hydrological fluxes resulted from the different model for
mulations especially throughfall coefficients and drainage functions.
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Keywords
Penman-Monteith equation, Closed forest canopy, LAI, Evaporation, Transpiration, Canopy water balance, Hikimi River basin, Japan
Citation
Mulungu, D. M., Shiiba, M. and Ichikawa Y., 2002. Comparison of Forest Canopy Interception Models Combined with Penman-Monteith Equation. 水文・水資源学会誌, 15(6), pp.555-568.