Comparison of Forest Canopy Interception Models Combined with Penman-Monteith Equation.

Abstract

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.

A physically based distributed subsurface–surface flow dynamics model for forested mountainous catchments

“…Although the model was initially constructed for forested areas, it can easily be extended to other land covers. The main contributions of this study include the incorporation of a canopy interception model that considers the nature of rainstorms in Japan (Mulungu et al, 2002), the net rainfall partition between the vertical and horizontal flow (preferential flow and return flow) processes, and soil-moisture-controlled transpiration rates that consider the forest root depth and the dynamics of the water table.…”

“…A single-layer P-M equation was used to simulate evapotranspiration. Canopy interception is simulated by a combination of the P-M equation and the modified probabilistic interception model (Mulungu et al, 2002). The modified model included the water balance, evaporation and transpiration between storms taking into account the power function of Deardorff (1978), storage changes and canopy drainage.…”