[Rainffall interception model of forest canopy: a preliminary study].

Abstract

Canopy interception is an important hydrological process in forest ecosystem, and its modelling is of significance to understand and estimate the rainfall interception by the canopy. In this paper, a canopy rainfall interception model was established by dividing a rain incident into a set of short period, calculating the rainfall distribution intercepted by the canopy, and educing the process of the rain incident. This model considered the effects of the dryness of canopy and trunk on the evaporation from wet canopy and trunk during one rain incident, and introduced two factors, leaf area index (LAI) and surface area of trunk per unit area of ground (SAI), when computing the evaporation. The application of the model to simulate the rainfall interception process in a Larix principis-rupprechtii plantation in Guyuan, south Ningxia Hui autonomous region of China showed that the simulated and measured throughfall were identical, and the absolute deviation between simulated and measured results was within +/- 1 mm. But, when the precipitation was smaller than 6 mm, the simulated throughfall was lower than the measured one. The values of simulated stemflow were lower than the measured values, and the relative deviation between simulated and measured values was smaller when the precipitation was larger. The process of throughfall in the forest was also simulated, with the results fitted well to the measured one.