Abstract:

In order to verify applicability of the revised Gash analytical model in simulating canopy interception of the Phyllostachys edulis forest in the Jinyun Mountains, the rainfall, throughfall and stemflow characteristics and their heterogeneity was measured, and the canopy interception was simulated with the revised Gash analytical model. A comparison in week cumulative rainfall and a rainfall event interception was conducted between the simulated and actual values basing on meteorological data, forest survey data during April~July of 2009. In addition, effects of the model parameter on interception was analyzed with a sensitivity analysis method. The results indicated that the cumulative gross rainfall of 29 sampled events was 531.1 mm and the mean rainfall intensity was 2.11 mm·h^-1. The measured throughfall, stemflow and canopy interception were 463.2, 6.5, and 61.4 mm, respectively. Most of the rainfalls had a low rainfall intensity, low rainfall levels, and long duration. Throughfall, stemflow and canopy interception simulated by the revise Gash model were 461.1, 6.1, and 63.9 mm, respectively. The revised Gash analytical model of rainfall interception was employed and the simulated interception values were close to the measured ones with an underestimation of 4.07%. The comparison between the simulated and the measured canopy interception per week and per rain event during the study period showed that the relative standard error in the two interceptions between the simulated and the measured ones was 5.02% and 7.13%, respectively, indicating that the Gash analytic model could be used for estimating canopy interception in the P. edulis forest in Jinyun Mountains. The simulation with the revised Gash model was impacted most by canopy cover (c), followed by mean rainfall intensity (R), canopy storage capacity (S), mean evaporation rate during rainfall (E). But the simulation was not sensitive to trunk storage capacity (S_t) and proportion of rain diverted to stemflow (p_t) since these two parameters only had a small effect on total interception.

Key words: revised Gash analytical model, Phyllostachys edulis forest, canopy intercepaion, Jinyun Mountains