Modeling and measurement of two-layer-canopy interception losses in a subtropical mixed forest of central-south China

The original Gash analytical model and the sparse Gash's model have been applied to simulate rainfall interception losses from the two canopy layers in Shaoshan forest of central-south China during 2003. The total estimated interception loss from the two canopy layers is 478.4 mm with an error of 12.4 mm or 2.7% of total measured interception loss (466.0 mm). Both the original Gash model for top-canopy interception loss and the sparse model for sub-canopy loss overestimate interception losses. The simulated results show that the interception losses in top-canopy is 182.6 mm with an overestimation of 4.9% of measured losses and that in sub-canopy is 295.8 mm with an overestimation of 1.3%. The simulated values of the top-canopy suggest that 47% of the simulated interception losses are evaporated in the stage of "during storms" and 38% in "after storms", which is similar to the published results in temperate and tropical forests. However, the modelled losses from the sub-canopy show that 17% of interception losses are evaporated in "during storms" and 70% in "after storms", which is deviated from the reported results. The simulated results of two canopy interception losses in Shaoshan forest indicate that canopy structures may strongly impact hydrological fluxes in forested ecosystems.