Modeling canopy interception of Picea crassifolia forest in Qilian mountains using QuickBird satellite data

Canopy interception of rainfall plays an important role in hydrologic cycling and water balance of ecosystems in arid and semi-arid regions. At present, most research focuses on the characteristics of interception at the stand or plot scale. Studies of canopy interception at the river basin or landscape scale based on RS and GIS are lacking because the factors influencing canopy interception such as precipitation, vegetation are difficult to model spatially. A semi-theoretical and semi-empirical model of canopy interception was improved based on investigation in the study area. Considering the important influence of canopy structure, LAI was introduced to the model. After parameters in the model were spatialized using remote sensing data and GIS, the spatial distribution of canopy interception was estimated in the study area (i.e. Pailugou catchment). The results show that the amount of canopy interception in Pailugou catchment is between 97.9 mm and 236.6 mm and the mean interception amount is 161.8 mm. The minimum interception appears at the lower altitude area and the maximum interception presents at the higher altitude area. The interception percentage of Picea crassifolia forest is between 27.92% and 58.00%, which increases with increasing altitude and the maximum appears at 3100m, then decreases along with the increase of altitude.