Estimating spatial distribution of radiation below the Qinghai Spruce forest canopy in Qilian Mountains using hemispherical images and Airborne LiDAR data

Solar radiation transmission plays is an important process in the energy exchange in forest ecosystem. There are a lot of transmission models developed for a single canopy, but relatively fewer models for studying spatial distribution of radiation below the forest canopy. In this paper, we used a simple model that was related to canopy cover to calculate the solar radiation below the forest canopy. At the same time, the hemispherical photography integrated with airborne LiDAR to provide a data for the model. Especially, LiDAR data was used to obtain the spatial distribution of the canopy cover. We obtained a spatial distribution of solar radiation below the Qinghai Spruce forest canopy in Qilian Mountains. Results showed that modeled average daily total radiation below the canopy was 21.614 MJ/m²d, ranging from 4.618 to 54.053 MJ/m²d in our experimental zone.