The Influence of Snow Cover on the Seasonal Variation of Global Clumping Index Products

The foliage Clumping Index (CI) quantifies the level of foliage grouping within a distinct canopy structure relative to a random distribution. It is a key structure parameter for the ecological, hydrological, and land surface models. In this study, we investigate the influence of snow cover on the seasonal variation of global CI products derived from the Moderate-resolution Imaging Spectroradiometer (MODIS) Bidirectional Reflectance Distribution Function (BRDF) parameter products using the improved RTCLSR kernel-driven model. Results indicated that the cover of snow can lead to a much larger CI and thus considerably decrease the quality of the CI product. Statistics in 2006 indicates that more than 85% low quality pixels are covered by the snow. The average CI for evergreen needleleaf forests in winter will decrease about 0.1 after deducing the influence of snow covered pixels. The influence of snow cover should be carefully considered and corrected when analyzing the seasonal variation of the global CI product.