Derivation of rice clumping index from time series MISR and MODIS directional reflectance data

Clumping index (CI) indicates the spatial distribution pattern of foliage. It is important for evapotranspiration (ET) and net primary productivity (NPP) estimation. Remote sensing methods offer an opportunity for CI estimation at the global scale. However, higher resolution and more stable temporal CI are critical for spatial and seasonal characteristic understanding of CI. In this study both 275 m MISR multi-angle reflectance product and 500 m MODIS BRDF parameter product were used for CI estimation. The CI map derived from MISR shows detailed information of spatial distribution and MODIS derived CI can effectively reflect the CI seasonal variation of rice and has good consistency with the variation tendency of field measurement CI. The combination of MISR and MODIS will help us better understanding the spatial and temporal characteristics of CI.