Validation of MODIS/LAI production based on PROSAIL model and high spatial resolution HJ-1A-CCD2 image

The present study validated accuracy of the MODIS/LAI production with resolution of 1 000 m by compared with in-situ field measurements and retrieved LAI from the PROSAIL physical model using HJ-1A-CCD2 data from China Environment and Disaster Reduction Satellite. The field measurements achieved by designed and carried out measurements of LAI in 3 km×3 km areas from the temperate meadow-steppe in Hulunber region. Heterogeneity in remote sensing data was analyzed and LAI was resampled with scaling-up method and nearest-neighbor algorithm for comparison with MODIS LAI production. The results showed that the MODIS/LAI production was overestimated according to field measurements and underestimated according to HJ-1A-CCD2/LAI data. The relative errors were 28.1% and 13.5%, respectively. The MODIS/LAI production was overestimated about 0.04 in relatively homogeneous grassland and about 0.18 in heterogeneous grassland. The relative errors were 5.8% and 32.7%, respectively. The surface homogeneous, soil background and uncertain model possibly explained these overestimation and underestimation of the MODIS/LAI production. It was necessary to validate the accuracy of MODIS/LAI production as there was bias for relative error