Method for improvement of MODIS leaf area index products based on pixel-to-pixel correlations

A new method, based on pixel-to-pixel correlations, was proposed to replace unreliable Moderate Resolution Imaging Spectroradiometer (MODIS) leaf area index (LAI) time series (termed the pixel-to-pixel correction (PPC) method). MODIS LAI products improved by the PPC method were compared to field-measured LAI data. Results show that the PPC method could reduce the error associated with MODIS LAI products in relation to the original MODIS LAI product, and provide a level of accuracy that meets the most reliable quality control level criterion (quality control = 0). The PPC method performed well at correcting unrealistically high and unreliable LAI values, and performed slightly better than the upper envelope smoothing method. The corrected data were also more continuous and smoother than the raw MODIS LAI products. Thus, the PPC method can successfully reduce the uncertainty and improve the accuracy of raw MODIS LAI products.