2002/01/01 by N.V. Shabanov, Nikolay V. Shabanov, Liming Zhou +6 · 1 citation
Environmental Science · #Plant Water Relations and Carbon Dynamics #Remote Sensing in Agriculture #Science and Climate Studies
paper · doi:10.1109/36.981354
openalex publication_date 2002/01/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
This paper reports on the analysis of Pathfinder AVHRR land (PAL) data set that spans the period July 1981 to September 1994. The time series of normalized difference vegetation index (NDVI) data for land areas north of 45/spl deg/ N assembled by correcting the PAL data with spectral methods confirms the northerly greening trend and extension of the photosynthetically active growing season. Analysis of the channel reflectance data indicates that the interannual changes in red and near-infrared reflectances are similar to seasonal changes in the spring time period when green leaf area increases and photosynthetic activity ramps up. Model calculations and theoretical analysis of the sensitivity of NDVI to background reflectance variations confirm the hypothesis that warming driven reductions in snow cover extent and earlier onset of greening are responsible for the observed changes in spectral reflectances over vegetated land areas.