Estimating inter-annual crop area variation using multi-resolution satellite sensor images

The work aimed at developing a methodology which integrates high and low spatial resolution satellite sensor data to assess inter-annual crop area variation on a regional scale. The methodology is based on the use of high spatial resolution images of the main crops for a training year joint to a long-term series of low spatial resolution NDVI images. These data allow the identification of crop specific NDVI profiles for the training year, which can be compared to low spatial resolution images of other study years to detect NDVI differences convertible into crop area variation. The method was preliminarily tested in Tuscany ( central Italy), for which five Landsat Thematic Mapper (TM)/ Enhanced Thematic Mapper (ETM+) frames and a 13-year series of 10-day National Oceanic Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) Normalized Difference Vegetation Index ( NDVI) composites were available together with reference agricultural statistics. This test demonstrated the suitability of the method for inter-annual winter crop area change estimation and revealed its potential for further improvement.