Monitoring of winter crop status in Bulgaria using a series of NOAA AVHRR NDVI images

The study is an application of satellite remote sensing methods for monitoring winter crops in Bulgaria over the time period 1997-2008 based on 7-day NOAA AVHRR NDVI level 3 satellite imagery. A satellite image geodatabase was created in ArcGIS/ArcInfo 9.2 and was supplemented with ground-based phenological data. The monitoring is focused on vegetation status and stress situations, making use of vegetation condition index (VCI) images obtained from the NDVI time series. The VCI images covered the four main phenophases of winter crops for the agricultural years 2006-2007 and 2007-2008. By analyzing the average values of these VCI images, the status of each phenophase for the considered years was assessed. The results pointed to drought conditions for 2006-2007 and favourable to optimal conditions for 2007-2008.