Abstract
We investigated the combined use of NOAA AVHRR-based NDVI and spaceborne SAR-based land cover information for monitoring of‘spring flush’, which is rapid growth of grass over Japanese dairy farming region. Comparison of SAR (JERS : 17 July, 30 August, ERS : 12 June 1995) and TM (14 June 1995) -derived land cover map showed that compiled data of JERS-1 SAR and ERS-1 SAR lead to an acceptable success (overall agreement : 77%) for classification of pasture, forest, and bare-field distribution in the dairy farming landscape. Temporal NDVI changes in pastures during the spring flush season (29 May-9 June 1996) were retrieved through the simple inversion of linear mixing modeling, using land cover information addition to the representative forest and bare's NDVI values and the observed AVHRR NDVI values. Validations with the high-resolution optical data (HRV : 30 May, HRV : 4 June, TM : 7 June, HRV : 10 June 1996) -derived pasture's NDVIs show the good agreements in spatial and temporal variety of the pasture's NDVIs. These results indicate that jointly use of AVHRR and SAR is an effective strategy for monitoring of short-period temporal change in pastures over temperate regions. Further exploration of additional uses of GIS complementally data to SAR based classification and applications with coordinated multi-sensor datasets in areas of even greater spatial heterogeneity are needed.
