A Methodology to Validate Coarse Resolution Biophysical Products from Multi-resolution Meris Data

Although a significant international progress has been made in the recent years, the validation of coarse resolution satellite products is still limited by the small number of available sites. Calibration of ground measurements to large areas would be a suitable complement to direct validation activities. In this study, a multi-step “bottom-up” scaling approach from local fieldlevel measurement to global comparison with satellite of biophysical variables such as fractional vegetation cover (FVC) has been developed. The study presents the different results of its application on satellite data over Europe in two different years. It exploits the unprecedented potential offered by the MERIS/ENVISAT sensor, which provides fine resolution optical data at two different spatial resolutions with a revisit time of approximately three days. Canonical correlation analysis (CCA) combined with reduced major axis (RMA) regression are used to link field-measured data and satellite data, providing unbiased estimates of FVC.