An assessment of ASAR for crop determination in Europe using ERS-2 and Radarsat data

This paper presents work from the contract 'ASAR and Radarsat Benefits for Crop and Area Determination in Europe (ARCADE)' undertaken by the National Remote Sensing Centre Limited (NRSC). The customer for the project was the Space Department, DERA Farnborough. The objective of this work was to quantify the potential benefits that the dual polarisation and steerable beam of ASAR instrument on board ENVISAT may bring to crop identification. A combination of ERS-2 and Radarsat data covering a site near Great Driffield in North Yorkshire, UK was used. Specifically, the results act as a first assessment of the improvement that ASAR's alternating polarisation capability and variable incidence angle will give over ERS-2. The work is based on seven data acquisition campaigns where ERS-2 and Radarsat data were gathered at seven specific intervals in the season. Ground surveys were timed to coincide with these acquisitions when broad descriptive parameters relating to the local crops and their environment were collected. All satellite data sets were radiometrically and geometrically corrected, and some comments on calibration are presented. Combinations of images were analysed and compared to assess the effects of polarisation and incidence angle on crop discrimination.