Ramses P band and L band campaign over the Nezer forest: calibration and polarimetric analysis

Inhalt:
A SAR acquisition campaign with the ONERA RAMSES system took place in January 2004 over the Landes Forest, in Southern France. This forest is particularly well suited for biomass analysis as it has been wellmonitored over the last decades and is formed by mono-specie rectangular forest plots of different ages. P and L band data have been acquired simultaneously: The acquisition technique included deramp on receive in order to lower the data rate and allow multi-frequency simultaneous acquisition. This paper presents the calibration procedure identifying the consequences of the deramp on receive mode. The calibration parameters are computed on one image and then applied to the whole set over which an analysis of the calibration accuracy is performed. The quality of the data set is evaluated through the usual parameters and different approaches to evaluate the noiseequivalent sigma0 are proposed. The polarimetric data set is then analysed and the potential of radiometry and polarimetry for biomass evaluation is investigated. The anisotropy is found to be an excellent indicator of biomass and the analysis on the dataset does not show evidence of saturation even for the highest biomass found in this forest. Finally, a preliminary analysis for the SNR requirement associated with the proposed inversion algorithm for a P band observation satellite is performed.