Monitorización de cereales de secano mediante observaciones de teledetección radar

Abstract

Cereals are very important crops worldwide. Their management and cropping techniques could improve if recent innovations in the field of remote sensing (and others) were applied. In the last decades, several space agencies have made a bet on the use of SAR (Synthetic Aperture Radar) technology (in combination or substitution of optical imagery) for earth observation. Therefore, it is necessary to evaluate the utility of this imagery for a range of applications. In particular, this project is focused on evaluating the utility of X-band SAR imagery for the monitoring of wheat and barley crops. To do this, several crop variables (phenology, biomass or canopy height) have been measured in situ, and next have been confronted with backscattering coefficient (σ 0) values observed in different polarizations (VV and VH). TerraSAR-X images (obtained with a 42º incidence angle) were geometrically and radiometrically corrected using specific image processing software. The results obtained, illustrate a distinct behavior of cereals depending on their phonological stage. On the first phases, a clear σ0 attenuation is observed in VV polarization, whereas VH shows a rather insensitive behavior. From the booting stage onwards, and especially after heading, a more dispersed behavior is observed in both polarizations. This is due to the low penetration capacity of microwaves at this band and incidence angles, thus providing information only on the most shallow plant constituents.