Integrative use of multitemporal rapideye and TerraSAR-X data for agricultural monitoring

The synergistic use of optical and SAR data for applications in agriculture and precision farming is analyzed. Plant parameters derived from optical sensors have proven to be very valuable inputs for accurate crop growth modeling and biomass monitoring. Information on the temporal development of Leaf Area Index (LAI) and structural canopy changes, such as harvest, strongly support the simulation of plant development and yield formation in a realistic and spatially distributed manner. The accuracy of LAI retrieval, based on RapidEye data using radiative transfer simulations with SLC, has been successfully validated with in-situ measurements for wheat, maize and rapeseed. Thus, LAI derived from optical data covering many fields and observing the whole crop cycle served for analyzing the sensitivity of TerraSAR-X to LAI for wheat. A high correlation between LAI values and radar backscatter especially in VV polarization was observed on field basis. Derivation of LAI from SAR-data can successfully complement LAI derived from optical data and thus stabilize the necessary data sources for plant modeling, making the data less dependent on weather conditions. Additionally, a structural indicator for the determination of the harvest date was found in the VH/VV backscatter ratio.