Assessing sar calibration requirements over land using geophysical retrieval algorithms
 
Relevance:
 
The context for this study is provided by current preparation activities for future ESA EO SAR missions including Sentinel-1 and TerraSAR L. A recurring challenge in the definition of SAR missions is transforming the requirements of the applications into SAR instrument specification. This is particularly true for land applications such as soil moisture, land use classification, forest monitoring and others, where the accuracy of the algorithms used is often poorly assessed and requirements on the SAR instrument difficult to define. In particular, unlike certain ocean applications such as sea wind retrieval, relating instrument configuration requirements including calibration to errors in geophysical parameters is not often studied.  
 
Description:
 
In this study existing algorithms for land applications will be reviewed and a selection will be made. The accuracy of the selected algorithms will be assessed. The availability of airborne SAR and in-situ data from recent campaigns is expected to contribute to this assessment. Following this, a critical assessment of SAR instrument requirements including calibration will be performed. The focus will be on using the retrieval algorithms to transform instrument errors into geophysical uncertainties, and assess what the threshold uncertainties are for the application.