Development of Snow Retrieval Algorithms for CoReH2O CCN1 - Processing and Analysis of March 2011 Data: Report on SSG Modifications for SnowSAR

Abstract

This report describes the technical basis for generating simulated backscatter data that are matching the imaging characteristics of the airborne SnowSAR sensor. A main motivation for this technical development has been the retrieval of maps of snow water equivalent (SWE) from SnowSAR data, acquired on 15 March 2011 in Sodankylä. The algorithm for retrieval of SWE in winter requires as input also backscatter maps from a date close to the start of the snow season (background signal of bare ground). Because SnowSAR was only deployed in March 2011, the backscatter images representing the background medium at the beginning of the 2010/11 snow season had to be simulated. The approach for simulating SnowSAR images employs the CoReH2O Synthetic Scene Generator (SSG) with various modifications which are described in this report. In this particular case TerraSAR-X images are used as input for the SSG to simulate X-band SnowSAR images for the Sodankylä test area. In order to compute simulated SnowSAR images in the Ku-band channels, relations between X-band and Ku-band backscatter values are applied which take into account surface roughness estimates.