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Propagation and Scattering

The study and analysis of propagation effects is a crucial issue both for performance assessment and calibration of radar systems. The Scattering and Propagation Group concentrates on the investigation of physical scattering properties of the earth's atmosphere, where most of the relevant microwave disturbances occur in the troposphere and the ionosphere. These investigations include modelling, simulation and measurement of scattering effects arising from the presence of hydrometeors (troposphere) or charged particles in a magnetic field (ionosphere). Coherent and fully polarimetric sensors are particularly suitable for measuring and predicting the above mentioned scattering and propagation effects. Algorithms are being developed and validated. The group takes part in European projects related to weather radar measurements and shares the fully polarimetric weather radar (POLDIRAD) with the Institute of Atmospheric Physics. The latter provides unique data for the development and verification of algorithms.

In the area of the research on the ionospheric propagation effects (mainly Faraday rotation), the group contributes its knowledge to the ALOS/PALSAR product quality verification. PALSAR is the first fully polarimetric spaceborne SAR sensor which operates in L-band, where propagation effects in the ionosphere are one of the most significant error sources.
A new topic is the detection of Tsunamis using microwave remote sensing techniques as a contribution to the GITEWS (German-Indonesian Tsunami Early Warning) project. The three-year study aims at the specification of new sensor concepts.

Projects and Tasks

AMPER

The AMPER (Application of Multi-parameter Polarimetry in Environmental Remote sensing) project, funded by the EU from 2003 to 2005, was a network of 9 European partner organisations like Universities, Research Centres or private companies. The objectives of the project were, beside the research in the area of multi-parameter radar polarimetry, also the training, mobility of young researchers. Here, the Institute was responsible for the overall coordination of the project and for the research contributions performed in the field of modelling and in the comprehension of atmospheric effects and distortions on coherent polarimetric radar data. Furthermore, contributions were made in the field of polarimetric target decomposition theory.

CARPE DIEM

The European project CARPE DIEM (Critical Assessment of available Radar Precipitation Estimation techniques and Development of Innovative approaches for Environmental Management) was related to the Energy, Environment and Sustainable Development Research Program of the fifth framework programme. Its objective was to improve the flood forecasting capabilities. The institute’s tasks comprised the exploitation of advanced radar capabilities to allow the enhanced assimilation of weather radar data from operational networks in hydrological and numerical weather prediction models.

ALOS PALSAR product verification

The Japanese ALOS satellite, launched by JAXA on 24 th January 2006, carries three instruments, one of them being the fully polarimetric L-band radar sensor PALSAR. Under a contract with ESA/ESRIN, the Institute has to assess the quality of ALOS/PALSAR products distributed by the European ADEN node during the commissioning phase of the instrument and to provide a set of algorithms for quality control throughout the mission lifetime.

GITEWS

The BMBF funded GITEWS (German-Indonesian Tsunami Early Warning System) project aims at the implementation of an effective Tsunami Early Warning System for the Indian Ocean, mainly off Indonesia, and integrates terrestrial seismological and geodetic observation networks with marine measurement techniques and satellite observations. The Institute's contribution is a study of current and future possibilities of Tsunami detection using ground-based or spaceborne radar sensors or the combination of such systems. The goal is to provide a comprehensive system concept by the end of 2008, which complements and refines today’s "conventional" methods.