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Present scientific knowledge 
Since the launching of ERS-1, various studies have shown that radar data are suitable in 
principle for applications in coastal areas. The TIDE project is aimed at investigating the 
possible operational use of remote-sensing data in the performance of the above tasks. This 
involves use of the following remote sensed data: 
As input data: topography and wind 
As comparative data: water level, pattern of current speed, sediment concentration, waves. 
All SAR images taken of the Elbe estuary in the German Bight are recorded by the DFD 
receiving station Neustrelitz, processed at DFD, and evaluated with respect to the above 
parameters. 
Products 
Topography of the tidal flats of the Elbe estuary, 100 x 100 km charts of meso-scale wind 
fields with a resolution of 500 m, two-dimensional wave spectra in the wave length range from 
100 m to 1000 m. 
DLR-P4: ERS radar observations of wave attenuation due to sea ice 
Objectives 
This project is aimed at gaining new information on interactions between waves and sea ice in 
order to improve predictions and obtain a precise representation of wind, wave and sea ice 
fields which are needed for climate studies. 
he research will be carried out in co-operation with European partners in the COST Action 
714 - determination of the directional spectra of sea waves. 
Present scientific knowledge 
The active microwave systems of the ERS satellites provide the following continuous, global 
data on wind, waves, and sea ice: 
synthetic aperture radar: two-dimensional wave spectrum, sea ice distribution 
scatterometer: force and direction of wind 
altimeter: wave height and wind speed. 
Radar data of the sea surface and conventional measurements are planned to be assimilated in 
existing wave, weather and ice prediction models. 
To determine the sea state from complex SAR data, non-linear inversion methods are used to 
derive wave spectra from the image spectra. To that end, also the wave mode SAR images (5 
x 10 km size) are evaluated which are recorded globally every 200 km along the satellite orbit. 
This is done by processing the complex wave mode images with the SAR processor BSAR 
which has been developed at DFD. 
Product 
High-resolution, near-shore, meso-scale wave fields in the 100 x 100 km image mode; wave 
fields at the ice edge; global 2-dimensional wave spectra in wave mode; charts of the sea ice 
margin.