© Klaus-Werner Gurgel, University of Hamburg, Germany
A surface current field measured on an 300 m x 300 m grid by two WERA radars at Petten and Voordijk. The absolute value of the current velocity is encoded in colour-scale. For clearity, only every 4th arrow indicating the direction is shown. The oceanographic front can be seen more detailed. Gradients in current velocity up to 50 cm/s within 300 m can be observed, which is much higher than expected.
The gaps in the measurement are due to interference with the wave bouys at the Petten site: The wave buoys worked like transponders by receiving the radar signal, modulating and retransmitting it. Distortions of parts of the chirp signal lead to missing data of some ranges. However, in most cases the gaps could be filled by interpolation.