Possible generation sites of internal solitary waves observed by ERS SAR in the central region of the Bay of Biscay

We report on a set of remote sensing observations providing evidence that internal solitary waves (ISWs) observed in the central region of the Bay of Biscay can propagate not only in the NE-SW direction as described in earlier papers, but also in the SW-NE direction, that is, in the opposite direction. Analysis of over 30 ERS SAR images of the Bay of Biscay suggests new possible generation sites for internal waves (in a region comprising 43-46°N, 2-10°W). The investigation of the generation sites is based on maps produced from the SAR imagery and on regions of critical slopes of the local topography. The amplitudes and energies of the ISWs that propagate in the SW-NE direction are comparable with those generated locally in the central Bay (and travelling in the opposite direction) that have been studied before.