|Filling in the gap - the white triangle|
Since then our plans have changed and we are now gathering multibeam echosounder data for an area of the Western Channel rMCZ for which we don't have detailed data. The multibeam data provides an acurate picture of the shape of the seabed, but the 'backscatter' of the echoes can be further analysed to give an indication of what the seabed type is. This can then the confirmed ("ground-truthed") by the camera and grab samples that we've already taken.
|Indicative survey lines - there are really 30+ lines|
Two echo-sounder systems working at different frequencies are being run at the same time. Between them they generate about 400mb of data per hour, which means there is a lot of processing work to be done to produce the final images. To get accurate results a number of additional factors have to be compensated for: sound velocity through the water, ships heading, tidal height, and ships motion.
Ultimately, the processed data will yield a detailed seabed image. The example below shows an area north of Anglesey.
|Drumlins, north of Anglesey|