Preparing the ME70 for calibration
Prior to calibration, you must check that your ME70 is fully functional.
Context
A fully functional ME70 system is vital for a successful calibration. It is necessary to measure the environmental conditions before the calibration starts.
Procedure
1 Start the ME70 program.
a Set Operation to Normal.
b Start "pinging".
c Verify that the ME70 is fully operational on all channels.
2 Measure the water salinity and temperature between the transducer and the planned depth of the calibration sphere.
3 Calculate the average salinity and temperature values, and type these into the Environment dialog box.
The sound velocity is automatically calculated by the ME70. The corresponding absorption coefficient is calculated by the echo sounder according to Francois & Garrison, JASA December 1982.
Note
When you calculate the target strength (TS), you must use the sound velocity at the depth of the sphere.
Image
Sound speed in water for different salinity values
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Sound absorption for different salinity values