Sea pressure
Sea pressure is the difference between the pressure measured underwater by your RBR instrument and atmospheric pressure. The units of measurement are dbar (decibars).
\[\text{Sea pressure} = \text{absolute pressure} - \text{atmospheric pressure}\]
where pressure (in dbar) is the value measured directly by your RBR instrument.
Enter atmospheric pressure (in dbar) manually in the table under Calibration > Parameter in Ruskin. See Ruskin User Guide: Standard Instruments⁴. If not entered, a default value of 10.1325dbar will be used.