RSKderiveseapressure.m

This function calculates sea pressure from pressure and atmospheric pressure then, adds it to the data field in the RSK structure. This function requires an RSK structure that contains pressure data.

The patm argument is the atmospheric pressure used to calculate the sea pressure. A custom value can be used; otherwise, the default is to retrieve the value stored in the parameters field, or to assume it is 10.1325 dbar if the parameters field is unavailable. Starting from v3.0.0, the function also supports a variable patm input as a vector,  when that happens, input RSK must not have profile structure and the input vector should have the same length of the RSK samples.

If there is already a sea pressure channel present, the function replaces the values with the new calculation of sea pressure based on the values currently in the pressure column.