Instrument: Secchi Disc

Dataset: 
Instrument: 
Instrument Short Name: Secchi Disc
(http://vocab.nerc.ac.uk/collection/L22/current/TOOL0430/)
Instrument Description:

Typically, a 16 inch diameter white/black quadrant disc used to measure water optical clarity

PI supplied instrument name: Secchi Disc
Dataset-specific description

At approximately local noon, a 16 inch diameter white/black quadrant disc was lowered from the ship’s deck until no longer visible and this depth (in meters) recorded as the Secchi depth