Optical sensors metadata issues

[vpaba]

@nvs-vocabs/reference-tables @nvs-vocabs/parameter-codes While working on #123, a few issues were identified concerning the optical sensors which may need discussing and/or further investigating ahead of mappings creation.

1. Some codes appear to be duplicated, the only difference being the float they were mounted on (in the original Argo spreadsheet, the suffix 'AP2' in a code is associated with the precisation that the instrument is mounted on an Apex float); if this is the case, consistency within the R27 vocabulary may be hindered. It is worth noting that the instruments' data sheets from the manufacturers do not specify the type/make of float the instruments may be designed to be mounted on. Codes concerned:

• ECO_FLBB & ECO_FLBB_AP2: to note that in OceanOps, ECO_FLBB_AP2 is mathed to 6 Australian NAVIS floats as well, even if description in Argo sheet specifies that this sensor is used on Apex floats;
• ECO_FLBBCD & ECO_FLBBCD_AP2;
• ECO_FLBB_AP2 & ECO_FLBB_2k: both are designed for profiling floats applications, and both have a 2000m depth rating - only difference is that ECO_FLBB_2k is matched to PROVOR floats only, whereas ECO_FLBB_AP2 is matched to Apex floats only.

2. ECO_FLBB: in the Argo spreadsheet, this sensor is linked to parameter BACKSCATTERINGMETER_BBP; however, in the SBE sensor datasheet, a specific backscattering wavelength of 700 nm is specified. (possibly affecting also ECO_FLBB_AP2, ECO_FLBB_2k, ECO_FLBBCD_AP2, ECO_FLBBCD, ECO_FLBB2 and the MCOMS sensors).

3. ECO_BB2: no information could be found on this sensor; moreover, it is not matched to any float on OceanOps. A code for it was not created.