Allow Raman Units for CTDCDOM

[DocOtak]

Needed to merge/convert the ASR data here: https://cchdo.ucsd.edu/cruise/49NZ20210713

Raman Units are dimensionless and are described in Lawaetz and Stedmon 2009: https://doi.org/10.1366/000370209788964548

[DocOtak]

I want to ask someone who might know a little more about this unit before adding it to the params list.

[DocOtak]

Reading through the paper again, single ex/em instruments cannot have Raman units. Raman units require that the instrument be able to scan through the em wavelengths of the Raman peak (371nm to 428nm)¹ for a sample of pure water at an ex of 350nm, as recommended by Lawaetz and Stedmon 2009². As per the paper, this is instrument specific and therefore not a "calibration" that can be transferred.

Looks like the CTD data were already taken care of too.

Footnotes

1. This range is for the recommended 350nm ex wavelength, See equation 1 in the paper for where the peak is for other excitation wavelengths ↩

2. Lawaetz AJ, Stedmon CA. Fluorescence Intensity Calibration Using the Raman Scatter Peak of Water. Applied Spectroscopy. 2009;63(8):936-940. doi:10.1366/000370209788964548 ↩

[eaitoro]

I have another cruise with this (49NZ20191229). It seems like the solution is to just change RU to RFU, can I just confirm that that is the case?

[DocOtak]

That one looks like bottle/discrete samples which can have Raman units, and it appears according to the cruise report that this has indeed been done, so we are in "new param" territory for that.

[DocOtak]

New evidence #54

[DocOtak]

@Klankers I would encourage you or anyone else at voiceoftheocean.org to comment directly on this issue if they have any advise.