New variable - Silicate

[champikagallage]

Initial request

We are requesting to add the new variable Silicate which is part of ESAC-Ocean requirement in the RRR process.

Amendment details

Name: Silicate Definition: Si(OH)4 concentration in sea water

Requestor(s)

ESAC-Ocean

Stakeholder(s)

GOOS, OCG, OceanOPS

Applications or Systems

• [X] OSCAR/Surface
• [X] OSCAR/requirements
• [ ] Radar/DB
• [X] OceanOPS
• [ ] WHOS
• [ ] WDQMS
• [ ] GBON Compliance Monitor
• [ ] Other

Expected impact of change

LOW

Collaborators

No response

References

GCOS 245 (https://library.wmo.int/idurl/4/58111))

Comments

The definition in GCOS 245 for Silicate is slightly adopted to conform to the WIGOS entries for Nitrate and Phosphate.

Publication(s)

Manual on Codes (WMO-No. 306), Volume I.3, WMO Codes Registry - WMDR

Validation

No response

[joergklausen]

Suggested amendment, in line with the corresponding variable under Atmosphere. The original request is ambiguous, in that name and chemical formula provided are inconsistent.

notation	path	label	description
tbd	ObservedVariableOcean	(SiO3)2- (silicate)	IUPAC: dioxido(oxo)silane, PubChem CID: 115035, CAS Number: 15593-90-5, concentration in sea water
tbd	ObservedVariableOcean	Si(OH)4 (orthosilicic acid)	IUPAC: silicic acid, PubChem CID: 14942, CAS Number: 10193-36-9, concentration in sea water

NB: A future amendment is likely in the context of migrating names to I-ADOPT compliant variable names.

[amilan17]

https://github.com/wmo-im/tt-wigosmd/wiki/Meeting.2025.04.17 notes: Joerg noted that he proposes two variables instead of one because Silicate and Si(OH)4 are not the same; Champika will consult with ESAC-Ocean on this;

[champikagallage]

Ocean expert confirmed that Silicic acid would be more appropriate, therefor please use Si(OH)4 (orthosilicic acid) [IUPAC: silicic acid, PubChem CID: 14942, CAS Number: 10193-36-9, concentration in sea water] given in the above table (line 2).

[joergklausen]

Final draft amendment:

notation	path	label	description
tbd	ObservedVariableOcean	Si(OH)4 (orthosilicic acid)	IUPAC: silicic acid, PubChem CID: 14942, CAS Number: 10193-36-9, concentration in sea water

[amilan17]

I updated the title and amendment details

[amilan17]

@joergklausen branch is available for updating

[amilan17]

https://github.com/wmo-im/tt-wigosmd/wiki/Meeting.2025.06.12 notes:

@champikagallage review branch please