Dear All,

In 2017 we introduced quite a number of new standard names for the CMIP6 OMIP 
project. I have been informed that one name is missing from the list of 
required terms:
square_of_sea_surface_salinity (canonical units: 1e-6)
'The phrase "square_of_X" means X*X. Sea surface salinity is the salt 
concentration of sea water close to the sea surface, often on the Practical 
Salinity Scale of 1978. However, the unqualified term 'salinity' is generic and 
does not necessarily imply any particular method of calculation. The units of 
salinity are dimensionless and the units attribute should normally be given as 
1e-3 or 0.001 i.e. parts per thousand. Sea surface salinity is often 
abbreviated as "SSS". For the salinity of sea water at a particular depth or 
layer, a data variable of "sea_water_salinity" or one of the more precisely 
defined salinities should be used with a vertical coordinate axis. There are 
standard names for the precisely defined salinity quantities: 
sea_water_knudsen_salinity, S_K (used for salinity observations between 1901 
and 1966), sea_water_cox_salinity, S_C (used for salinity observations between 
1967 and 1977), sea_water_practical_salinity, S_P (used for salinity 
observations from 1978 to the
  present day), sea_water_absolute_salinity, S_A, sea_water_preformed_salinity, 
S_*, and sea_water_reference_salinity. Practical Salinity is reported on the 
Practical Salinity Scale of 1978 (PSS-78), and is usually based on the 
electrical conductivity of sea water in observations since the 1960s. 
Conversion of data between the observed scales follows: S_P = (S_K - 0.03) * 
(1.80655 / 1.805) and S_P = S_C, however the accuracy of the latter is 
dependent on whether chlorinity or conductivity was used to determine the S_C 
value, with this inconsistency driving the development of PSS-78. The more 
precise standard names should be used where appropriate for both modelled and 
observed salinities. In particular, the use of sea_water_salinity to describe 
salinity observations made from 1978 onwards is now deprecated in favor of the 
term sea_water_practical_salinity which is the salinity quantity stored by 
national data centers for post-1978 observations. The only exception to this is 
where the
  observed salinities are definitely known not to be recorded on the Practical 
Salinity Scale. The unit "parts per thousand" was used for 
sea_water_knudsen_salinity and sea_water_cox_salinity.'

This name and definition are closely related to the existing name 
sea_surface_salinity. I think this name looks fine and is unlikely to prompt 
discussion. Unless any objections are received within the next seven days, this 
name will be accepted for inclusion in the standard name table and added in the 
April update.

Best wishes,
Alison

------
Alison Pamment                                 Tel: +44 1235 778065
NCAS/Centre for Environmental Data Archival    Email: [email protected]
STFC Rutherford Appleton Laboratory     
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.

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