Proposed New International Equation of State, TEOS-10

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Proposed New International Equation of State, TEOS-10

#1 Post by arango »

The following is an e-mail that we received from Trevor J. McDougall (on behalf of SCOR/IAPSO WG127):

The SCOR/IAPSO Working Group 127 on the thermodynamic properties of seawater has completed much of its work. The new thermodynamic description of seawater is now out for comment from the oceanographic community.

A document, Thermodynamic_Manual_09Jan09, can be downloaded from the CDIAC :arrow: website as described below in the message from Maria Hood of UNESCO. Your comments will be very welcome; there is a way of registering your comments on that site. The IOC will take these comments into account when the nations decide in June on the adoption of TEOS-10. The computer code (in FORTRAN and MATLAB) that implements the new approach is available from the following :arrow: website.

Two of the basic papers that underlie the new thermodynamic description of seawater; and other manuscripts can be downloaded from the above :arrow: website. The Thermodynamic_Manual is the best entry into this subject. Pages 5-9 introduce and motivate the work and the next 30 pages summarize the main results. Another 80 pages of appendices are mostly in the nature of reference material which will not be central to the normal oceanographic user.

If the new approach to defining the thermodynamic properties of seawater is well received by the community, we would hope that TEOS-10 will become the internationally accepted definition of seawater from 1st January 2010.

The most obvious change in practice, obvious to the normal oceanographic user, will be the changed salinity variable. While Practical Salinity will still be the salinity variable that is stored in national data bases (much as in situ temperature is stored in these data bases), it is Absolute Salinity that will be used in journal publications, in numerical ocean models and in inverse models (just as we do not use in situ temperature, but rather, we use potential temperature for these purposes). The main reason for adopting the new salinity variable is to allow for the spatial differences in seawater composition; this variable composition affects conductivity differently to how it affects density, enthalpy, entropy etc.

Please distribute this email and it s attachments to your colleagues in your laboratory and your country. We wish to receive a large number of comments on this work.

With best wishes,

Trevor J McDougall (on behalf of SCOR/IAPSO WG127)
Dear hydrography enthusiasts,

Several chapters of the revised hydrography manual are now on-line and ready for open community review. The remaining chapters should be available by March, and the review period will be extended to May 2009 to finalize the manual by September.

The chapters are posted at :arrow: CDIAC, and instructions about how to use the system are available on the first page. (The site is best viewed with Internet Explorer).

Username = editor
Password =

If you have any problems with the site, please contact Alex Kozyr at CDIAC (

The following chapters are now available:

1. Reference-quality water sample data: Notes on Acquisition, Record Keeping, and Evaluation -> Data_Evaluation_reference.pdf

2. Standards and Laboratory Calibration -> Data_Evaluation_reference.pdf

3. Calculation of physical properties of seawater -> Thermophysical_Manual_05Jan09.pdf

4. Salinity measurements -> Sal Kawano_081031.doc

5. A Manual for Acquiring Lowered Doppler Current Profiler Data -> 2008-11-18.pdf

6. Meteorological measurements -> fluxhandbook_NOAA-TECH20PSD-311v3.pdf

Several other chapters are in final preparation and will be added to the site in several weeks. I will send a message to the list as each new chapter is added.

Best regards,

Maria Hood,
Intergovernmental Oceanographic Commission UNESCO

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