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which equation is used in adisit

Added by Stephanie Guinehut almost 7 years ago

Hi,
Could you tell me which equation is used in ADISIT: Potential temperature to in-situ temperature and vice versa.
Thanks!


Replies (11)

RE: which equation is used in adisit - Added by Stephanie Guinehut almost 7 years ago

Hi Ralf,
Thanks for your response.
Another algorithm is now broadly used: TEOS-10. Do you think it could be implemented as a new function in cdo?
Software is available for download: http://www.teos-10.org/software.htm
Thanks,
Stephanie

RE: which equation is used in adisit - Added by Ralf Mueller almost 7 years ago

Hi again!
I had a look into it and will talk to the other CDO developers about the TEOS software. It seems to be much more than a formular for rhopot ;-). I'm still not sure, if/how this could go into CDO, sorry.

regards
ralf

RE: which equation is used in adisit - Added by Anne Moree about 3 years ago

The above link to the implementation does not work anymore. adisit can be used for other models as well after changing the variable names, but it is unclear which equation is used and what the units of temperature and salinity should be. Could this be added to the documentation?

RE: which equation is used in adisit - Added by Anne Moree about 3 years ago

Anne Moree wrote in RE: which equation is used in adisit :

The above link to the implementation does not work anymore. adisit can be used for other models as well after changing the variable names, but it is unclear which equation is used and what the units of temperature and salinity should be. Could this be added to the documentation?

The info is here:

https://code.mpimet.mpg.de/projects/cdo/repository/cdo/revisions/38c114e303ac99667cbecb7e5b49264faa104956/entry/src/Adisit.c

Bryden, 1973, "New polynomials for thermal expansion, adiabatic temperature gradient and potential temperature of sea water". Deep Sea Research and Oceanographic Abstracts. 20, 401-408 (GILL P.602)

As far as I can see (please confirm), units are psu and degrees C for both input and output

RE: which equation is used in adisit - Added by Anne Moree about 3 years ago

Looking closer I think 'tho' (input potential temperature) is in degrees C and 'to' (output insitu temperature) is in degrees K

RE: which equation is used in adisit - Added by Anne Moree about 3 years ago

Hi Ralf, thank you for the new link. I had a look but still feel unsure about the units of the in and output temperature. Could you please confirm?

RE: which equation is used in adisit - Added by Ralf Mueller about 3 years ago

Input is in degC I am sure about this. And I don't see any hint for a unit-conversion in the code. So I guess the output is also degC

RE: which equation is used in adisit - Added by Anne Moree about 3 years ago

great, thanks! I became unsure when seeing the 'cdiDefKeyString(vlistID2, tisID2, CDI_KEY_UNITS, "K");' but I will then assume all is in degrees C. Thanks again and have a nice day

RE: which equation is used in adisit - Added by Ralf Mueller about 3 years ago

when I run the on degC data I get this

cdo infov -selname,to, -adisit ts_phc3.0_annual_icon_OceanOnly_Global_IcosSymmetric_0039km_rotatedZ37d_BlackSea_Greenland_modified_srtm30_1min.nc_Ln64.nc
cdo(1) selname: Process started
cdo(2) adisit: Process started
    -1 :       Date     Time   Level Gridsize    Miss :     Minimum        Mean     Maximum : Parameter name
     1 : 2000-01-01 00:00:00       6   235403       0 :     -1.7694      18.126      29.533 : to            
     2 : 2000-01-01 00:00:00      17   235403       0 :     -1.7648      17.998      29.436 : to            
     3 : 2000-01-01 00:00:00      27   235403       0 :     -1.7834      17.804      29.390 : to            
     4 : 2000-01-01 00:00:00      37   235403       0 :     -1.8185      17.497      29.355 : to            
     5 : 2000-01-01 00:00:00      47   235403       0 :     -1.8553      17.153      29.330 : to            
     6 : 2000-01-01 00:00:00      57   235403       0 :     -1.8785      16.756      29.274 : to            
     7 : 2000-01-01 00:00:00      67   235403       0 :     -1.8853      16.336      29.197 : to            
     8 : 2000-01-01 00:00:00      77   235403       0 :     -1.8912      15.915      29.088 : to            
     9 : 2000-01-01 00:00:00      87   235403       0 :     -1.8929      15.494      28.850 : to            
    10 : 2000-01-01 00:00:00      97   235403       0 :     -1.8945      15.072      28.659 : to            
    11 : 2000-01-01 00:00:00   107.5   235403       0 :     -1.8856      14.658      28.330 : to            
    12 : 2000-01-01 00:00:00     119   235403       0 :     -1.8711      14.217      27.914 : to            
Hence it cannot be Kelvin. I will discuss this with my colleagues and come back to you

cheers
ralf

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