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'''Author''' : Gurvan Madec, Yevgeny Aksenov, Matthieu Leclair 

'''ticket''' : #665

'''Branch''' : [https://forge.ipsl.jussieu.fr/nemo/browser/branches/DEV_r1837_mass_heat_salt_fluxes  DEV_r1837_mass_heat_salt_fluxes ] 
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=== Description ===

Revisit the formulation of the fluxes between ocean, ice and atmosphere : an exchange of water (mass exchange) is now explicitly associated with an exchange of heat and salt content. This modification simplifies the implementation of a fully embedded sea-ice.

The main modifications concern OPA, LIM2 and LIM3. They are:

   (1) the introduction in LIM2 and LIM3 of the heat and salt content exchanged with the ocean

   (2) the suppression of emps by introducing fsalt, the salt flux at the ocean surface (only non zero below sea-ice)

   (3) the modification of the definition of qns : the non solar part of the surface heat flux takes now also into account the heat content changes due to the change in volume associated with evaporation, precipitation, ice freezing and ice melting.

   (4) the modification of trasbc module in order to take into account the above changes

This update is the NOCS.4 task (Revisit of mass and salt fluxes) due by 2nd July 2010

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=== Testing ===
Testing could consider (where appropriate) other configurations in addition to NVTK].

||NVTK Tested||!'''YES/NO!'''||
||Other model configurations||!'''YES/NO!'''||
||Processor configurations tested||[ Enter processor configs tested here ]||
||If adding new functionality please confirm that the [[BR]]New code doesn't change results when it is switched off [[BR]]and !''works!'' when switched on||!'''YES/NO/NA!'''||

(Answering UNSURE is likely to generate further questions from reviewers.)

'Please add further summary details here'

 * Processor configurations tested
 * etc----

=== Bit Comparability ===
||Does this change preserve answers in your tested standard configurations (to the last bit) ?||!'''YES/NO !'''||
||Does this change bit compare across various processor configurations. (1xM, Nx1 and MxN are recommended)||!'''YES/NO!'''||
||Is this change expected to preserve answers in all possible model configurations?||!'''YES/NO!'''||
||Is this change expected to preserve all diagnostics? [[BR]]!,,!''Preserving answers in model runs does not necessarily imply preserved diagnostics. !''||!'''YES/NO!'''||

If you answered !'''NO!''' to any of the above, please provide further details:

 * Which routine(s) are causing the difference?
 * Why the changes are not protected by a logical switch or new section-version
 * What is needed to achieve regression with the previous model release (e.g. a regression branch, hand-edits etc). If this is not possible, explain why not.
 * What do you expect to see occur in the test harness jobs?
 * Which diagnostics have you altered and why have they changed?Please add details here........

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=== System Changes ===
||Does your change alter namelists?||!'''YES/NO !'''||
||Does your change require a change in compiler options?||!'''YES/NO !'''||

If any of these apply, please document the changes required here.......

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=== Resources ===
!''Please !''summarize!'' any changes in runtime or memory use caused by this change......!''

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=== IPR issues ===
||Has the code been wholly (100%) produced by NEMO developers staff working exclusively on NEMO?||!'''YES/ NO !'''||

If No:

 * Identify the collaboration agreement details
 * Ensure the code routine header is in accordance with the agreement, (Copyright/Redistribution etc).Add further details here if required..........