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'''Author''' : Clement Bricaud <cbricaud@mercator-ocean.fr>

'''ticket''' : #864

'''Branch''' : [https://forge.ipsl.jussieu.fr/nemo/browser/branches/2011/dev_r2802_MERCATOR10_diadct dev_r2802_MERCATOR10_diadct ] 
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=== Description ===
Online computing of transport across sections ¶

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

||NVTK Tested||!'''YES!'''||
||Other model configurations||!'''YES!'''||
||Processor configurations tested||[ 1*1,2*4,2*8 ]||
||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!'''||

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

'Please add further summary details here'

 Tests done on IBM power 6:

 * reproductiblity: ORCA2_LIM: compare 2*8 and 4*4 configurations: results are identical ( for 75 time steps, with key_mpp_rep ) 

                    GYRE : compare 2*8 and 4*4 configurations: results are identical ( for 60 time steps, with key_mpp_rep )

 * restartability: GYRE, with 1*1 configuration: compare 2 consecutives runs of 60 time steps with 1 run of 120 time steps : results are identical 
 

=== Bit Comparability ===
||Does this change preserve answers in your tested standard configurations (to the last bit) ?||!'''YES !'''||
||Does this change bit compare across various processor configurations. (1xM, Nx1 and MxN are recommended)||!'''YES!'''||
||Is this change expected to preserve answers in all possible model configurations?||!'''YES!'''||
||Is this change expected to preserve all diagnostics? [[BR]]!,,!''Preserving answers in model runs does not necessarily imply preserved diagnostics. !''||!'''YES!'''||

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 !'''||
||Does your change require a change in compiler options?||!'''NO !'''||

If any of these apply, please document the changes required here.......
add a bloc in namelist:namdct

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=== Resources ===
tests done on Dell cluster, 4*4 mpi configuration:
 * 1 year of ORCA2_LIM without diadct computing: walltime=15 minutes, mem=1.56 Go.
 * 1 year of ORCA2_LIM with    diadct computing ( 1 transport computing + writing per day, 132 sections) : walltime=21 minutes, mem=1.52 Go.

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=== IPR issues ===
||Has the code been wholly (100%) produced by NEMO developers staff working exclusively on NEMO?||!'''YES !'''||

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..........

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=== Transports Rsults on ORCA2_LIM ===

Configuration: ORCA2_LIM standard 
Experience: 
 *  1 year of simulation, restart from a 1 year spinup.
 *  Transport computed one time evey days

Reference:
 Lumpkin, Rick, Kevin Speer, 2007: Global Ocean Meridional Overturning. J. Phys. Oceanogr., 37, 2550–2562.
doi: 10.1175/JPO3130.1 

Volume transport( yearly mean, unit=Sv ):
|| Section name                   || diadct result ||  Lumpkin and al ||
|| ACC_Drake_Passage              ||   160.240     ||     129.7       ||
|| ACC_LeCap                      ||   160.678     ||     131.7       ||
|| ACC_TAS                        ||   172.822     ||     141.5       ||
|| ATL_Atlantic_48N               ||   -1.22454    ||  -0.80.8 +- 1.2 ||
|| ATL_Atlantic_26N               ||  -1.27584     ||  -0.4 +- 2.2    ||
|| ARC_Bering_Strait              ||  0.376778     || 0.8 +- 0.1      ||
|| PAC_Subarctic_Gyre_47N         ||  0.667416     || 0.4 +- 1.4      ||
|| PAC_Pacific_32S                ||  13.0719      || 14.3 +- 3.4     ||
|| IND_Indian_32S                 ||  -12.47       || -13.7+- 2.6     ||

Heat transport ( yearly mean, unit=PetaWatt ):
|| Section name                   || diadct result ||  Lumpkin and al ||
|| ACC_Drake_Passage              ||   1.43        ||     1.36+-0.09  ||
|| ACC_TAS                        ||   2.026       ||     1.85+-0.18  ||
|| ATL_Atlantic_48N               ||   0.51        ||  -0.61 +- 0.13  ||
|| PAC_Pacific_32S                ||  0.66         || 0.55 +- 0.15    ||
|| IND_Indian_32S                 ||  -1.35        || -1.55+- 0.12    ||


Salt transport:
|| Section name                   || diadct result ||  Lumpkin and al ||
|| ACC_Drake_Passage              ||   5499.41     ||     4611+-246   ||
|| ACC_TAS                        ||   5964.39     ||     5030+-414   ||
|| ATL_Atlantic_48N               ||   -26.52      ||      -23 +- 46  ||
|| PAC_Pacific_32S                ||  527.049      ||     507 +- 124  ||
|| IND_Indian_32S                 ||  -415.94      ||    -498+- 95    ||

....