Version 10 (modified by mathiot, 7 years ago) (diff) |
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Last edited Timestamp?
Author : Mathiot
ticket : #1331
Branch : dev_r4650_UKMO2_ice_shelves
Description
Dynamics for the top layer beneath the ice shelves:
- top partial step
- top friction (same option as for the bottom friction)
- Correction of the divergence locally (as for runoff fresh water flux)
Thermodynamics used to compute the melt rate:
- ISOMIP formulation (2 equation formulation)
- 3 equation formulation (Jenkins et al. 1991)
- Forcing mode (prescribed melt rate) is available.
- Losh top boundary layer (Losch et al., 2008)
Validation configuration: ISOMIP
ISOMIP is a closed rectangular basin of uniform depth 900 m, spanning 15° of longitude, and latitudes 80° South to 70° South. The whole basin is covered with an ice shelf, with the ice draft rising linearly from 700 m at 80° South to 200 m at 76° South, and remaining constant at 200 m from 76° South to 70° South. The geometry is uniform in the east-west direction. The vertical coordinates is z . All the model setup and geometry is fully described in J.R. Hunter, 2006.
Bibliography:
- Hunter, J.R.: Specification for test models of ice shelf cavities, technical report, Antarctic Climate & Ecosystems Cooperative Research centre, version 7, 2006.
- Jenkins, A., Hellmer, H.H. and D.H. Holland: The Role of Meltwater Advection in the Formulation of Conservative Boundary Conditions at an Ice–Ocean Interface, Journal of physical oceanography, 31, 2001.
- Losch, M. Modeling ice shelf cavities in a z coordinate ocean general circulation model Journal of Geophysical Research: Oceans, 2008, 113
Reviewers:
- System reviewer: Andrew Coward
- Science reviewer: Gurvan Madec
Testing
Testing could consider (where appropriate) other configurations in addition to NVTK].
NVTK Tested | '''YES/NO''' |
Other model configurations | '''YES/NO''' |
Processor configurations tested | YES |
If adding new functionality please confirm that the New code doesn't change results when it is switched off 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: 1x8; 8x1; 1x1; 8x4; 4x8; in ISOMIP configuration (12 steps)
- Volume conservation test:
- configuration ISOMIP vvl after 1 year: volume ssh variation (km3) = ~1e-13 and vol trend (surface forcing (km3)) = 0.0
- configuration ISOMIP novvl after 1 year: volume ssh variation (km3) = ~1e-15 and vol trend (surface forcing (km3)) = 0.0
Bit Comparability
Does this change preserve answers in your tested standard configurations (to the last bit) ? | NO |
Does this change bit compare across various processor configurations. (1xM, Nx1 and MxN are recommended) | YES in ISOMIP configuration (not yet tested for the other configurations) |
Is this change expected to preserve answers in all possible model configurations? | NO |
Is this change expected to preserve all diagnostics? ,,''Preserving answers in model runs does not necessarily imply preserved diagnostics. '' | NO |
If you answered '''NO''' to any of the above, please provide further details:
- Which routine(s) are causing the difference?
- domzgr.F90: For ice shelves, I need to define the the e3t/u/v/w=zt/u/v/w(k+1) - zt/u/v/w(k). If not, dep3w(i,j,k) (could be) .NE. dep3w(i,j+1,k) in the full wet cell beneath the ice shelf.
- zpshde.F90
- dynhpg.F90
This has been only tested in GYRE configuration with bump at the bottom and ln_zps activated.
- 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.
- domzgr.F90: Need to replace definition of gdep3w_0, e3uw_0 and e3vw_0, and e3t_1d and e3w_1d by the reference 3.6 version code
- zpshde.F90: The easiest thing to do is to keep the header and the variable definition.
- dynhpg.F90: The easiest thing to do is to replace this routine by the reference 3.6 version.
- 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……..
- sst and sss are now define as the temperature of the first wet cell. In case of ice shelf it is the cell at the ice/ocean interface.
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……. Namelist changes:
!----------------------------------------------------------------------- &namsbc ! Surface Boundary Condition (surface module) !----------------------------------------------------------------------- nn_isf = 1 ! 0=no isf / 1 = presence of ISF / 2 = bg03 parametrisation / 3 = rnf file for isf / 4 = prescribed melt rate / !----------------------------------------------------------------------- &namsbc_isf ! Top boundary layer (ISF) !----------------------------------------------------------------------- ! ! file name ! frequency (hours) ! variable ! time interpol. ! clim ! 'yearly'/ ! weights ! rotation ! ! ! ! (if <0 months) ! name ! (logical) ! (T/F) ! 'monthly' ! filename ! pairing ! ! nn_isf == 4 sn_qisf = 'rnfisf' , -12 ,'sohflisf', .false. , .true. , 'yearly' , '' , '' sn_fwfisf = 'rnfisf' , -12 ,'sowflisf', .false. , .true. , 'yearly' , '' , '' ! nn_isf == 3 sn_rnfisf = 'runoffs' , -12 ,'sofwfisf', .false. , .true. , 'yearly' , '' , '' ! nn_isf == 2 and 3 sn_depmax_isf = 'runoffs' , -12 ,'sozisfmax' , .false. , .true. , 'yearly' , '' , '' sn_depmin_isf = 'runoffs' , -12 ,'sozisfmin' , .false. , .true. , 'yearly' , '' , '' ! nn_isf == 2 sn_Leff_isf = 'rnfisf' , 0 ,'Leff' , .false. , .true. , 'yearly' , '' , '' ! for all case ln_divisf = .true. ! apply isf melting as a mass flux or in the salinity trend. (maybe I should remove this option as for runoff?) ! only for nn_isf = 1 or 2 rn_gammat0 = 1.0e-4 ! gammat coefficient used in blk formula rn_gammas0 = 1.0e-4 ! gammas coefficient used in blk formula ! only for nn_isf = 1 nn_isfblk = 1 ! 1 ISOMIP ; 2 conservative (3 equation formulation, Jenkins et al. 1991 ??) rn_hisf_tbl = 30. ! thickness of the top boundary layer (Losh et al. 2008) ! 0 => thickness of the tbl = thickness of the first wet cell ln_conserve = .true. ! conservative case (take into account meltwater advection) nn_gammablk = 0 ! 0 = cst Gammat (= gammat/s) ! 1 = velocity dependend Gamma (u* * gammat/s) (Jenkins et al. 2010) ! if you want to keep the cd as in global config, adjust rn_gammat0 to compensate ! 2 = velocity and stability dependent Gamma Holland et al. 1999 / !----------------------------------------------------------------------- &nambfr ! bottom/top friction !----------------------------------------------------------------------- rn_tfri1 = 4.e-4 ! top drag coefficient (linear case) rn_tfri2 = 2.5e-3 ! top drag coefficient (non linear case). Minimum coeft if ln_loglayer=T rn_tfri2_max = 1.e-1 ! max. top drag coefficient (non linear case and ln_loglayer=T) rn_tfeb2 = 0.0 ! top turbulent kinetic energy background (m2/s2) rn_tfrz0 = 3.e-3 ! top roughness [m] if ln_loglayer=T ln_tfr2d = .false. ! horizontal variation of the top friction coef (read a 2D mask file ) rn_tfrien = 50. ! local multiplying factor of tfr (ln_tfr2d=T) /
Resources
''Please ''summarize'' any changes in runtime or memory use caused by this change……''
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……….