| Version 7 (modified by mathiot, 10 years ago) (diff) |
|---|
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?
- XXXX TODO
- 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.
- XXXX TODO
- 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..........
