Version 33 (modified by ctlod, 12 years ago) (diff)

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ORCA2_LIM reference runs

A - Purposes:


Document the changes from ORCA2-LIM based on OPA8.2 and ORCA2-LIM base on last NEMO version
Key changes to be documented:

# Existing one :

  • partial step representation of bottom topography
  • updated TKE physics (surface/internal wave breaking)
  • new sea-ice component (LIM-3)

# Existing but not included in NEMO trunk :

  • Kz tides including ITF specific formulation (Laurent & Ariane PhD)
  • mesoscale eddy parametrisation : added in momentum equations (Aiki) (Claude/Gurvan? Japan)
  • 3 band light penetration (RGB) (Sebastian Japan)
  • Ocean color used to specified time-space varying light penetration (Sebastian Japan)
  • Diurnal cycle on qsr (from daily mean value) (Sebastian Japan)

# Forth coming one :

  • mesoscale eddy parametrisation : Griffies scheme + Visbeck coefficient (Met Office?, NOCS)
  • npc reactivation (Claude/Gurvan?)
  • conservative leap-frog (Matthieu)
  • vvl + conservative leap-frog (Matthieu)

B - Ongoing simulations:


Abstract for the simulations performed over 10 years (latest ones are the first presented):

  • for PHC_16? based on PHC_15 but :
    - apply -9% on precipitation & runoff instead of -8% in PHC_15 experiment
    
  • for PHC_15?: based on PHC_11 but :
    just use "good" input fields for K1 and M2 waves
    
  • for PHC_12 based on PHC_11 but :
    few tests to improve transport of few straits:
    - fmask = 4.0 at the output of the Baltic sea
    - fmask = 0.5 at Gibraltar
    - fmask = 1.0 at Bab El Mandeb & add an identical value at one corner of the strait
    - one specificity of the Sound strait is an annual mean output flow, so to catch it in outputs,
    few modifications have been done in the diafwb.F90 module. further more an error on the location
    of the Sound strait has been also corrected
    - 
    
  • for PHC_11: based on PHC_10 but includes both:
    it seems that input fields were not the good ones
    - global Kz tides 
    - increased Kz tides in the ITF area
    
  • for PHC_10?: based on PHC_9 but includes both:
    - 3 waves lenghts penetration (RGB) through the traqsr.F90 module 
    - ocean color: climatology of a 2D chlorophyll field
    
  • for PHC_9?: based on the PHC_8 experiment
    change the way to compute wind stress & wind module:
    - wind module is now read and corresponds to ||U||clim, i.e. the one computed using 6hourly components 
    not the one using climatological components Uclim/Vclim 
    - wind stress: (||U||.u)clim & (||U||.v)clim fields are directly read instead computed. the drag coefficient is the one 
    computed using on the wind module read just above.
    - in doing this we don't substract anymore relative velocity of the ocean/sea-ice in the computation of the wind module 
    and the wind stress
    
  • from PHC_1 to PHC_8 :
    all these runs have been used for:
    - freshwater budget adjustement in playing with new namelist parameters alpha_precip, alpha_runoff
    - Gibraltar, Bab El Mandeb & Sound sraits transports adjustement ( based on scale factors or/and bondary condition fmask )
    - they all used the following computation for the wind module:  we add the wind module variance difference 
    (||U||clim)^2 - (Uclim^2 + Vclim^2) to the computation of the wind module where ||U||clim is the climatological wind module 
    and Uclim/Vclim are the climatological wind component
    


Results from the 10th year:

Runs PHC_1 PHC_2 PHC_3 PHC_5 PHC_6 PHC_7 PHC_8 PHC_9 PHC_10 PHC_11 PHC_15 PHC_16
Precip / -10% -12% / -8% -10% -8% -8% -8% -8% -8% -9%
Evap / / / +10% +5% +10% +10% +10% +10% +10% +10% +10%
Empold (Sv) +1.88 +0.26 -0.06 +1.37 +0.31 -0.25 +0.07 +0.13 +0.1 +0.12 +0.13 -0.02
SST/rt PHC3 / / / ++ + ++ ++ ?? ?? ?? ?? ??
SSH drift (m) / / -0.006 +0.12 +0.028 -0.022 +0.006 +0.01 +0.008 +0.01 +0.01 -0.002


C - To do list/ Remaining Questions:

  • check climatological CORE bulk forcing fields computed during 1st and 2nd year
  • do moficiation to perfom annual mean outputs except the last year: OK
  • check with Martin that all ice parameters for LIM 3.0 are the best one for ORCA2_LIM.
  • ensure the upload of the STRAIT.dat file (transport through straits) : OK
  • rebuild the meshmask since the scale factors have been changed on some straits: OK

Questions to solve when setting the control simulation:

  • What are we doing with runoffs ? A: We used the standard climatology
  • freswater budget, annual correction ? A: yes, in using the previous year ssh drift.
  • Do we take into account the ice melting of Greenland and Antarctic into runoffs directly ?
  • advection scheme to use ? A: the TVD for tracers
  • define the way to manage the wind speed .vs. the sea-ice/ocean velocity, i.e do the difference of fields
  • define the relaxation time scale for the SSS restoring term and define the area i.e. (global even under sea-ice ?) Done everywhere even under sea-ice, same restorint time scale (12 days) as for SST which require a value of deds= - 864 mm/day
  • use the corrected interpolated temp/ salinity fields in Arctic from PHC for initialization suggested by Sylvain Bouillon see ticket: #227; Conkright et al. (2002) everywhere except in Arctic and Steel et al. (2001) for Arctic region data for the initialization ? (See Core paper)
  • bathymetry review ( special treatment of straits Gibraltar, Bab El ..ec ) A: yes around Gibraltar and Bab El Mandeb straits with new depth, and a reduing of scale factors.

D - Few characteristics of runs as a reminder:

  • perform internal damping (key_tradmp) ndmp = -1 around Gibraltat & Bab El Mandeb straits
  • SSS damping ln_sssr = true with a restoring time scale of 12 days (same as for SST) deds = -864 mm/day

E - Last results:

Plot of the differences between: wind module climatology and wind module computed with climatology wind speed: No image "Diff_wndm_strong_smooth_ymean.png" attached to user/ctlod/ORCA2Runs

Plot: SQUAREROOT[ Wc2 - (Uc2 + Vc2) ] where Wc is the wind module climatology, Uc & Vc are the wind speed climatology No image "Diff_wndm_variance_ymean.png" attached to user/ctlod/ORCA2Runs

F - Description of variables:

  • LIM 3.0 variables output:
    !
    !           !         title of the field           !  name     !   units   !  save  ! multipl. ! additive !
    !           !                                      !           !           ! or not !  factor  !  factor  !
       field_1  = 'Ice concentration                  ', 'iiceconc', '%       ',    1   ,  1.0     ,    0.0
       field_2  = 'Ice thickness                      ', 'iicethic', 'm       ',    1   ,  1.0     ,    0.0
       field_3  = 'Snow thickness                     ', 'isnowthi', 'm       ',    1   ,  1.0     ,    0.0
       field_4  = 'Daily bottom thermo ice production ', 'iicebopr', 'cm/day  ',    1   , 100.     ,    0.0
       field_5  = 'Daily dynamic ice production       ', 'iicedypr', 'cm/day  ',    1   , 100.     ,    0.0
       field_6  = 'Oceanic flux at the ice base       ', 'ioceflxb', 'w/m2    ',    1   ,  1.0     ,    0.0
       field_7  = 'Ice velocity u                     ', 'iicevelu', 'm/s     ',    1   ,  1.0     ,    0.0
       field_8  = 'Ice velocity v                     ', 'iicevelv', 'm/s     ',    1   ,  1.0     ,    0.0
       field_9  = 'Sea surface temperature            ', 'isstempe', 'C       ',    1   ,  1.0     , -273.15
       field_10 = 'Sea surface salinity               ', 'isssalin', 'PSU     ',    1   ,  1.0     ,    0.0
       field_11 = 'Total flux at ocean surface        ', 'iocetflx', 'w/m2    ',    1   ,  1.0     ,    0.0
       field_12 = 'Solar flux at ocean surface        ', 'iocesflx', 'w/m2    ',    1   ,  1.0     ,    0.0
       field_13 = 'Non-solar flux at ocean surface    ', 'iocwnsfl', 'w/m2    ',    1   ,  1.0     ,    0.0
       field_14 = 'Heat flux due to brine release     ', 'iocehebr', 'w/m2    ',    1   ,  1.0     ,    0.0
       field_15 = 'Wind stress u                      ', 'iocestru', 'Pa      ',    1   ,  1.0     ,    0.0
       field_16 = 'Wind stress v                      ', 'iocestrv', 'Pa      ',    1   ,  1.0     ,    0.0
       field_17 = 'Solar flux at ice/ocean surface    ', 'iicesflx', 'w/m2    ',    1   ,  1.0     ,    0.0
       field_18 = 'Non-solar flux at ice/ocean surface', 'iicenflx', 'w/m2    ',    1   ,  1.0     ,    0.0
       field_19 = 'Snow precipitation                 ', 'isnowpre', 'kg/day  ',    1   ,  1.0     ,    0.0
       field_20 = 'Mean ice salinity                  ', 'iicesali', 'psu     ',    1   ,  1.0     ,    0.0
       field_21 = 'Mean ice age                       ', 'iiceages', 'years   ',    1   ,  0.002739,    0.0
       field_22 = 'Daily lateral thermo ice prod.     ', 'iicelapr', 'cm/day  ',    1   ,100.      ,    0.0
       field_23 = 'Daily snowice ice production       ', 'iicesipr', 'cm/day  ',    1   ,100.      ,    0.0
       field_24 = 'Mean ice temperature               ', 'iicetemp', 'C       ',    1   ,  1.0     , -273.15
       field_25 = 'Ice total heat content             ', 'iiceheco', '10^9 J  ',    1   ,  1.0     ,    0.0
       field_26 = 'Ice surface temperature            ', 'iicesurt', 'C       ',    1   ,  1.0     , -273.15
       field_27 = 'Snow temperature                   ', 'isnotem2', 'C       ',    1   ,  1.0     , -273.15
       field_28 = 'Fsbri - brine salt flux            ', 'iicfsbri', 'kg/m2/s ',    1   ,  1.0     ,    0.0
       field_29 = 'Fseqv - equivalent FW salt flux    ', 'iicfseqv', 'kg/m2/s ',    1   ,  1.0     ,    0.0
       field_30 = 'Brine volume                       ', 'ibrinvol', '%       ',    1   ,  100.0   ,    0.0
       field_31 = 'Frazil ice collection thickness    ', 'iicecolf', 'm       ',    1   ,  1.0     ,    0.0
       field_32 = 'Ice strength                       ', 'iicestre', 'N/m     ',    1   ,  0.001   ,    0.0
       field_33 = 'Ice velocity                       ', 'iicevelo', 'm/s     ',    1   ,  1.0     ,    0.0
       field_34 = 'Surface melt                       ', 'iicesume', 'cm/day  ',    1   ,100.      ,    0.0
       field_35 = 'Bottom melt                        ', 'iicebome', 'cm/day  ',    1   ,100.      ,    0.0
       field_36 = 'Divergence                         ', 'iicedive', '10-8s-1 ',    1   ,  1.0e8   ,    0.0
       field_37 = 'Shear                              ', 'iiceshea', '10-8s-1 ',    1   ,  1.0e8   ,    0.0