Namelists Modifications
Abstract
In this fourth tutorial of the NEMO SURGE demonstrator, we cover the changes to the namelist_cfg required to perform the AMM12_surge example simulation.
Namelist
Below we discuss the important changes to the namelist_cfg required for the AMM12 1-layer barotropic storm surge model.
Two modified namelist_cfg files are available in the SURGE_demo/namelists/nemo/ directory.
Let's add links to these files in our run directory:
cd nemo_5.0.1/cfgs/AMM12_SURGE/EXP00/
ln -s .../SURGE_demo/namelists/nemo/namelist_cdf_SURGE .
ln -s .../SURGE_demo/namelists/nemo/namelist_cdf_SURGE_NO_TIDES .
Temperature & Salinity (&namtsd)
- Initialise our 1-layer regional model using constant temperature (10 degrees C) and salinity (35 PSU) from the
init_state_AMM12_SURGE_y2012.ncfile created in Atmospheric Forcing Creation
.
!-----------------------------------------------------------------------
&namtsd ! Temperature & Salinity Data (init/dmp) (default: OFF)
!-----------------------------------------------------------------------
! ! =T read T-S fields for:
ln_tsd_init = .true. ! ocean initialisation
ln_tsd_dmp = .false. ! T-S restoring (see namtra_dmp)
cn_dir = './' ! root directory for the T-S data location
!___________!_________________________!___________________!___________!_____________!________!___________!__________________!__________!_______________!
! ! file name ! frequency (hours) ! variable ! time interp.! clim ! 'yearly'/ ! weights filename ! rotation ! land/sea mask !
! ! ! (if <0 months) ! name ! (logical) ! (T/F) ! 'monthly' ! ! pairing ! filename !
sn_tem = 'init_state_AMM12_SURGE', -1. , 'votemper', .false. , .false. , 'yearly' , '' , '' , ''
sn_sal = 'init_state_AMM12_SURGE', -1. , 'vosaline', .false. , .false. , 'yearly' , '' , '' , ''
/
Surface Boundary Conditions (&namsbc)
-
Use flux formulation to impose surface boundary conditions (
ln_flx) and take the atmospheric pressure into account when computing the surface pressure gradient (ln_apr_dyn). -
Hourly zonal (
utau) and meridional (vtau) wind stress is read from daily files generated in Atmospheric Forcing Creation. -
Dummy surface heat (0 W m-2) and freshwater fluxes (0 kg s-1 m-2) are read as climatologies from annual file.
!-----------------------------------------------------------------------
&namsbc ! Surface Boundary Condition (surface module) (default: NO selection)
!-----------------------------------------------------------------------
nn_fsbc = 1 ! frequency of SBC module call
ln_flx = .true. ! flux formulation (T => fill namsbc_flx)
ln_traqsr = .false. ! Light penetration in the ocean (T => fill namtra_qsr)
ln_ssr = .false. ! Sea Surface Restoring on T and/or S (T => fill namsbc_ssr)
ln_rnf = .false. ! runoffs (T => fill namsbc_rnf)
ln_apr_dyn = .true. ! Patm gradient added in ocean & ice Eqs. (T => fill namsbc_apr )
/
!-----------------------------------------------------------------------
&namsbc_flx ! surface boundary condition : flux formulation
!-----------------------------------------------------------------------
cn_dir = './fluxes/' ! root directory for the fluxes data location
!___________!_________________________!___________________!___________!_____________!________!___________!__________________!__________!_______________!
! ! file name ! frequency (hours) ! variable ! time interp.! clim ! 'yearly'/ ! weights filename ! rotation ! land/sea mask !
! ! ! (if <0 months) ! name ! (logical) ! (T/F) ! 'monthly' ! ! pairing ! filename !
sn_utau = 'amm12_surge_utau' , 1. , 'utau' , .true. , .false., 'daily' , '' , '' , ''
sn_vtau = 'amm12_surge_vtau' , 1. , 'vtau' , .true. , .false., 'daily' , '' , '' , ''
sn_qtot = 'AMM12_SURGE_dummy_flx' , -12 , 'sonsfldo', .false. , .true. , 'yearly' , '' , '' , ''
sn_qsr = 'AMM12_SURGE_dummy_flx' , -12 , 'soshfldo', .false. , .true. , 'yearly' , '' , '' , ''
sn_emp = 'AMM12_SURGE_dummy_flx' , -12 , 'sowafldo', .false. , .true. , 'yearly' , '' , '' , ''
/
-
Transform atmospheric pressure into an equivalent inverse barometer sea surface height.
-
Hourly mean sea level pressure is read from daily files generated in Atmospheric Forcing Creation
.
!-----------------------------------------------------------------------
&namsbc_apr ! Atmospheric pressure used as ocean forcing (ln_apr_dyn =T)
!-----------------------------------------------------------------------
rn_pref = 101000. ! reference atmospheric pressure [N/m2]/
nn_ref_apr = 0 ! ref. pressure: 0: constant, 1: global mean or 2: read in a file
ln_apr_obc = .true. ! inverse barometer added to OBC ssh data
cn_dir = './fluxes/' ! root directory for the Patm data location
!___________!_________________________!___________________!___________!_____________!________!___________!__________________!__________!_______________!
! ! file name ! frequency (hours) ! variable ! time interp.! clim ! 'yearly'/ ! weights filename ! rotation ! land/sea mask !
! ! ! (if <0 months) ! name ! (logical) ! (T/F) ! 'monthly' ! ! pairing ! filename !
sn_apr = 'amm12_surge_somslpre' , 1. ,'somslpre' , .true. , .false., 'daily' , '' , '' , ''
/
Tides (&nam_tide)
-
Activate tidal forcing, including tidal potential, on the domain boundaries.
-
Use a linear ramp to introduce the tides over the duration of 1-day.
!-----------------------------------------------------------------------
&nam_tide ! tide parameters (default: OFF)
!-----------------------------------------------------------------------
ln_tide = .true. ! Activate tides
ln_tide_pot = .true. ! use tidal potential forcing
sn_tide_cnames(1) = 'Q1' ! name of constituent
sn_tide_cnames(2) = 'O1'
sn_tide_cnames(3) = 'P1'
sn_tide_cnames(4) = 'S1'
sn_tide_cnames(5) = 'K1'
sn_tide_cnames(6) = '2N2'
sn_tide_cnames(7) = 'MU2'
sn_tide_cnames(8) = 'N2'
sn_tide_cnames(9) = 'NU2'
sn_tide_cnames(10) = 'M2'
sn_tide_cnames(11) = 'L2'
sn_tide_cnames(12) = 'T2'
sn_tide_cnames(13) = 'S2'
sn_tide_cnames(14) = 'K2'
sn_tide_cnames(15) = 'M4'
ln_tide_ramp = .true. ! Use linear ramp for tides at startup
rn_tide_ramp_dt = 1. ! ramp duration in days
/
Unstructured Open Boundaries (&nambdy)
-
Use Flather radiation scheme for the barotropic variables
cn_dyn2d = 'flather'. -
Use tidal harmonic forcing without external tidal data.
-
Use the Flow Relaxation Scheme (FRS) for all variables (
cn_tra,cn_dyn3d) & set bdy data equal to the initial state (nn_tra_dta = 0).
!-----------------------------------------------------------------------
&nambdy ! unstructured open boundaries (default: OFF)
!-----------------------------------------------------------------------
ln_bdy = .true. ! Use unstructured open boundaries
nb_bdy = 1 ! number of open boundary sets
!
cn_dyn2d = 'flather'
nn_dyn2d_dta = 2
cn_tra = 'frs'
nn_tra_dta = 0
cn_dyn3d = 'frs'
/
Bottom Drag (&namdrg)
- Use non-linear bottom friction parameterisation assuming quadratic bottom friction.
!-----------------------------------------------------------------------
&namdrg ! top/bottom drag coefficient (default: NO selection)
!-----------------------------------------------------------------------
! Quadratic
ln_non_lin = .true. ! non-linear drag coefficient
ln_loglayer = .false. ! logarithmic drag: Cd = vkarmn/log(z/z0) |U|
/
Equation Of Seawater (&nameos)
- Use simplified Equation of State for Seawater with reference temperature and salinity consistent with initial conditions.
!-----------------------------------------------------------------------
&nameos ! ocean Equation Of Seawater (default: NO selection)
!-----------------------------------------------------------------------
ln_teos10 = .false. ! = Use TEOS-10 equation of state
ln_seos = .true. ! = Simplified EOS.
rn_T0 = 10. ! reference temperature
rn_S0 = 35. ! reference salinity
/
Tracer Lateral Diffusion (&namtra_ldf)
- Turn off lateral mixing - lateral diffusive tendency will not be applied to the tracer equation.
!-----------------------------------------------------------------------
&namtra_ldf ! lateral diffusion scheme for tracers (default: NO selection)
!-----------------------------------------------------------------------
ln_traldf_OFF = .true. ! No explicit diffusion
ln_traldf_lap = .false. ! laplacian operator
ln_traldf_hor = .true. ! horizontal (geopotential)
! ! Coefficients:
nn_aht_ijk_t = 0 ! = 0 constant = 1/2 Ud*Ld (lap case)
rn_Ud = 0.01 ! lateral diffusive velocity [m/s] (nn_aht_ijk_t= 0, 10, 20, 30)
rn_Ld = 10.e+3 ! lateral diffusive length [m] (nn_aht_ijk_t= 0, 10)
/
Hydrostatic Pressure Gradient (&namdyn_hpg)
- Use standard Jacobian formulation for pressure gradient with a generalised s(x, y, z, t) coordinates.
!-----------------------------------------------------------------------
&namdyn_hpg ! Hydrostatic pressure gradient option (default: NO selection)
!-----------------------------------------------------------------------
ln_hpg_prj = .false. ! s-coordinate (Pressure Jacobian scheme)
ln_hpg_sco = .true. ! s-coordinate (standard jacobian formulation)
/
Vertical Physics (&namzdf)
- Do not compute the vertical eddy viscosity and diffusivity coefficients using the
Generic Length Scale (GLS) scheme
ln_zdfgls = .false..
!-----------------------------------------------------------------------
&namzdf ! vertical physics (default: NO selection)
!-----------------------------------------------------------------------
ln_zdfgls = .false. ! Generic Length Scale closure (T => fill namzdf_gls)
ln_zdfcst = .true. ! constant mixing
! ! coefficients
rn_avm0 = 0.1e-6 ! vertical eddy viscosity [m2/s] (background Kz if ln_zdfcst=F)
rn_avt0 = 0.1e-6 ! vertical eddy diffusivity [m2/s] (background Kz if ln_zdfcst=F)
nn_avb = 0 ! profile for background avt & avm (=1) or not (=0)
nn_havtb = 0 ! horizontal shape for avtb (=1) or not (=0)
/
Success
You have now modified the namelist_cfg file for the case of a 1-layer barotropic model.
Next, continue to the fifth tutorial Running AMM12_SURGE 
to learn how to run a simulation both with and without tidal boundary forcing.