Radiation temporal resolution and overheating problem.

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LeaF_7
Posts: 21
Joined: Tue Aug 12, 2014 8:32 pm
Location: Institute of Marine Research

Radiation temporal resolution and overheating problem.

#1 Unread post by LeaF_7 »

Hi,

I am implementing a high resolution model(1km horizontally) with 40 vertical levels in the Yellowsea and Bohai sea. The model was developed by somebody else in the beginning and I am trying to optimize and validate the model. As I am kind of new to ocean modelling, so I need to seek advice on the problems I've encountered.

The model was running on a rotated grid, we have one open boundary on the east side. The initial and boundary conditions was interpolated from HYCOM analysis 1/12 degree global model. And the model was forced with the tidal forcing from TPXO7.2 on the open boundary. We use BULK_FLUXES with atmospheric forcing from ERA-interim. The solar and thermal radiation was computed from the 12 hour accumulated values, which we only use the 12 and 00 value in the heat flux for ROMS to do the interpolation. The vertical mixing scheme was Mellor-Yamada 2.5 in the model run.

By compare with the HYCOM file and our measurement, the model was overheated a lot in summer near the coast. And also the vertical temperature profile was not realistic compare to our observation.
The comparison of the surface temperature is shown in the figure below.
YSM_surface.png
YSM_surface.png (76.73 KiB) Viewed 2975 times
HYCOM_surface.png
HYCOM_surface.png (52.59 KiB) Viewed 2975 times
We also have some CTD measurement near the coast and the stations and result for station 1 and station 9 was shown below as well. the coastal water is being overheated a lot and there seem to be too much vertical mixing.
CTD stations.jpg
CTD stations.jpg (59.58 KiB) Viewed 2972 times
T_profile_s1.png
T_profile_s1.png (5.93 KiB) Viewed 2972 times
T_profile_s9.png
T_profile_s9.png (6.41 KiB) Viewed 2972 times
I wonder whether the low resolution of the radiations would be a reason why the coastal water is being overheated. If we use the 3-hourly forcast value there would be some improvement?
Our measurement was taken in July, and the region should be in the tidal mixing front in the Yellowsea, it seemed that the model did not perform very well in this region with the MY2.5 scheme. Are there any suggestions or experience for setup models in similar places?
Thanks very much for your patient and time for looking at this long post.
Some of the log files are attached below.

Code: Select all

Yellow Sea

 Operating system : Linux
 CPU/hardware     : x86_64
 Compiler system  : ftn
 Compiler command : /opt/cray/craype/2.4.2/bin/ftn
 Compiler flags   :  -O3 -free

 Input Script  : 

 SVN Root URL  : https:://myroms.org/svn/src
 SVN Revision  : exported

 Local Root    : /work/users/fanlin/roms_kate_ser
 Header Dir    : /work/fanlin/roms_kate_ser/Apps/Arctic
 Header file   : yellowsea.h
 Analytical Dir: /work/fanlin/roms_kate_ser/Apps/Arctic

 Resolution, Grid 01: 0824x0785x040,  Parallel Nodes: 256,  Tiling: 016x016


 Physical Parameters, Grid: 01
 =============================

     172800  ntimes            Number of timesteps for 3-D equations.
     60.000  dt                Timestep size (s) for 3-D equations.
         10  ndtfast           Number of timesteps for 2-D equations between
                                 each 3D timestep.
          1  ERstr             Starting ensemble/perturbation run number.
          1  ERend             Ending ensemble/perturbation run number.
         -1  nrrec             Number of restart records to read from disk.
          T  LcycleRST         Switch to recycle time-records in restart file.
       1440  nRST              Number of timesteps between the writing of data
                                 into restart fields.
          1  ninfo             Number of timesteps between print of information
                                 to standard output.
          T  ldefout           Switch to create a new output NetCDF file(s).
        240  nHIS              Number of timesteps between the writing fields
                                 into history file.
       1440  ndefHIS           Number of timesteps between creation of new
                                 history files.
          1  ntsAVG            Starting timestep for the accumulation of output
                                 time-averaged data.
       2880  nAVG              Number of timesteps between the writing of
                                 time-averaged data into averages file.
       2880  ndefAVG           Number of timesteps between creation of new
                                 time-averaged file.
 1.0000E+01  nl_visc2          NLM Horizontal, harmonic mixing coefficient
                                 (m2/s) for momentum.
          F  LuvSponge         Turning OFF sponge on horizontal momentum.
          F  LtracerSponge(01) Turning OFF sponge on tracer 01: temp
          F  LtracerSponge(02) Turning OFF sponge on tracer 02: salt
 1.0000E-06  Akt_bak(01)       Background vertical mixing coefficient (m2/s)
                                 for tracer 01: temp
 1.0000E-06  Akt_bak(02)       Background vertical mixing coefficient (m2/s)
                                 for tracer 02: salt
 1.0000E-05  Akv_bak           Background vertical mixing coefficient (m2/s)
                                 for momentum.
 5.0000E-06  Akk_bak           Background vertical mixing coefficient (m2/s)
                                 for turbulent energy.
 5.0000E-06  Akp_bak           Background vertical mixing coefficient (m2/s)
                                 for turbulent generic statistical field.
 3.0000E-04  rdrg              Linear bottom drag coefficient (m/s).
 2.0000E-03  rdrg2             Quadratic bottom drag coefficient.
 2.0000E-02  Zob               Bottom roughness (m).
 2.0000E+00  blk_ZQ            Height (m) of surface air humidity measurement.
 2.0000E+00  blk_ZT            Height (m) of surface air temperature measurement.
 1.0000E+01  blk_ZW            Height (m) of surface winds measurement.
          1  lmd_Jwt           Jerlov water type.
          2  Vtransform        S-coordinate transformation equation.
          4  Vstretching       S-coordinate stretching function.
 7.0000E+00  theta_s           S-coordinate surface control parameter.
 2.0000E+00  theta_b           S-coordinate bottom  control parameter.
     10.000  Tcline            S-coordinate surface/bottom layer width (m) used
                                 in vertical coordinate stretching.
   1025.000  rho0              Mean density (kg/m3) for Boussinesq approximation.
  42124.000  dstart            Time-stamp assigned to model initialization (days).
  41273.000  tide_start        Reference time origin for tidal forcing (days).
19000101.00  time_ref          Reference time for units attribute (yyyymmdd.dd)
 3.6000E+02  Tnudg(01)         Nudging/relaxation time scale (days)
                                 for tracer 01: temp
 3.6000E+02  Tnudg(02)         Nudging/relaxation time scale (days)
                                 for tracer 02: salt
 3.6000E+02  Znudg             Nudging/relaxation time scale (days)
                                 for free-surface.
 3.6000E+02  M2nudg            Nudging/relaxation time scale (days)
                                 for 2D momentum.
 3.6000E+02  M3nudg            Nudging/relaxation time scale (days)
                                 for 3D momentum.
 1.2000E+02  obcfac            Factor between passive and active
                                 open boundary conditions.

 Lateral Boundary Conditions: NLM
 ============================

 Variable               Grid  West Edge    South Edge   East Edge    North Edge
 ---------              ----  ----------   ----------   ----------   ----------

 zeta                     1   Closed       Closed       Chapman Imp  Closed

 ubar                     1   Closed       Closed       Shchepetkin  Closed

 vbar                     1   Closed       Closed       Shchepetkin  Closed

 u                        1   Closed       Closed       Rad + Nud    Closed

 v                        1   Closed       Closed       Rad + Nud    Closed

 temp                     1   Closed       Closed       Rad + Nud    Closed

 salt                     1   Closed       Closed       Rad + Nud    Closed

 tke                      1   Closed       Closed       Closed       Closed

 uice                     1   Closed       Closed       Gradient     Closed

 vice                     1   Closed       Closed       Gradient     Closed

 aice                     1   Closed       Closed       Mixed        Closed

 hice                     1   Closed       Closed       Mixed        Closed

 tisrf                    1   Closed       Closed       Mixed        Closed

 snow_thick               1   Closed       Closed       Mixed        Closed

 sfwat                    1   Closed       Closed       Mixed        Closed


Activated C-preprocessing Options:

 YELLOWSEA           Yellow Sea
 ADD_FSOBC           Adding tidal elevation to processed OBC data.
 ADD_M2OBC           Adding tidal currents to processed OBC data.
 ALBEDO_CURVE        Shortwave radiation adjusted by albedo curve.
 ANA_BSFLUX          Analytical kinematic bottom salinity flux.
 ANA_BTFLUX          Analytical kinematic bottom temperature flux.
 ANA_NUDGCOEF        Analytical spatially varying nudging time-scales.
 ASSUMED_SHAPE       Using assumed-shape arrays.
 AVERAGES            Writing out time-averaged nonlinear model fields.
 BULK_FLUXES         Surface bulk fluxes parameterization.
 CORE_FORCING        Humidity from CORE forcing files.
 CURVGRID            Orthogonal curvilinear grid.
 DJ_GRADPS           Parabolic Splines density Jacobian (Shchepetkin, 2002).
 DOUBLE_PRECISION    Double precision arithmetic.
 EMINUSP             Compute Salt Flux using E-P.
 ICE_ADVECT          Advection of ice tracers.
 ICE_ALB_EC92        Ebert and Curry albedo formula.
 ICE_BULK_FLUXES     Ice bulk fluxes from the atmosphere.
 ICE_EVP             Elastic-viscous-plastic ice rheology.
 ICE_MK              Mellor-Kantha ice thermodynamics.
 ICE_MODEL           Include sea ice model.
 ICE_MOMENTUM        Compute ice momentum equations.
 ICE_SMOLAR          Advect ice tracers with MPDATA scheme.
 ICE_THERMO          Include ice thermodynamics.
 LIMIT_BSTRESS       Limit bottom stress to maintain bottom velocity direction.
 KANTHA_CLAYSON      Kantha and Clayson stability function formulation.
 LONGWAVE_OUT        Compute outgoing longwave radiation internally.
 MASKING             Land/Sea masking.
 MIX_S_UV            Mixing of momentum along constant S-surfaces.
 MPI                 MPI distributed-memory configuration.
 MY25_MIXING         Mellor/Yamada Level-2.5 mixing closure.
 NONLINEAR           Nonlinear Model.
 NONLIN_EOS          Nonlinear Equation of State for seawater.
 NO_SCORRECTION_ICE  Not including SCORRECTION under the ice.
 NO_WRITE_GRID       Not Writing grid arrays into NetCDF ouput files.
 N2S2_HORAVG         Horizontal smoothing of buoyancy and shear.
 POWER_LAW           Power-law shape time-averaging barotropic filter.
 PROFILE             Time profiling activated .
 K_GSCHEME           Third-order upstream advection of TKE fields.
 RADIATION_2D        Use tangential phase speed in radiation conditions.
 RAMP_TIDES          Ramping tidal forcing for one day.
 RST_SINGLE          Single precision fields in restart NetCDF file.
 SALINITY            Using salinity.
 SOLAR_SOURCE        Solar Radiation Source Term.
 SOLVE3D             Solving 3D Primitive Equations.
 SPLINES             Conservative parabolic spline reconstruction.
 SSH_TIDES           Add tidal elevation to SSH climatology.
 TS_U3HADVECTION     Third-order upstream horizontal advection of tracers.
 TS_C4VADVECTION     Fourth-order centered vertical advection of tracers.
 UV_ADV              Advection of momentum.
 UV_COR              Coriolis term.
 UV_U3HADVECTION     Third-order upstream horizontal advection of 3D momentum.
 UV_C4VADVECTION     Fourth-order centered vertical advection of momentum.
 UV_QDRAG            Quadratic bottom stress.
 UV_TIDES            Add tidal currents to 2D momentum climatologies.
 UV_VIS2             Harmonic mixing of momentum.
 UV_SMAGORINSKY      Smagorinksy-like time-dependent viscosity coefficients.
 VAR_RHO_2D          Variable density barotropic mode.
 VISC_3DCOEF         Horizontal, time-dependent 3D viscosity coefficient.

User avatar
wilkin
Posts: 922
Joined: Mon Apr 28, 2003 5:44 pm
Location: Rutgers University
Contact:

Re: Radiation temporal resolution and overheating problem.

#2 Unread post by wilkin »

The solar and thermal radiation was computed from the 12 hour accumulated values, which we only use the 12 and 00 value in the heat flux for ROMS to do the interpolation. The vertical mixing scheme was Mellor-Yamada 2.5 in the model run.
Be careful working with "accumulated" values in that data set. They are an integral over time. Plot some time series and make sure you don't have a sawtooth pattern between the 0000 and 1200 values.

Also, if you use solar radiation sampled only two hours per day you are going to alias the diurnal cycle. You might be better off getting the best daily average you can, and then #define DIURNAL_SRFLUX to introduce the local solar angle into the time variation.
John Wilkin: DMCS Rutgers University
71 Dudley Rd, New Brunswick, NJ 08901-8521, USA. ph: 609-630-0559 jwilkin@rutgers.edu

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