unrealistic high temperature near the Changjiang estuary

[zhangjp]

I encountered a problem in the modeling of East China Sea. When active the river source of ChangJiang with M2 tide, there was unrealistic high temperature near the bottom layer (about 3℃ in summer and 1℃ in winter).I've tried several advection and mixing schemes. The modeled temperature sections are showed as follow:

U3HADVECTION + C4VADVECTION LMD


U3HADVECTION + C4VADVECTION GLS(k-kl)


C4HADVECTION + C4VADVECTION GLS(k-kl)

Depth:9m near bottom salinity

Depth:9m near boottom temperature


A4HADVECTION + A4VADVECTION GLS(k-kl)


As the pictures shows,the unrealistic temperature always appears in the greatest salinity gradient region, and the high temperature region seems isolated and I don't know where it comes from. The results from those experiments showed no difference here. Maybe there is something I've missed or not considered probably. Any advice will be appreiated.

The related cpp defination and several parameters are listed below:

cpp.h
# undef TS_SMAGORINSKY
# define TS_DIF2

# define GLS_MIXING
# define CHARNOK /*Charnok Surface Roughness From Wind Stress */
# undef CRAIG_BANNER /*Craig and Banner Wave Breaking Surface Flux */
# define KANTHA_CLAYSON /*Kantha and Clayson stability function */
# undef CANUTO_B /*Canuto B-stability function formulation */
# define N2S2_HORAVG /*Horizontal Smoothing of Buoyancy/Shea */

/* Tides */
# define RAMP_TIDES
# define SSH_TIDES
# define ADD_FSOBC
# define UV_TIDES
# define ADD_M2OBC
# undef FSOBC_REDUCED

/* Point Sources - Rivers */
# define TS_PSOURCE
# define UV_PSOURCE

params.in

VISC2 == 50.0d0 ! m2/s !zhangjp
VISC4 == 0.0d0 ! m4/s
ad_VISC2 == 50.0d0 ! m2/s
ad_VISC4 == 0.0d0 ! m4/s
TNU2 == 750.0d0 750.0d0 ! m2/s
TNU4 == 2*0.0d0 ! m4/s
Lm == 192 ! Number of I-direction INTERIOR RHO-points
Mm == 432 ! Number of J-direction INTERIOR RHO-points
N == 24 ! Number of vertical levels
NTIMES == 1280640 !20yr
DT == 450.0d0
NDTFAST == 18
LtracerSrc == T T ! temperature, salinity, inert

[susonic]

Hi,

Did you give salinity only to the river forcing file or both temperature and salinity?

-Peter

[zhangjp]

Hi,Peter,thanks for your response.
Both temperature and salinity are given to the river forcing file in my model.

[susonic]

I had faced with similar situation before. I gave only salinity at that time.
It was solved with both temperature and salinity on with my river forcing.

See this disscussion,
viewtopic.php?f=31&t=867&hilit=susonic

Now I don't have a good solution but I doubt whether you put river source in a right grid point.

And does the negative temperature appear all the time? When does it appear?

-Peter

[zhangjp]

Hi,Peter. Thanks for your reply. I've read your post.

It was solved with both temperature and salinity on with my river forcing.

I had faced with similar situation as yours when I gave only salinity before. Then I added both temperature and salinity.

I doubt whether you put river source in a right grid point.

I put my river source on one grid point at the upriver grid(near 120E\30.8N, see the pic above).
I think the temperature and salinity that given to the river point is ok. Near the upriver grid, the temperature and salinity is close to the value I gave to them, which can see from the pic above as well.

And does the negative temperature appear all the time? When does it appear?

The unrealistic high temperature appears all the time and more obviouse when river discharge is larger in the wet season.

The high temperature region mostly located near the mouth of the estuary, more accurately it located at the salinity front and shifted with the the strength of the discharge. Is there any relationship between the high temperature and the gradient of the salinity or the mixing process?

[zhangjp]

Hi, everyone!

I changed the vertical turbulent mixing scheme from gls(k-kl) to MY25, the problem is still existing.

MY25 with U3HADVECTION + C4VADVECTION


The temperature is high on the bottom layer and it is low in the upper layer.


Here's my parameters:
7.5000E+02 nl_tnu2(01) NLM Horizontal, harmonic mixing coefficient
(m2/s) for tracer 01: temp
7.5000E+02 nl_tnu2(02) NLM Horizontal, harmonic mixing coefficient
(m2/s) for tracer 02: salt
5.0000E+01 nl_visc2 NLM Horizontal, harmonic mixing coefficient
(m2/s) for momentum.
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).
1.5000E-03 rdrg2 Quadratic bottom drag coefficient.
1.0000E-03 Zob Bottom roughness (m).
1 lmd_Jwt Jerlov water type.
1 Vtransform S-coordinate transformation equation.
1 Vstretching S-coordinate stretching function.
4.0000E+00 theta_s S-coordinate surface control parameter.
4.0000E-01 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.
0.000 dstart Time-stamp assigned to model initialization (days).
0.000 tide_start Reference time origin for tidal forcing (days).
20000101.00 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.
14.000 T0 Background potential temperature (C) constant.
35.000 S0 Background salinity (PSU) constant.
1.000 gamma2 Slipperiness variable: free-slip (1.0) or
no-slip (-1.0).

Activated C-preprocessing Options:
ADD_FSOBC Adding tidal elevation to proccesed OBC data.
ADD_M2OBC Adding tidal currents to proccesed OBC data.
ANA_BSFLUX Analytical kinematic bottom salinity flux.
ANA_BTFLUX Analytical kinematic bottom temperature flux.
ASSUMED_SHAPE Using assumed-shape arrays.
AVERAGES Writing out time-averaged fields.
CURVGRID Orthogonal curvilinear grid.
DIFF_GRID Horizontal diffusion coefficient scaled by grid size.
DJ_GRADPS Parabolic Splines density Jacobian (Shchepetkin, 2002).
DOUBLE_PRECISION Double precision arithmetic.
EAST_FSCHAPMAN Eastern edge, free-surface, Chapman condition.
EAST_M2FLATHER Eastern edge, 2D momentum, Flather condition.
EAST_M3NUDGING Eastern edge, 3D momentum, passive/active outflow/inflow.
EAST_M3RADIATION Eastern edge, 3D momentum, radiation condition.
EAST_TNUDGING Eastern edge, tracers, passive/active outflow/inflow.
EAST_TRADIATION Eastern edge, tracers, radiation condition.
EAST_VOLCONS Eastern edge, enforce mass conservation.
MASKING Land/Sea masking.
MIX_GEO_TS Mixing of tracers along geopotential surfaces.
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.
POWER_LAW Power-law shape time-averaging barotropic filter.
PROFILE Time profiling activated .
QCORRECTION Surface net heat flux correction.
K_GSCHEME Third-order upstream advection of TKE fields.
RAMP_TIDES Ramping tidal forcing for one day.
!RST_SINGLE Double precision fields in restart NetCDF file.
SALINITY Using salinity.
SCORRECTION Surface salinity flux correction.
SOLAR_SOURCE Solar Radiation Source Term.
SOLVE3D Solving 3D Primitive Equations.
SOUTH_FSCHAPMAN Southern edge, free-surface, Chapman condition.
SOUTH_M2FLATHER Southern edge, 2D momentum, Flather condition.
SOUTH_M3NUDGING Southern edge, 3D momentum, passive/active outflow/inflow.
SOUTH_M3RADIATION Southern edge, 3D momentum, radiation condition.
SOUTH_TNUDGING Southern edge, tracers, passive/active outflow/inflow.
SOUTH_TRADIATION Southern edge, tracers, radiation condition.
SOUTH_VOLCONS Southern edge, enforce mass conservation.
SPHERICAL Spherical grid configuration.
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.
TS_DIF2 Harmonic mixing of tracers.
TS_PSOURCE Tracers point sources and sinks.
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_LOGDRAG Logarithmic bottom stress.
UV_PSOURCE Mass point sources and sinks.
UV_TIDES Add tidal currents to 2D momentum climatologies.
UV_VIS2 Harmonic mixing of momentum.
VAR_RHO_2D Variable density barotropic mode.
VISC_3DCOEF Horizontal, time-dependent 3D viscosity coefficient.

[kate]

Maybe you can try turning on TS_DIAGNOSTICS and figure it out from that.

[feroda]

I am wondering if anyone has updates to this issue, since I am in the similar issue for quite a while. The temperature as well as salinity are abnormally high in my river channels. I didn't pay much attention to this issue, because the rivers are neglectable in my basin-scale analysis.