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Test of improved boundaries configuration for the Tagus Estuary Pre-operational Model (OM)
Ângela Canas
MaretecSANESTSANEST
Objective What was known:• Studies show needed improvement
of boundary conditions: large, surface, rivers, bathymetry (e.g. R.
Fernandes, 2005)• Version 4 of MOHID allows
advanced advection
Assess effect in 3D Level 2 results of all possible
improvements of boundaries and advection now possible
Continental Portuguese Coast
Continental Portuguese CoastLevel 1
Level 2
New bathymetryNew bathymetry
MM5 HDF5 forcingMM5 HDF5 forcing
Advection TVD - SuperbeeAdvection TVD - Superbee
Sorraia hourly flow
Sorraia hourly flow
Relaxation to Levitus monthly profile climatology (T, S)
Relaxation to Levitus monthly profile climatology (T, S)
Common in literature
Changes:Level 1: Portuguese Coast, resolution 24km, TVD - Superbee, BIHARMONIC_COEF : 1e9, HDF5 MM5 forcing (best resolution) Level 2: 3D (33 layers), BAROCLINIC_METHOD : 3, BAROCLINIC_POLIDEGREE : 1, TVD - Superbee, relax. to 1 T/S Levitus profile in all boundary, HDF5 MM5 forcing (best resolution)
Methodology
Simulation 1 (S1)
Current configuration but Version 4
Simulation 2 (S2)
Improved configuration (Version 4)
To support internal tide ConvertToHDF5 action Patch HDF5 Files
Background:Level 1: S. Vicente Leixões, 2D, resolution 2 km, barotrophic, upwind, BIHARMONIC_COEF : 1e8, time serie MM5 forcing, tide, t = 60sLevel 2: 3D (11 layers), resolution 0.32km, baroclinic, BAROCLINIC_METHOD : 1, upwind, 36 psu relax. b.c., hydro Flather radiation b.c., time serie MM5 forcing, t = 15s, Tagus – Sorraia – Trancão river flows, GOTM
Methodology
Initialization:• Slowstart, wind smooth period (1 day)• Level 2: water level = 2.08m, baroclinic ramp 1 inertial period (S2) • Temperature: constant 16ºC (S1), Levitus (S2)• Salinity: estuary boxes, sea constant 36 psu (S1) or Levitus (S2)• Density: constant 1026.73 g/m3 (S1), variable in depth for pressure (S2)
Assessment (01/02/2005 01/03/2005): • Predicted tide gauge water level (TidePrev)• SST (MODIS)• CTD (SANEST)
15/01/2005, 0h 01/03/2005, 0h
S1 S2
After 08/02/2005, 6h: b.c. for T/S = null gradient for dephts < 100m bigger concurrence with MODIS SST
Results: hydrodynamic
Velocity modulus (m/s)
S1
Velocity modulus (m/s)
S2
Surface values
Internal tide: • Associated with vertical oscilations of isotherms due to interaction between tide and continental shelf slope• Not visible in the water level (change only a few cm)
Maximum velocity points in Nazare canyon according with known internal tide (H. Coelho, C. Garcia)
Results: hydrodynamic
0
0.1
0.2
0.3
0.4
0.5
Penich
e
Casca
is
Paço
de A
rcos
Lisb
oa
Povoa
de S
anta
Iria
VilaFra
nca
Ponta
da
Erva
Alcoch
ete
Cabo
Ruivo
Mon
tijo
Alfeite
Seixa
l
Cacilh
as
Trafa
ria
Sesim
bra
Location
RM
SE
(m
)
TP-S1 TP-S2 new TP-S1 tide TP-S2 new tide
0.95
0.96
0.97
0.98
0.99
1
Penich
e
Casca
is
Paço
de A
rcos
Lisb
oa
Povoa
de S
anta
Iria
VilaFra
nca
Ponta
da
Erva
Alcoch
ete
Cabo
Ruivo
Mon
tijo
Alfeite
Seixa
l
Cacilh
as
Trafa
ria
Sesim
bra
Location
Co
rrel
atio
n c
oef
fici
ent
TP-S2 new TP-S2 new tide TP-S1 TP-S1 tide
• Greater improvement inside estuary• Still, better results outside estuary
higher resolution
better bathymetry
Results: hydrodynamic
• Significant phase differences do not occur• Mean level generally smaller in model
Cascais
0
1
2
3
4
5
28-2-050:00
28-2-054:48
28-2-059:36
28-2-0514:24
28-2-0519:12
1-3-05 0:00
Time
Wat
er l
evel
(m
)
Simulation 1 TidePrev Simulation 2 new boundary
Vila Franca
0
1
2
3
4
5
28-2-05 0:00 28-2-05 6:00 28-2-0512:00
28-2-0518:00
1-3-05 0:00
Time
Wa
ter
lev
el
(m)
Simulation 1 TidePrev Simulation 2 new boundary
Study of the effect of pressure in water level (to be released)evidences que existence of a systematic error in mean level used for tide forcing (2.08m) causes degradation of RMSE
Water level in channel areas still poorly
representedImprove
grid resolution
Results: SST
Improvements: • more realistic spatial variability• acceptable results in the Outfall in upwelling events
Results: SST
Remaining problems: • off-coast poor results• systematic general cooling• null gradient b. c. not adequate
• boundaries too close to interest area• excessive internal tide causes too much mixture (low sensitivity to meteo)
systematic cooling
Results: vertical stratification, temperature and salinity
Location G08
13
13.5
14
14.5
15
15.5
35.3 35.4 35.5 35.6 35.7 35.8 35.9
Salinity (psu)
Tem
per
atu
re (
ºC)
CTD (14h30) Simulation 1 (15h) Simulation 2 (15h)
Location G16
13.5
14
14.5
15
15.5
35.4 35.5 35.6 35.7 35.8 35.9 36
Salinity (psu)
Te
mp
era
ture
(ºC
)
CTD (12h49) Simulation 1 (13h) Simulation 2 (13h)
Overestimation of T and underestimation of S greatly reduced
Measurement date: 01/02/05
Guia Outfall near location G08
Depths: 2.55m, 7.5m, 15m and 27.5m
Location G08
-5
5
15
25
35
45
13 13.5 14 14.5 15 15.5
Temperature (ºC)
Dep
th (
m)
CTD (14h30) Simulation 1 (15h) Simulation 2 (15h)
Location G08
-5
5
15
25
35
45
35.3 35.4 35.5 35.6 35.7 35.8 35.9 36
Salinity (psu)
Dep
th (
m)
CTD (14h30) Simulation 1 (15h) Simulation 2 (15h)
Results: vertical stratification, temperature and salinity
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
G01
G05
G06
G08
G10
G12
G14
G15
G16
G17
GM
ET
CTD location
RM
SE
(T
emp
. ºC
, S
alin
. p
su)
Temp. S1-CTD
Temp. S2-CTD
Salin. S1-CTD
Salin.S2-CTD
Stratification still poorly capturedError in salinity and temperature
non concurrent
Location G05
-5
0
5
10
15
20
25
30
34.8 35 35.2 35.4 35.6 35.8 36
Salinity (psu)
Dep
th (
m)
CTD (15h36) Simulation 1 (16h) Simulation 2 (16h)
Location G05
-5
0
5
10
15
20
25
30
13.2 13.4 13.6 13.8 14 14.2 14.4 14.6 14.8 15
Temperature (ºC)
De
pth
(m
)
CTD (15h36) Simulation 1 (16h) Simulation 2 (16h)
Poor vertical discretization
?
CTD and field data should be
found and analysed for
off-coast (Coriolis) and inside estuary
Results: kinetic and potential energy
0.00E+00
1.00E-03
2.00E-03
3.00E-03
4.00E-03
5.00E-03
6.00E-03
16-1-05 26-1-05 5-2-05 15-2-05 25-2-05
Time
Kin
etic
en
erg
y p
er m
ass
Simulation 1 Simulation 2 (33 layers)
-4.00E-01
-3.50E-01-3.00E-01
-2.50E-01-2.00E-01
-1.50E-01-1.00E-01
-5.00E-020.00E+00
16-1-05 26-1-05 5-2-05 15-2-05 25-2-05
Time
Po
ten
tial
en
erg
y p
er m
ass
Simulation 2 (33 layers) Simulation 1
Higher initial energy effect of internal tide
Decrease of potential energy
water too hot induces sinking
Still observed in Simulation 2
-2.00E-01
-1.50E-01
-1.00E-01
-5.00E-02
0.00E+00
11-2-05
0:00
11-2-05
12:00
12-2-05
0:00
12-2-05
12:00
13-2-05
0:00
13-2-05
12:00
14-2-05
0:00
14-2-05
12:00
15-2-05
0:00
TimeP
ote
nti
al e
ner
gy
per
mas
s
Simulation 2 (33 layers) Simulation 1
Different tide print on potential
energy ?
Conclusions
New configuration provides improved results for: Water level: especially inside the Tagus estuary
effect of new bathymetry; Temperature/salinity: especially in the Guia Outfall
area effect of improved stratification;
Unsolved problems: Water level in channels near river locations; SST away from coast.
Conclusions Detected incorrections:
Time serie for atmospheric forcing of current configuration not represent surface values (average of first MM5 layer):
6
8
10
12
14
16
15-01-2005
20-01-2005
25-01-2005
30-01-2005
04-02-2005
09-02-2005
14-02-2005
19-02-2005
24-02-2005
01-03-2005
Time
Tem
per
atu
re (
º C
)
MM5 Time Serie MM5 Domain 3 Time Serie
-12
-9
-6
-3
0
3
6
9
15-01-2005
20-01-2005
25-01-2005
30-01-2005
04-02-2005
09-02-2005
14-02-2005
19-02-2005
24-02-2005
01-03-2005
Time
Ve
loc
ity
So
uth
-No
rth
(m
/s)
MM5 Time Serie MM5 Domain 3 Time Serie
Explains in part disparities found by R. Fernandes (2005)
Conclusions
Detected incorrections: Tide component files for Montijo, Seixal and
Alcochete with incorrect time reference (less 1h) Montijo
0
1
2
3
4
5
28-2-05 0:00 28-2-05 6:00 28-2-0512:00
28-2-0518:00
1-3-05 0:00
Time
Wa
ter
lev
el
(m)
Simulation 1 TidePrev Simulation 2 new boundary
Montijo Seixal Alcochete Ponta da Erva
Póvoa de Santa Iria
Vila Franca
N2 Amp. TP 0.2525 0.2420 0.2521 0.2642 0.2502 0.2266 Amp. S2 0.2727 0.2676 0.2695 0.2087 0.2165 0.1687 Phase TP 90.28 90.86 97.94 101.61 103.89 121.18 Phase S2 58.17 59.48 67.68 80.97 79.06 98.7 Phase difference 32.11 31.38 30.26 20.64 24.83 22.48 Phase difference (+ 1h) 3.67 2.94 1.82 -7.80 -3.61 -5.96 M2 Amp. TP 1.2011 1.1591 1.2672 1.2978 1.2619 1.1962 Amp. S2 1.2065 1.1886 1.2321 1.0553 1.0578 0.8530 Phase TP 106.77 107.36 112.10 115.65 117.48 132.47 Phase S2 82.09 83.04 91.33 108.05 103.92 125.54 Phase difference 24.68 24.32 20.77 7.60 13.56 6.93 Phase difference (+ 1h) -4.31 -4.67 -8.22 -21.39 -15.43 -22.06 S2 Amp. TP 0.4225 0.4082 0.4356 0.4469 0.4226 0.3711 Amp. S2 0.5018 0.4921 0.5052 0.3853 0.4058 0.3080 Phase TP 137.30 137.68 144.99 148.84 150.63 169.79 Phase S2 129.80 131.08 141.98 162.35 156.85 179.74 Phase difference 7.50 6.60 3.01 -13.51 -6.22 -9.95 Phase difference (+ 1h) -22.50 -23.40 -26.99 -43.51 -36.22 -39.95
Alcochete
0
1
2
3
4
5
28-2-05 0:00 28-2-05 6:00 28-2-05 12:00 28-2-05 18:00 1-3-05 0:00
Time
Wat
er l
evel
(m
)
Simulation 1 TidePrev Simulation 2 new boundary
Tide appears first in model