Test of improved boundaries configuration for the Tagus Estuary Pre-operational Model (OM) Ângela...

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)


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


• 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)


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

)


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)


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)


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)


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

)


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)


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

)


Tide appears first in model

Test of improved boundaries configuration for the Tagus Estuary Pre-operational Model (OM) Ângela...

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