Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin...

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Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia University Palisades, NY
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Page 1: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Vertical Mixing Parameterizations

and their effects on the skill of

Baroclinic Tidal Modeling

 

 Robin Robertson

Lamont-Doherty Earth Observatory

of Columbia University

Palisades, NY

Page 2: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Domain

-128.2 -128.0 -127.8 -127.6 -127.4

Longitude

32.0

32.2

32.4

32.6

32.8

Lat

itu

de

500

1000

1500

2000

2500

3000

3500

4000

W ater Depth

(m)

x = 2 km y =2 km 60 levels

taken from Smith and Sandwell [1997]

B2

B3

F2

F3F4,F5 C

R3

R2 P

Page 3: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Internal Wave Theory

• Internal wave generation criteria according to linear theory

- slope of internal wave rays =1 – critical

– Most generation – resonant

< 1 – subcritical– Less generation– Propagates both on and offslope

> 1 – supercritical– Less generation– Propagates offslope

H

y

122 2

2 2

f

N

Page 4: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Internal Tide Generation according to linear theory

-128.2 -128.0 -127.8 -127.6 -127.4 -127.2

Longitude

32.0

32.2

32.4

32.6

32.8

33.0

La

titu

de

M2

-128.2 -128.0 -127.8 -127.6 -127.4 -127.2

Longitude

32.0

32.2

32.4

32.6

32.8

33.0S

2

-128.2 -128.0 -127.8 -127.6 -127.4 -127.2

Longitude

27.0

27.2

27.4

27.6

27.8

28.0

Lat

itu

de

-128.2 -128.0 -127.8 -127.6 -127.4 -127.2

Longitude

27.0

27.2

27.4

27.6

27.8

28.0K

1O

1

Red indicates expected internal tide generation

Page 5: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

M2 Baroclinic Tides

-4000

-2000

0

Dep

th (

m)

0.5

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

Bottom

-4000

-2000

0

Dep

th (

m)

(cm s -1 )

-4000

-2000

0

Dep

th (

m)

-4000

-2000

0

Dep

th (

m)

32.0 32.2 32.4 32.6 32.8Latitude

-4000

-2000

0

Dep

th (

m)

128o 1.7' W

127o 51.4'W

127o 41.0' W

127o 30.7'W

127o 20.4'W

Base Case (1)

Page 6: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

K1 Baroclinic Tides

-4000

-2000

0

De

pth

(m

)

0.5

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

Bottom

-4000

-2000

0

De

pth

(m

)

(cm s -1 )

-4000

-2000

0

De

pth

(m

)

-4000

-2000

0

De

pth

(m

)

32.0 32.2 32.4 32.6 32.8Latitude

-4000

-2000

0

De

pth

(m

)

128o 1.7' W

127o 51.4'W

127o 41.0' W

127o 30.7'W

127o 20.4'W

Base Case (1)

Page 7: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Comparison to Observations:

M2 Major Axes Observations Model Results

32 42.05 N128 2.70 W

32 28.64 N127 50.44 W

32 28.27 N127 48.57 W

32 26.56 N127 46.16 W

32 9.30 N128 0.49 W

32 25.75N127 50 W

32 24.61 N127 47.57 W

Major Axis (cm s -1 )

M2

B2 F2 R2 C

B3 F3 R3

0 4 8

0

500

1000

1500

2000

2500

3000

3500

4000

4500

De

pth

(m

)

0 4 8 120 4 8 0 4 8 12

0 4 8

0

500

1000

1500

2000

2500

3000

3500

4000

4500

De

pth

(m

)

0 4 8 0 4 8 120 4 8 12

P 32 26.56 N127 46.70 W

Page 8: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Comparison to Observations:K1 Major Axes

Observations Model Results

32 42.05 N128 2.70 W

32 28.64 N127 50.44 W

32 28.27 N127 48.57 W

32 26.56 N127 46.16 W

32 9.30 N128 0.49 W

32 25.75N127 50 W

32 24.61 N127 47.57 W

Major Axis (cm s -1 )

K1

B2 F2 R2 C

B3 F3 R3

0 4 8 12

0

500

1000

1500

2000

2500

3000

3500

4000

4500

De

pth

(m

)

0 4 8 12 160 4 0 4 8 12 16 20

0 4

0

500

1000

1500

2000

2500

3000

3500

4000

4500

De

pth

(m

)

0 4 8 12 0 4 8 12 160 4 8 12

P 32 26.56 N127 46.70 W

Page 9: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Comparison to Observations:Mean Currents

Observations Model Results

32 42.05 N128 2.70 W

32 28.64 N127 50.44 W

32 28.27 N127 48.57 W

32 26.56 N127 46.16 W

32 9.30 N128 0.49 W

32 25.75N127 50 W

32 24.61 N127 47.57 W

Major Axis (cm s -1 )

B2 F2 R2 C

B3 F3,F4,F5

R3

0 4 8 12 16

0

500

1000

1500

2000

2500

3000

3500

4000

4500

De

pth

(m

)

0 4 8 12 16 200 4 0 4 8 12 16 20

0 4

0

500

1000

1500

2000

2500

3000

3500

4000

4500

De

pth

(m

)

0 4 8 120 4 8 12 16 0 4 8 12 16

P 32 26.56 N127 46.70 W

Page 10: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Vertical Mixing Parameterizations

• Large-McWilliams-Doney (LMD) Kp profile

• Mellor-Yamada 2.5 level turbulence closure (MY2.5)

• Brunt-Väisälä frequency (BVF)• Pacanowski-Philander (PP)• Generic Length Scale (GLS)

• Lamont Ocean Atmosphere Mixed Layer Model (LOAM )

• LMD - modified

Page 11: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Large-McWilliams-Doney Kp profile

• Primary processes– Local Ri instabilities due to resolvable

vertical shear• If (1-Ri/0.7) > 0

10-3 (1-Ri/0.7)3

– Convection• N dependent 0.1 * [1.-(2x10-5 –N2)/2x10-5]

– Internal wave • N dependent 10-6/N2 (min N of 10-7)

– Double diffusion• Only for tracers

• For Ri < 0.8, the first dominates• For Ri > 0.8, the third dominates• Modified

– Non-local fluxes, Langmuir, Stokes drift

– Changes two of the Kp profile values

Page 12: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Mellor-Yamada 2.5 level turbulence closure

• Designed for boundary layer flows

• Based on turbulent kinetic energy and length scale which are time stepped through the simulation

• Matched laboratory turbulence• Logarithmic law of the wall• Not designed for internal wave

mixing• Fails in the presence of

stratification

Page 13: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Brunt-Väisälä frequency

• Diffusivity is a function of N– If N < 0 Kv = 1– If N = 0 Kv = background value– If N > 0 Kv = 10-7/N

• Min of 3x10-5

• Max of 4x10-4

– Background values is input (10-6)

Page 14: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Pacanowski-Philander

• Designed for the tropics• Gradient Ri dependent

– If Ri > .2 Kv = 0.01/(1-5Ri)2+background

max = 0.01– Otherwise Kv = 0.01

• LOAM – version modified for use outside the tropics– If Ri > .2 Kv = 0.05/(1-5Ri)2+background

max = 0.05– Otherwise Kv = background

Page 15: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Generic Length Scale

• Two generic equations

– D - turbulent and viscous transport

– P - KE production by shear

– G - KE production by buoyancy - Dissipation

– c - model constants

• Based on turbulent kinetic energy and length scale which are time stepped through the simulation

• MY2.5 is a special case – p=0, m=1, n=1

cGcPc

kDut xi

i 231

nmp

kc0

Page 16: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Major Axis Errors

Vertical Mixing Parameterization

M2 (cm s-1)

S2 (cm s-1)

O1 (cm s-1)

K1 (cm s-1)

LMD Mixing 1.80 0.70 1.04 4.06 Brünt-Väisäla

Frequency Mixing 1.92 0.78 1.22 4.05

Mellor-Yamada 2.5 Level Closure

1.86 0.85 1.13 3.97

Pacanowski-Philander Mixing

1.94 0.64 1.37 4.33

GLS Mixing 1.79 0.76 1.20 4.11 LOAM Mixing 1.92 0.63 1.31 4.37

LMD without BKPP 1.86 0.78 1.21 3.92 Modified LMD 1.77 0.80 1.09 4.02

Red indicated absolute error values lower than those of the base case.

Page 17: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Comparisons to Observations (velocities)

Observations Model Results

32 25.75 N127 50.0 W

32 25.75 N127 50.0 W

32 26.56 N127 46.70 W

Major Axis (cm s -1 )

M2

LMD MY2.5 BVF PP

0 4 8

0

500

1000

1500

De

pth

(m

)

0 4 8 0 4 80 4 8 0 4 832 26.56 N127 46.70 W

0 4 8 12

0

200

400

600

De

pth

(m

)

0 4 8 120 4 8 12 0 4 8 12 0 4 8 12

K1

GLS

0 4 8 12

1500

1000

500

0

De

pth

(m

)

0 4 8 12 0 4 8 12 0 4 8 12 0 4 8 12

0 8 16

600

400

200

0

De

pth

(m

)

0 8 16 0 8 16 0 8 16 0 8 16

Flank (F3,F4,F5)

Center (P)

Flank (F3,F4,F5)

Center (P)

Page 18: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Vertical Diffusivity Observations

From Kunze et al. [1991]

Page 19: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Vertical Diffusivity (Temperature)

-4000

-2000

0

Dep

th (

m)

1E-006

1E-005

5E-005

1E-004

5E-004

1E-003

5E-003

Bottom

-4000

-2000

0

De

pth

(m

)

(m 2 s -1 )

-4000

-2000

0

Dep

th (

m)

-4000

-2000

0

Dep

th (

m)

32.0 32.2 32.4 32.6 32.8Latitude

-4000

-2000

0

Dep

th (

m)

127o 41.0' W

127o 41.0'W

127o 41.0' W

127o 41.0'W

127o 41.0'W

LMD

PP

BVF

MY2.5

GLS

Page 20: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Vertical Diffusivity (Temperature) (cont)

-4000

-2000

0

Dep

th (

m)

1E-006

1E-005

5E-005

1E-004

5E-004

1E-003

5E-003

Bottom

-4000

-2000

0

Dep

th (

m)

(m 2 s -1 )

-4000

-2000

0

Dep

th (

m)

-4000

-2000

0

Dep

th (

m)

32.0 32.2 32.4 32.6 32.8Latitude

-4000

-2000

0

Dep

th (

m)

127o 41.0' W

127o 41.0'W

127o 41.0' W

127o 41.0'W

127o 41.0'W

LOAM

PP

LMDno BKPP

LMDmodified

LMD

Page 21: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Vertical Diffusivity Observations

Page 22: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Vertical Diffuxivity (Temperature)

-1000

-500

0

Dep

th (

m)

1E-006

1E-005

5E-005

1E-004

5E-004

1E-003

5E-003

Bottom

-1000

-500

0

De

pth

(m

)

(m 2 s -1 )

-1000

-500

0

Dep

th (

m)

-1000

-500

0

Dep

th (

m)

32.40 32.42 32.44 32.46 32.48 32.50 32.52 32.54Latitude

-1000

-500

0

Dep

th (

m)

127o 41.0' W

127o 41.0'W

127o 41.0' W

127o 41.0'W

127o 41.0'W

LMD

PP

BVF

MY2.5

GLS

Page 23: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Vertical Diffusivity (Temperature)

-4000

-2000

0

Dep

th (

m)

1E-006

1E-005

5E-005

1E-004

5E-004

1E-003

5E-003

Bottom

-4000

-2000

0

De

pth

(m

)

(m 2 s -1 )

-4000

-2000

0

Dep

th (

m)

-4000

-2000

0

Dep

th (

m)

32.0 32.2 32.4 32.6 32.8Latitude

-4000

-2000

0

Dep

th (

m)

127o 41.0' W

127o 41.0'W

127o 41.0' W

127o 41.0'W

127o 41.0'W

LMD

PP

BVF

MY2.5

GLS

Page 24: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Summary

• Baroclinic tides were simulated using ROMS

• Semidiurnal tides were reproduced successfully

• Diurnal tides were not reproduced – Critical latitude effects– Mean currents insufficiently

simulated

• Generic Length Scale (GLS) produced the most realistic vertical diffusivities

• Acknowledgments – Data from Brink, Toole, Kunze, Noble, and Eriksen

Page 25: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Model Description Regional Ocean Modeling System (ROMS)  Primitive equation model; non-linear Split 2-D and 3-D modes  Boussinesq and hydrostatic approximations  Horizontal advection - 3rd order upstream

differencing [McWilliams and Shchepetkin]  Explicit vertical advection  Laplacian lateral diffusion along sigma

surfaces (1 m2 s-1)  LMD scheme for vertical mixing Exact baroclinic pressure gradient  Density based on bulk modulus  Tidal Forcing – M2, S2, O1, and K1

Elevations - set at boundaries  2-D velocities – radiation [Flather]  3-D velocities – flow relaxation scheme   tracers – flow relaxation scheme   Time Step - 4 s barotropic, 120 s baroclinc

mode   Simulation Duration: 30 days

Page 26: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Hydrography

32.0 32.2 32.4 32.6 32.8

Latitude

-4000.0

-3000.0

-2000.0

-1000.0

0.0

Dep

th (

m)

01234567891011121416

(o C)

from Levitus et al [1999]

Bottom

Vertical Cut at 127o 51.4' W

Page 27: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Evaluation of Operational Considerations and Parameterizations

Horizontal Resolution: Improving resolution improves agreement 1 km shows best agreement

Vertical Resolution: No. of Levels: Doubling the number of levels from 30 to 60 slightly

improved the agreement Increasing the number of levels to 90, showed no

improvement Spacing: Uneven spacing with more levels near the

surface and bottom improves agreement with observations

Best match - shallow mixed layer, S = 2, and B

= .5 Bathymetry:

Improvement with the finer scale Eriksen bathymetry Increased generation of internal tides on a small scale

Hydrography: Improvement with the finer scale Kunze hydrography

Baroclinic Pressure Gradient: Weighted Density Jacobian performed more poorly than

Spline Density Jacobian Vertical Mixing:

GLS showed the best agreement Horizontal Mixing: No appreciable effect

Page 28: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Sensitivity Study

• Bathymetry

• Hydrography

• Horizontal Resolution

• Vertical Resolution and Spacing

• Baroclinic Pressure Gradient Parameterization

• Vertical Mixing Parameterization

• Horizontal Mixing

Page 29: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Major Axis ErrorsParameter

Investigated

M2

(cm s-1) S2

(cm s-1) O1

(cm s-1) K1

(cm s-1)

Base Case

x, y =2 km; 60 levels;

unevenly spaced; Splines Density Jacobian BPG;

LMD Mixing

1.84

0.67

1.15

4.16

x, y =4 km (30 levels)

2.35 0.65 1.23 4.43 Horizontal Resolution x, y =1 km

(60 levels) 1.57 0.56 1.04 3.57

Bathymetry Smith & Sandwell

2.04 0.58 1.16 3.95

Hydrography Kunze 1.60 0.91 1.25 4.15 30 levels 1.89 0.76 1.39 4.15

90 levels 1.97 0.65 1.58 4.87 60 levels;

thermocline = 400m

S=1, B=1

1.91 0.66 1.36 4.23

60 levels; thermocline = 100m

S=1, B=1

1.85 0.76 1.28 4.07

60 levels; thermocline = 100m

S=2, B=1

1.88 0.67 1.35 4.17

Vertical Resolution and

Spacing

60 levels; thermocline = 100m

S=4, B=1

1.87 0.75 1.29 4.04

Baroclinic Pressure Gradient

Weighted Density Jacobian BPG

2.07 0.59 1.06 4.19

Brünt-Väisäla Frequency Mixing

1.98 0.76 1.32 4.14

Mellor-Yamada 2.5 Level Closure

1.92 0.83 1.23 4.07

Pacanowski-Philander Mixing

1.83 0.77 1.30 4.13

LOAM Mixing 1.92 0.74 1.39 4.23 LMD without BKPP 1.91 0.76 1.31 4.02

Modified LMD 1.81 0.78 1.20 4.12

Vertical Mixing

GLS Mixing 1.83 0.73 1.30 4.20

Red indicated absolute error values lower than those of the base case.

Page 30: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Bathymetry

-128.1 -127.9 -127.7 -127.5

Longitude

32.1

32.3

32.5

Lat

itu

de

1000

1500

2000

2500

3000

3500

4000

Smith and Sandwell fine scale from Eriksen

-128.1 -127.9 -127.7 -127.5

Longitude

32.1

32.3

32.5

32.7

Lat

itu

de

(m )

Page 31: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Bathymetry- M2

-4000

-2000

0

Dep

th (

m)

0.5

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

Bottom

-4000

-2000

0

Dep

th (

m)

(cm s -1 )

-4000

-2000

0

Dep

th (

m)

32.00 32.20 32.40 32.60 32.80

Latitude

-4000

-2000

0

Dep

th (

m)

127o 51.4' W

127o 51.4'W

127o 41.0' W

127o 41.0'W

S&S

Eriksen

S&S

Eriksen

Page 32: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Bathymetry- K1

-4000

-2000

0

Dep

th (

m)

0.5

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

Bottom

-4000

-2000

0

Dep

th (

m)

(cm s -1 )

-4000

-2000

0

Dep

th (

m)

32.00 32.20 32.40 32.60 32.80

Latitude

-4000

-2000

0

Dep

th (

m)

127o 51.4' W

127o 51.4'W

127o 41.0' W

127o 41.0'W

S&S

Eriksen

S&S

Eriksen

Page 33: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Horizontal Resolution – M2

-4000

-2000

0

Dep

th (

m)

0.5

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

Bottom

-4000

-2000

0

De

pth

(m

)

(cm s -1 )

-4000

-2000

0

De

pth

(m

)

-4000

-2000

0

Dep

th (

m)

32.0 32.2 32.4 32.6 32.8 33.0Latitude

-4000

-2000

0

De

pth

(m

)

127o 51.4' W

127o 51.4'W

127o 41.0' W

127o 41.0'W

127o 41.0'W

4 km

1km

4 km

2 km

1 km

Page 34: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Horizontal Resolution – K1

-4000

-2000

0

Dep

th (

m)

0.5

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

Bottom

-4000

-2000

0

Dep

th (

m)

(cm s -1 )

-4000

-2000

0

Dep

th (

m)

-4000

-2000

0

Dep

th (

m)

32.0 32.2 32.4 32.6 32.8 33.0Latitude

-4000

-2000

0

Dep

th (

m)

127o 51.4' W

127o 51.4'W

127o 41.0' W

127o 41.0'W

127o 41.0'W

4 km

1km

4 km

2 km

1 km

Page 35: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Comparison to Observations M2Observations 2 km

32 42.05 N128 2.70 W

32 28.64 N127 50.44 W

32 28.27 N127 48.57 W

32 26.56 N127 46.16 W

32 9.30 N128 0.49 W

32 25.75N127 50 W

32 24.61 N127 47.57 W

Major Axis (cm s -1 )

B2 F2 R2 C

B3 F3 R3

0 4 8

0

500

1000

1500

2000

2500

3000

3500

4000

4500

De

pth

(m

)

0 4 8 120 4 8 0 4 8 12

0 4 8

0

500

1000

1500

2000

2500

3000

3500

4000

4500

De

pth

(m

)

0 4 8 0 4 8 120 4 8 12

P 32 26.56 N127 46.70 W

1 km 4 km

Page 36: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Comparison to Observations K1Observations 2 km

32 42.05 N128 2.70 W

32 28.64 N127 50.44 W

32 28.27 N127 48.57 W

32 26.56 N127 46.16 W

32 9.30 N128 0.49 W

32 25.75N127 50 W

32 24.61 N127 47.57 W

Major Axis (cm s -1 )

B2 F2 R2 C

B3 F3 R3

0 4 8 12

0

500

1000

1500

2000

2500

3000

3500

4000

4500

De

pth

(m

)

0 4 8 12 160 4 0 4 8 12 16 20

0 4

0

500

1000

1500

2000

2500

3000

3500

4000

4500

De

pth

(m

)

0 4 8 12 0 4 8 12 160 4 8 12

P 32 26.56 N127 46.70 W

1 km 4 km

Page 37: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Comparison to Observations Mean Currents

Observations 2 km

32 42.05 N128 2.70 W

32 28.64 N127 50.44 W

32 28.27 N127 48.57 W

32 26.56 N127 46.16 W

32 9.30 N128 0.49 W

32 25.75N127 50 W

32 24.61 N127 47.57 W

Major Axis (cm s -1 )

B2 F2 R2 C

B3 F3 R3

0 10 20 30

0

500

1000

1500

2000

2500

3000

3500

4000

4500

De

pth

(m

)

0 10 200 10 0 10 20 30

0 10

0

500

1000

1500

2000

2500

3000

3500

4000

4500

De

pth

(m

)

0 4 8 12 0 10 200 10 20 30

P 32 26.56 N127 46.70 W

1 km 4 km

Page 38: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Baroclinic Pressure Gradient

Bottom

-4000

-2000

0

Dep

th (

m)

(cm s -1 )

-4000

-2000

0

Dep

th (

m)

-4000

-2000

0

Dep

th (

m)

32.0 32.2 32.4 32.6 32.8Latitude

-4000

-2000

0

De

pth

(m

)

127o 41.0'W

127o 41.0' W

127o 41.0'W

127o 41.0'W

0.5

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0M2

M2

K1

K1

SDJ

W DJ

SDJ

W DJ

Page 39: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Simulations 

Case Number

  

Purpose

 Horizontal Resolution

(x, y)

 Vertical

Resolution no. of levels)

Vertical Resolution:

Spacing(mixed layer,

S B)

 Baroclinic Pressure Gradient

 Vertical Mixing

 Horizont

al Mixing

 Other

1 Base Case 2 km 60 uneven(100,2,.5)

SDJ LMD 2nd Order

Laplacian

 

2 Horizontal Resolution

4 km 30 uneven(100,2,.5)

SDJ LMD 2nd Order

Laplacian

 

3 Horizontal Resolution

1 km 60 uneven(100,2,.5)

SDJ LMD 2nd Order

Laplacian

 

4 Bathymetry 2 km 60 uneven(100,2,.5)

SDJ LMD 2nd Order

Laplacian

Smith &

Sandwell5 Hydrography 2 km 60 uneven

(100,2,.5)SDJ LMD 2nd

Order Laplacia

n

Kunze

6 Vertical Resolution

2 km 30 uneven(100,2,.5)

SDJ LMD 2nd Order

Laplacian

 

7 Vertical Resolution

2 km 90 uneven(100,2,.5)

SDJ LMD 2nd Order

Laplacian

 

8 Vertical Resolution

2 km 60 even (400, 1, 1)

SDJ LMD 2nd Order

Laplacian

 

9 Vertical Resolution

2 km 60 even (100, 1, 1)

SDJ LMD 2nd Order

Laplacian

 

10 Vertical Resolution

2 km 60 uneven (100, 2, 1)

SDJ LMD 2nd Order

Laplacian

 

11 Vertical Resolution

2 km 60 uneven (100, 4, 1)

SDJ LMD 2nd Order

Laplacian

 

12 Baroclinic Pressure Gradient

2 km 60 uneven(100,2,.5)

Weighted Density

Jacobian

LMD 2nd Order

Laplacian

 

13 Vertical Mixing

2 km 60 uneven(100,2,.5)

SDJ Brünt-Väisäla Frequency

2nd Order

Laplacian

 

14 Vertical Mixing

2 km 60 uneven(100,2,.5)

SDJ Mellor-Yamada 2.5 Level Clos.

2nd Order

Laplacian

 

15 Vertical Mixing

2 km 60 uneven(100,2,.5)

SDJ Pacanowski-Philander

2nd Order

Laplacian

 

16 Vertical Mixing

2 km 60 uneven(100,2,.5)

SDJ LOAM 2nd Order

Laplacian

 

17 Vertical Mixing

2 km 60 uneven(100,2,.5)

SDJ LMD without BKPP

2nd Order

Laplacian

 

18 Vertical Mixing

2 km 60 uneven(100,2,.5)

SDJ LMD modified 2nd Order

Laplacian

 

19 Vertical Mixing

2 km 60 uneven(100,2,.5)

SDJ Generic Length Scale

2nd Order

Laplacian

 

20 Horizontal Mixing

2 km 60 uneven(100,2,.5)

SDJ LMD  1 m2 s-1

 

21 Horizontal Mixing

2 km 60 uneven(100,2,.5)

SDJ LMD 1x10-6

m2 s-1

 

22 Other 2 km 60 uneven(100,2,.5)

SDJ LMD 2nd Order

Laplacian

Latitude Shift

5oS

Page 40: Vertical Mixing Parameterizations and their effects on the skill of Baroclinic Tidal Modeling Robin Robertson Lamont-Doherty Earth Observatory of Columbia.

Inverse Richardson No.

-4000

-2000

0

Dep

th (

m)

0.01

0.10

1.00

4.00

Bottom

-4000

-2000

0

Dep

th (

m)

-4000

-2000

0

Dep

th (

m)

-4000

-2000

0

Dep

th (

m)

32.0 32.2 32.4 32.6 32.8Latitude

-4000

-2000

0

Dep

th (

m)

128o 1.7' W

127o 51.4'W

127o 41.0' W

127o 30.7'W

127o 20.4'W

Base Case (1)