Modeling Puget Sound Circulation

Mitsuhiro KawaseSchool of Oceanography

PRISM Retreat, 2002

National Ocean Partnership Program

A Partnership for Modeling the Marine Environment of Puget Sound, WashingtonONR Award N000140210503

Mitsuhiro Kawase, Allan Devol, Miles Logsdon and Mark Warner, School of Oceanography

William Winn, College of EducationUniversity of Washington, Seattle, WA

FY 02 Funding: $390,924

Objectives:

• Develop, maintain and operate a system of simulation models of Puget Sound’s circulation and ecosystem, a data management system for oceanographic data and model results, and an effective delivery interface for the model results and observational data for research, education and policy formulation.

• Develop fundamental understanding of the Sound’s working, and address questions raised by the regional community concerning management of the Sound and its resources.

Partners:

• Department of Natural Resources, King County, Washington (R. Shuman, B. Nairn)

• Department of Ecology, State of Washington (J. Newton)

• Puget Sound Naval Shipyard (S. Swanson, R. Johnston)

• Ocean Inquiry Project (F. Stahr, C. Sarason)

Puget Sound Circulation Model

• Support from National Oceanographic Partnership Program (NOPP), FY 2002 - 2008

• In collaboration with King County DNR• Based on Princeton Ocean Model (POM)

code• 360x540m resolution,14 vertical levels• Predicted variables: Velocity,

temperature, salinity, turbulent kinetic energy, turbulent master length

Model domain and bathymetry

Puget Sound Circulation Model (Cont’d)

• Hindcasting Year 2000 (with Bruce Nairn, KC-DNR):– Accurate time-average exchange circulation in the Main

Basin– Accurate time-average recirculation around Vashon Island

(northward current 30cm/s in Colvos Passage)– Excessive transport into the deep Whidbey Basin (~20%) -

dynamics of the Skagit Delta, Deception Pass transport?

Puget Sound Circulation ModelTasks FY 2002

• Complete coupling with the MM5 weather prediction model

• Routine hindcasting of Puget Sound circulation• Dynamics of Carr Inlet• Generate Lagrangian trajectories for study of

planktonic genetic diversity (diatoms, geoducks)

Variability at Seasonal/Interannual Time Scales

• Historical data analysis• Simple model of Puget Sound circulation for

quantitative sensitivity study

Schematic of exchange circulation in a fjord (cross-section)

Tidal Mixing

Entrance Sill

Main BasinMarine influence(Salty, Dense)

Sharp Pycnocline

River Input(Fresh, Light)

Outflow

Inflow/Reflux

Terrestrial Influence = River Runoff•Maximum in Winter/Spring

Marine Influence = Coastal Upwelling•Maximum in Spring/Summer

T/S Seasonal Cycle in Puget Sound Main Basin (1992)

T-S Variation 1992

6

7

8

9

10

11

12

13

14

29.4 29.6 29.8 30 30.2 30.4 30.6 30.8 31

Salinity (PSU)

Potential Temperature (degrees C) Februar

March

April

February 93

December

October/November

September

August

July

June 15

June 2

May

σ = 22.0 σ=22.5 σ=23.0

σ=23.5 σ=24.0

“Light Phase”

“Dense Phase”

A Box Model of Puget Sound Circulation

Amanda Babson, M.S. Thesis

• Twelve boxes to represent Puget Sound (six regions, upper and lower layer)

• Predicts salinity in each box, advective fluxes between boxes and mixing between upper and lower boxes

• Forced by river discharge and external salinity in deep Admiralty Inlet

• Conservation of mass and salt, simple parameterization of momentum and vorticity balance, and stratification-dependent vertical mixing

Salinity in a Box Model of Puget Sound Circulation (Babson, 2002)

Seasonal Transport in the Box Model (positive = out)

J F M A M J J A S O N D

-1.5

-1

-0.5

0

0.5

1

1.5

x 109

Volume Transport (m

3/day)

GhasGhadGchsGchdGmasGmadGnmsGnmdGwasGwadGpsGpdGd

Outflow at Surface

Inflow at Depth

Jan Apr Jul OctVol

um

e T

rans

port

(x1

09 cu

bic

met

ers

per

day)

0

1

-1

Potential Temperature 1999

June

December

Admiralty Inlet Sills

SJDF Dalco Passage

Main Basin

Black line: Last contiguous density surface across Admiralty Inlet

10

12

8

10

12

8

Salinity Anomaly, Puget Sound Main Basin at 100m

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

J-51

J-52

J-53

J-54

J-55

J-56

J-57

J-58

J-59

J-60

J-61

J-62

J-63

J-64

J-65

J-66

J-67

J-68

J-69

J-70

J-71

J-72

J-73

J-74

J-75

J-76

J-77

J-78

Date

Salinity Anomaly (permil)

Point No Point 100m Point Jefferson 100m Possession Point 100m

5000

10000

15000

20000

25000

-0.6 -0.4 -0.2 0 0.2 0.4 0.6

Salinity Anomaly (6 month averages)

Skagit River Discharge (6 month averages) R=0.6 (36% of variance)

Salinity and Potential Density in Central Puget Sound, 1990 - 1998(Blue: 100m Red: 200m)

28.5

29

29.5

30

30.5

31

Jan-89 Jan-90 Jan-91 Jan-92 Jan-93 Jan-94 Jan-95 Jan-96 Jan-97 Jan-98 Jan-99 Jan-00

Date

Salinity (PSU)

22

22.5

23

23.5

24

Jan-89 Jan-90 Jan-91 Jan-92 Jan-93 Jan-94 Jan-95 Jan-96 Jan-97 Jan-98 Jan-99 Jan-00

Date

Potential density (sigma theta)

1997: Year of no density intrusion

Salinity 1992-1999 in the Box Model

pre pre 92 93 94 95 96 97 98 99 post post24

26

28

30

32

Main Basin

Salinity (PSU)

surface datadeep data

model

pre pre 92 93 94 95 96 97 98 99 post post

20

25

30

Whidbey Basin

Salinity (PSU)

Note different scale

pre pre 92 93 94 95 96 97 98 99 post post24

26

28

30

32

N. Hood Canal

Salinity (PSU)

-1.5

-1

-0.5

0

0.5

1

1.5

J-51

J-52

J-53

J-54

J-55

J-56

J-57

J-58

J-59

J-60

J-61

J-62

J-63

J-64

J-65

J-66

J-67

J-68

J-69

J-70

J-71

J-72

J-73

J-74

J-75

J-76

J-77

J-78

Date

Temperature Anomaly (C)

Point No Point 100m Point Jefferson 100m Possession Sound 100m

Temperature Anomaly, Puget Sound Main Basin at 100m

-1.5

-1

-0.5

0

0.5

1

1.5

Jan-51 Jan-52 Jan-53 Jan-54 Jan-55 Jan-56 Jan-57 Jan-58 Jan-59 Jan-60 Jan-61 Jan-62

Date

Temperature Anomaly (C)

Point No Point 100m Point Jefferson 100m Possession Sound 100m

-3

-2.5

-2

-1.5

-1

-0.5

0

0.5

1

1.5

Jan-51

Jan-52

Jan-53

Jan-54

Jan-55

Jan-56

Jan-57

Jan-58

Jan-59

Jan-60

Jan-61

Jan-62

Date

Pacific Decadal Oscillation Index

R=0.57 (33% of variance)