Transcript Slide 1

Goal: Understand chemistry, biology and physics
of the Bay, at all points in the Bay, for all time
Goal 2: Understand coupled processes given any
combination of external forcing conditions
Physics:
Goal of Characterizing
Circulation,
Mixing,
Stratification
Flushing,
Transport, etc
Response
vs
Tides
Winds
Runoff
Density events
Etc.
Forcing
Methods are Observations & Modeling
Key physical processes
• Flushing dynamics
• Transport and mixing
• Deep water resupply
Goal: Understand chemistry, biology and physics
of the Bay, at all points in the Bay, for all time
RETENTION - MIXING/TRANSPORT - RESUPPLY
Use ADCP Data for Model Calibrations
•ADCP deployment in Providence River Narragansett Bay Comm.
x
Deployed July 7, 2005
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Use ADCP Data > RETENTION GYRE
•ADCP deployment in Providence River
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Deployed July 7, 2005
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Funding: NOAA, NBC
Flow in East Passage
Flow out West Passage
Flow in East Passage
Flow out West Passage
Good or Bad?
Good
How is deep return flow partitioned?
Flow in East Passage
Flow out West Passage
Good or Bad?
?
Good
Narragansett Bay
hydrodynamic modeling
Kincaid, Ullman, Bergondo,
Pfeiffer-Herbert, Balt, La Sota, Rogers
Funding: GSO-URI, Rhode Island Sea Grant, EPA-TMDL, Vetillson
Foundation, Narragansett Bay Commission, NOAA Hypoxia
Numerical Model
Initial Conditions
Forcing Conditions
Conservation
Equations
3D T, S, Velocity
ROMS Model
Regional Ocean
Modeling System
Output
ROMS history
1.Providence River
• Developed by D.
Bergondo
• N. La Sota’s thesis
2. NB-RIS
• J. Roger’s thesis
3. Narragansett Bay
• D. Ullman, C. Kincaid
& J. Rogers
Use Large Model to Drive Full Bay Model
Tides & Currents from
Newport ADCP & Tide
Data
Tides & Currents from
Roger’s Large Model
ADCIRC Forcing
Numerical Model: 1. CALIBRATION Effort
2. Process Studies
Initial Conditions
Forcing Conditions
Conservation
Equations
ROMS Model
Mixing coefficients
for salt, temp., momentum
Output
Model Calibration: J. Rogers URI, MS Thesis, 2008
Tidal Elevations Match Well
Instantaneous
Velocity
Fields
Match Well
Data=Red/Blue
Model=Pink/Cyan
Model Calibration (Temperature): J. Rogers URI, MS Thesis, 2008
Calibrated Model Applied to Bay Processes: Retention - Mixing/Transport - Resupply
J. Rogers URI, MS Thesis, 2008
How is deep return flow partitioned?
Flow in East Passage
Flow out West Passage
Good or Bad?
?
Good
Wind
Model Reveals
How Gyre Flux
Varies with
Wind & Runoff
QuickTime™ and a
decompressor
are needed to see this picture.
QuickTime™ and a
decompressor
are needed to see this picture.
How is deep return flow partitioned?
Flow in East Passage
Flow out West Passage
Good or Bad?
?
Good
Model Reveals
How Gyre Flux
Varies with
Wind & Runoff
Retention in Greenwich Bay
Are flushing rates a function of wind (speed & direction)?
Movie 1: NO WIND: Neutral density floats within GB
Movie 2: NNE - ward wind
Retention in GB (after 10 days)
No wind
NNE wind
QuickTime™ and a
decompressor
are needed to see this picture.
QuickTime™ and a
decompressor
are needed to see this picture.
Retention in GB (after 10 days)
No wind
NNE wind
12 Days
20 Days
Double gyre
retention pattern
GB
Normal flushing
pattern
WP
A)
B)
Wind (8 knots)
C)
Figure 1. Frames from a ROMS model run for summer stratification, intermediate tidal amplitude
and runoff and a prevailing (steady) 8 kt applied northeastward wind stress. Tracer floats are
used to track water parcels and provide an estimate of advective flushing time for the Greenwich
Bay (GB) system. A. Nearly initial tracer locations at day 180. B. After 12 days of simulation, only
a small fraction of tracers have left. Prevailing winds set up a double gyre system (shown
schematically with arrows) which limits exchange with the West Passage (WP). C. After 20 days
only 40% of tracers have flushed from GB, as opposed to ~90% flushing after ~3 days for cases
without this wind forcing (shown with arrows in A). The natural progression in the data-modeling
cycle is a time series deployment to test this model prediction of multi-gyre residual flow patterns
during specific wind conditions (locations shown in C).
Flushing of GB Strongly Dependent on Prevailing Winds
Wind Speed m/s (to northeast)
Rogers: Mid-Bay Exchange - Role of Wind Forcing
Goals
• Process-oriented:
– Simulate dynamics of flushing, mixing and
shelf-water intrusions
• Application-oriented:
– Provide exchange coefficients for ecological
box model
Providence River ROMS
Blackstone River
• High resolution
Woonasquatucket
• Fast computation River
Field’s Point
time
WWTF
• Boundary close to
Pawtuxet
River
area of interest
• Initial tests of
methodology
Moshassuck River
Ten Mile River
Bucklin Pt.
WWTF
East Providence
WWTF
Prov. River ROMS grid
Blackstone River
Moshassuck River
Ten Mile River
Woonasquatucket
River
Bucklin Pt.
WWTF
Field’s Point
WWTF
East Providence
WWTF
Pawtuxet
River
Conditions for Prov. River model runs
Average River flow (m3/s):
Blackstone - 22.1
Ten Mile - 3.1
Moshassuck - 1.1
Woonasquatucket - 2.1
Pawtuxet - 10
Average effluent flow (m3/s):
Field's Pt. - 2.17
Bucklin Pt. - 1.09 E.
Providence - 0.24
Average DYE concentration (mg/L):
Blackstone - 1.98
Ten Mile - 2.02
Moshassuck - 1.93
Woonasquatucket - 1.82
Pawtuxet - 2.63
Field's Point - 8
Bucklin Point - 8
E. Providence 8
Winds (mph):
Low NE - 0.5
Average NE - 8.4
High NE - 25.4
Low SW - 0.4
Average SW - 7.1
High SW - 18.5
Dye exchange coefficients
Dye exchange coefficients
Greenwich Bay, no wind
Greenwich Bay, NNE wind
Blackstone, Ten Mile,
Woonasquatucket, and
Moshassuck Rivers
Bucklin
WWTF
Field’s Point
WWTF
East Providence
WWTF
Pawtuxet
River
Open boundary
ROMS Projects:
Providence River Flushing: Nicole La Sota
-Dye boxes for CHRP modeling
-Nutrient releases from treatment facilities
NBC / Sea Grant:
Mid-Bay Physics: Justin Rogers
-Transport through mid-Bay
-Exchange with sub-regions
(Prov. River, Greenwich Bay, Mt. Hope Bay)
-Flushing of sub-regions vs. forcing trends
-Re-supply of deep water vs. forcing
Sea Grant / NOAA CHRP/ NBC
Bay-Rhode Island Sound Exchange: Anna Pfeiffer-Herbert
-Exchange vs. forcing
-Seasonal variations
-LARVAL dispersion
NOAA CHRP/ IGERT
Intermediate Scale Grid:
Goals:
1. Coverage from Seekonk
River to mouth of Narragansett
Bay
2. Fine resolution in key areas
of interest: Providence River, Mt. Hope
Bay, Ohio Ledge, Greenwich Bay
3. Total grid cells which still allow for
reasonable run times for model
simulations. (~10-30 days of simulation
per computer day).
ROMS history
1.Providence River
• Developed by D.
Bergondo
• N. La Sota’s thesis
2. NB-RIS
• J. Roger’s thesis
3. Narragansett Bay
• D. Ullman, C. Kincaid
Concluding Remarks
Goal: Understand Bay processes all positions & all time
Combination of good spatial/temporal data & modeling is a step in this direction
NBC Upper Bay Processes
Multiple projects:
System response
vs.
ExtentMt.of
Hopecounter
Bay circulation/exchange
/mixing study. ADCP, tide gauges
(Deleo, 2001)
Physical Forcing
NOAA: Mid-Bay Processes (-09)
Interdisciplinary Projects:
Coupling physics,
Chemistry, biology
Bay-RIS exchange study (98-02)
In 3D, moving boundary increase cells by factor ~200
or 100000 new cells!!!
SLOWS Calculation
Model Calibration (SALT): J. Rogers URI, MS Thesis, 2008
Retention Function of Winds
Wind Direction (towards)
NB-RIS ROMS
• Low resolution
• Slow computation
time
• Boundary far from
area of interest
Full Bay ROMS
• Moderate resolution
• Moderate
computation time
• Boundary
intermediate
distance from area
of interest
Applications for Management
Hydrodynamic/Transport Models of
Narragansett Bay & Rhode Island Sound
Deanna Bergondo
Chris Kincaid
Nicole La Sota
Anna Pfeiffer-Herbert
Justin Rogers
Dave Ullman
Funding: GSO-URI, Rhode Island Sea Grant, EPA-TMDL, Vetillson
Foundation, Narragansett Bay Commission, NOAA Hypoxia
Data-Model Spatial Flow Comparison: Fields Pt.
Summer, late ebb
outflow
inflow
outflow
inflow