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Circulation in Narragansett Bay: Water flow & mixing Transport of chemical-biological material Exchange between

Circulation in Narragansett Bay: Water flow & mixing Transport of chemical-biological material Exchange between sub-regions of Bay. Motivation: Episodic hypoxia in NB & Developing management tools for the Bay ecosystem. CHRP Coupled Ecological Modeling (GEMBox - ROMS Model).

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Circulation in Narragansett Bay: Water flow & mixing Transport of chemical-biological material Exchange between

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  1. Circulation in Narragansett Bay: Water flow & mixing Transport of chemical-biological material Exchange between sub-regions of Bay

  2. Motivation: Episodic hypoxia in NB & Developing management tools for the Bay ecosystem CHRP Coupled Ecological Modeling (GEMBox - ROMS Model) Fundamental Column: Detailed understanding of physical processes Biological processes Chemical Processes National Capitol Columns at the United States National Arboretum in Washington, D.C.

  3. Role of physical processes in the health of the Bay • Physical Drivers: • Tides • Winds • River discharge • Density differences http://www.geo.brown.edu/georesearch/insomniacs

  4. Role of physical processes in the health of the Bay • Physical Drivers: • Tides • Winds • River discharge • Density differences • Out with the bad http://www.geo.brown.edu/georesearch/insomniacs

  5. Role of physical processes in the health of the Bay • Physical Drivers: • Tides • Winds • River discharge • Density differences • Out with the bad • In with the good http://www.geo.brown.edu/georesearch/insomniacs

  6. Circulation in Narragansett Bay: 3 Basic MethodsHydrographic data (currents, density) Numerical Modeling (ROMS : ( Regional Ocean Modeling System) Physical - Laboratory Modeling

  7. Physics: Observations Acoustic Doppler Current Profilers Bottom mounted Ship mounted / underway Data coverage: Excellent temporal Poor Spatial Data coverage: Good spatial Poor Temporal

  8. Tilt Current Meters : (tilt proportional to water velocity) Water flow Buoyant cylinder Flexible membrane Mooring weight

  9. Numerical Model Shallow Water Equations Momentum balance x & y directions: u + vu – fv = f + Fu + Du t x v + vv + fu = f + Fv + Dv ty Potential temperature and salinity : T+ vT = FT + DT t S + vS = FS + DS t The equation of state: r= r (T, S, P) Vertical momentum: f = - r g z ro Continuity equation: u+v+w = 0 x y z Initial Conditions Forcing Conditions ROMS Model Regional Ocean Modeling System Output

  10. Fluid Dynamics Laboratory Models (a.k.a analog models) Save the Bay Hurricane Barrier Fall, 2008 at GFD Lab, Australian National University: . Developed flume tank to represent the upper Providence River Lab models provide excellent check against numerical models Edgewood Shoal Shipping Channel Shipping Channel Save the Bay Edgewood Shoal Port Edgewood

  11. Circulation in Narragansett Bay: 3 Basic MethodsLots of great students!! Bridget Sullivan (1st developed SCRUM, then ROMS) William Deleo (data at Bay Mouth, detailed study of Mt. Hope Bay) Kurt Rosenberger (data at Bay Mouth and in Rhode Island Sound) Deanna Bergondo (develop ROMS model/data for Providence River, initial CHRP proposal) Justin Rogers (ROMS, Mid-Bay Data ) Nicole LaSota (ROMS Prov. River dye dispersion study) Anna Pfeiffer-Herbert (Detailed data RIS, mouth, Greenwich Bay, Bay-Shelf Exchange) Christelle Balt (Greenwich Bay & Prov. River Data, ROMS flushing exeriments, Mixing schemes)

  12. Circulation in Narragansett Bay: 3 Basic MethodsLots of great studentsHeaps of excellent support Bridget Sullivan (1st developed SCRUM, then ROMS) William Deleo (data at Bay Mouth, detailed study of Mt. Hope Bay) Kurt Rosenberger (data at Bay Mouth and in Rhode Island Sound) Deanna Bergondo (develop ROMS model/data for Providence River, initial CHRP proposal) Justin Rogers (ROMS, Mid-Bay Data ) Nicole LaSota (ROMS Prov. River dye dispersion study) Anna Pfeiffer-Herbert (Detailed data RIS, mouth, Greenwich Bay, Bay-Shelf Exchange) Christelle Balt (Greenwich Bay & Prov. River Data, ROMS flushing exeriments, Mixing schemes)

  13. Quick summary: PR RI Sea Grant GB MHB NB Bridget Sullivan (1st developed SCRUM, then ROMS) William Deleo (data at Bay Mouth, detailed study of Mt. Hope Bay) Kurt Rosenberger (data at Bay Mouth and in Rhode Island Sound) Deanna Bergondo (develop ROMS model/data for Providence River, initial CHRP proposal) Justin Rogers (ROMS, Mid-Bay Data ) Nicole LaSota (ROMS Prov. River dye dispersion study) Anna Pfeiffer-Herbert (Detailed data RIS, mouth, Greenwich Bay, Bay-Shelf Exchange) Christelle Balt (Greenwich Bay & Prov. River Data, ROMS flushing exeriments, Mixing schemes) 1999-2001 RIS

  14. Narragansett Bay Commission 2001-2005 PR GB MHB NB Bridget Sullivan (1st developed SCRUM, then ROMS) William Deleo (data at Bay Mouth, detailed study of Mt. Hope Bay) Kurt Rosenberger (data at Bay Mouth and in Rhode Island Sound) Deanna Bergondo (develop ROMS model/data for Providence River, initial CHRP proposal) Justin Rogers (ROMS, Mid-Bay Data ) Nicole LaSota (ROMS Prov. River dye dispersion study) Anna Pfeiffer-Herbert (Detailed data RIS, mouth, Greenwich Bay, Bay-Shelf Exchange) Christelle Balt (Greenwich Bay & Prov. River Data, ROMS flushing exeriments, Mixing schemes) 99-01 RIS

  15. Narragansett Bay Commission & CHRP award, 2006 2005 PR GB 2006 MHB NB Bridget Sullivan (1st developed SCRUM, then ROMS) William Deleo (data at Bay Mouth, detailed study of Mt. Hope Bay) Kurt Rosenberger (data at Bay Mouth and in Rhode Island Sound) Deanna Bergondo (develop ROMS model/data for Providence River, initial CHRP proposal) Justin Rogers (ROMS, Mid-Bay Data ) Nicole LaSota (ROMS Prov. River dye dispersion study) Anna Pfeiffer-Herbert (Detailed data RIS, mouth, Greenwich Bay, Bay-Shelf Exchange) Christelle Balt (Greenwich Bay & Prov. River Data, ROMS flushing exeriments, Mixing schemes) 99-01 RIS

  16. Narragansett Bay Commission RI Sea Grant & CHRP award, 2007 2005 PR GB 2006 MHB NB 2007 Bridget Sullivan (1st developed SCRUM, then ROMS) William Deleo (data at Bay Mouth, detailed study of Mt. Hope Bay) Kurt Rosenberger (data at Bay Mouth and in Rhode Island Sound) Deanna Bergondo (develop ROMS model/data for Providence River, initial CHRP proposal) Justin Rogers (ROMS, Mid-Bay Data ) Nicole LaSota (ROMS Prov. River dye dispersion study) Anna Pfeiffer-Herbert (Detailed data RIS, mouth, Greenwich Bay, Bay-Shelf Exchange) Christelle Balt (Greenwich Bay & Prov. River Data, ROMS flushing exeriments, Mixing schemes) 99-01 RIS

  17. RI Sea Grant & CHRP award, 2008 2005 PR GB 2006 MHB NB 2007 Bridget Sullivan (1st developed SCRUM, then ROMS) William Deleo (data at Bay Mouth, detailed study of Mt. Hope Bay) Kurt Rosenberger (data at Bay Mouth and in Rhode Island Sound) Deanna Bergondo (develop ROMS model/data for Providence River, initial CHRP proposal) Justin Rogers (ROMS, Mid-Bay Data ) Nicole LaSota (ROMS Prov. River dye dispersion study) Anna Pfeiffer-Herbert (Detailed data RIS, mouth, Greenwich Bay, Bay-Shelf Exchange) Christelle Balt (Greenwich Bay & Prov. River Data, ROMS flushing exeriments, Mixing schemes) 99-01 RIS 2008

  18. RI Sea Grant & CHRP award, 2009 Most ambitious physical sampling survey ever….. Focus on key CHRP Dye Boxes 2005 PR GB 2006 2009 MHB NB 2007 Bridget Sullivan (1st developed SCRUM, then ROMS) William Deleo (data at Bay Mouth, detailed study of Mt. Hope Bay) Kurt Rosenberger (data at Bay Mouth and in Rhode Island Sound) Deanna Bergondo (develop ROMS model/data for Providence River, initial CHRP proposal) Justin Rogers (ROMS, Mid-Bay Data ) Nicole LaSota (ROMS Prov. River dye dispersion study) Anna Pfeiffer-Herbert (Detailed data RIS, mouth, Greenwich Bay, Bay-Shelf Exchange) Christelle Balt (Greenwich Bay & Prov. River Data, ROMS flushing exeriments, Mixing schemes) 99-01 RIS 2008

  19. Data tell a physical story…….. Providence River Model Full Bay Model Domain RIS-NB Model Domain(Rogers, 2008)

  20. Data Example Circulation and Transport in Upper Narragansett BayJustin RogersMS Thesis,08

  21. West Passage (Tidal flows) North - IN Surf. Fast in, Faster out Bot. East Passage Channel (Tidal flows) North - IN Slow in, Slowerout Decimal Day in 2006 (summer)

  22. Examples what these data look like: Data tell a physical story……..over lots of different scales (different forcing) Providence River Model Full Bay Model Domain RIS-NB Model Domain(Rogers, 2008)

  23. Residual (de-tided) Flow West Passage On-average…southward Surface Bottom

  24. Residual (de-tided) Flow West Passage On-average…southward Surface Bottom East Passage Channel On-average…northward

  25. Physical Story of the Bay, by Residual Q. Data Water enters eastern EP Dominant re-supply up EP Outflow through WP* ------------------------------------------------- Enhance: Eastward winds Southward winds Northward, then Southward winds Stall/reverse: Northwestward winds stall / reverse ?

  26. We have a very good idea about deep intrusions where they come from, what drives them, and their thermal advection Steady Re-supply up East Passage Enhanced by: Eastward winds Southward winds Northward, then Southward winds Deep EP Bottom Temperature @ ADCP ?

  27. Data tell a physical story…. Data always limited in space and/or time….. Models extend us towards full physical story of the Bay, all places, for all time Providence River Model Full Bay Model Domain RIS-NB Model Domain(Rogers, 2008)

  28. Data tell a physical story…. Data always limited in space and/or time….. Models extend us towards a full physical story of the Bay, all places, for all time ------------------------------------------------------------------------------------------------------ Models….do we trust them? do the data and model wiggles match? Providence River Model Full Bay Model Domain RIS-NB Model Domain(Rogers, 2008)

  29. ROMS Modeling for Narragansett Bay is built on years of GSO student efforts Bergondo: Providence River model Rogers: Bay - Rhode Island Sound Model Rogers, Ullman, Balt: Full Narragansett Bay Model Providence River Model Full Bay Model Domain RIS-NB Model Domain(Rogers, 2008)

  30. ROMS Modeling for Narragansett Bay is built on years of GSO student efforts Bergondo: Providence River model Rogers: Bay - Rhode Island Sound Model Rogers, Ullman, Balt: Full Narragansett Bay Model Providence River Model 2006 wind, runoff, air conditions Tides, mouth forced by large model 15 terrain-following vertical coordinates <50 meter horizontal grids Full Bay Model Domain RIS-NB Model Domain(Rogers, 2008)

  31. Models match instantaneous (tidal) flows/heights very well Skill = .97 Data ( R) vs Model (B) Tidal response Skill = .98 Water Level Skill = .98 Decimal Day, 2006

  32. Validation using fixed- point data 2006 From C. Balt,09

  33. Actual forcing data ROMS Model ROMS Assessment : Quantitative comparisons with fixed station data Time series model output at buoy locations + Time series buoy data Statistical metrics: Skill = 0 poor Skill = 1 perfect Tide heights: Skill >0.95 // Velocity fields: Skill 0.8 - 0.9 // T,S: Skill 0.75-0.98

  34. Data tell a physical story…. Data always limited in space and/or time….. Models extend us towards a full physical story of the Bay, all places, for all time ------------------------------------------------------------------------------------------------------ Models….do we trust them? do the data and model wiggles match? does the model predict the gross character shown in data? Providence River Model Full Bay Model Domain

  35. Modeled upper bay transport: Vertically integrated along N. Prudence Line --- Zero wind Summer 2006 forcing, except winds

  36. Modeled upper bay transport: Vertically integrated along N. Prudence Line --- Zero wind --- Northward wind GYRE STALLS

  37. Modeled upper bay transport: Vertically integrated along N. Prudence Line IN OUT --- Zero wind --- Northward wind GYRE STALLS --- Southwestward wind GYRE ENHANCED Patterns match 06-09 ADCP data

  38. Data tell a physical story…. Data always limited in space and/or time….. Models extend us towards a full physical story of the Bay, all places, for all time ------------------------------------------------------------------------------------------------------ Models….do we trust them? do the data and model wiggles match? does the model predict the gross character shown in data? Quasi-trusted models….how can we use them? Providence River Model Full Bay Model Domain RIS-NB Model Domain(Rogers, 2008)

  39. Key Management Issue: The role of flushing dynamics as the root of chronic water quality problems? Out with the Bad http://www.geo.brown.edu/georesearch/insomniacs

  40. Flushing Time using Fraction of Water Method (assume complete mixing) Simple estimates: ~4 days Simple estimates: ~10 days

  41. Flushing processes may be more complex……. Greenwich Bay: Rogers thesis models using ROMS show longer times Future: Test model predictions with dense current meter network Providence River: NBC data & Fluid Dynamics Lab Models suggest longer times Future: Test predictions using dense current meter network

  42. Flushing processes may be more complex……. Greenwich Bay: Rogers thesis models using ROMS show longer times Future: Test model predictions with dense current meter network Providence River: NBC data & Fluid Dynamics Lab Models suggest longer times Future: Test predictions using dense current meter network CHRP models must represent flushing accurately

  43. Providence River flushing may not follow simple estimates Models & Data Suggest a Bimodel Residence Time channel NBC Save the Bay Edgewood shoals EYC

  44. Fluid Dynamics Laboratory Models (a.k.a analog models) Save the Bay Hurricane Barrier Fall, 2008 at GFD Lab, Australian National University: . Developed flume tank to represent the Providence River Model includes shipping channel & the Edgewood Shoals Parameters: river flow , NBC discharge, tides : (no winds) Edgewood Shoal Shipping Channel Shipping Channel Save the Bay Edgewood Shoal Port Edgewood

  45. We have modified a 3 meter long flume tank at the Fluid Dynamics Lab of the Australian National University to represent the Providence River-Fields Point- Edgewood region of the estuary. NBC NBC Port Edgewood Port Edgewood Broad Shoal Channel Broad Shoal Channel 66 cm (1000m) Z= 2cm 33 cm (400 m)

  46. Scaling: Re#= 105 Scale on runoff prism and tidal prism : 30 CMS = 7 liters/min 1 tide cycle = 20 seconds Channel NBC Broad Shoal

  47. Relevance to Water Quality Models Lab Models: small physics that numerical models can’t represent Do small scale processes influence exchange & mixing between shoal and channel & overall water quality? Channel NBC Broad Shoal

  48. Movies: no wind/density forcing 30 CMS (7liters/min), no tide (2 CMS NBC Fields Pt). 2 CMS runoff, 1.5 meter tide 30 CMS & 1 meter tide (late addition of 2 CMS NBC outfall) Channel NBC Broad Shoal

  49. Do small scale processes influence exchange & mixing? YES Lab Models: Discharge, no tide Eddies 10-50 meters Small scale eddies: tilted/sheared Vertical & horizontal structure to shoal-channel exchange: >15 days: shoal bottom water retention Surface floaters rapid exchange, but recycle

  50. Do small scale processes influence exchange & mixing? YES Spring tide only, no runoff: Mid-shoal surface off in 4 cycles (2 days) Mid-shoal deep >> 10 cycles (5 days) Inside shoal >> 10 cycles (5 days)

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