Physical Science Team Meeting Minutes

November 2, 2000

NOAA/AOML/OCD

Participants (See Appendix B)

 

I.                    April Science Conference:

 

Peter Ortner opened the meeting with a discussion of the format of the April 26, 2001, Science Conference so that everyone clearly understood the central role to be played by the individual research teams.  This included synthesis presentation, delivery of a draft synthesis document to the PMC well prior to the Science Conference, poster presentation, and participation in a question and answer period with the Science Oversight Panel. 

 

A.                 Latest Developments

 

Tom Lee began a roundtable discussion of new results and future research plans.  Together, RSMAS and AOML have completed three years of moored observations on the southwest shelf and Keys coastal zone with excellent data recovery, including such events as tidal, wind forcing, transient storms and interannual variations caused by El Nino. Analysis is underway to present results of the 3-year current/T/C/P measurements at the April Science Conference. Future plans involve real-time monitoring on the southwest shelf and Keys and seasonal process studies of exchange processes in the inner basins of Florida Bay to directly address the concerns expressed by the Florida Bay Science Oversight Panel.

 

Bill Nuttle presented reprints of a recent paper on salinity variability in Florida Bay using the Fathom box model. He is also briefly described a new project to estimate evaporation rates and radiation budgets in Florida Bay using an isotopic approach and two met towers to evaluate spatial variability.

 

Libby Johns discussed ongoing analysis of salinity variability observed in the regional ship surveys and the inner basin Florida Bay surveys with regard to large changes observed from recent hurricane influences.

 

Doug Wilson described ongoing analysis of moored conductivity measurements in the Shark River plume and planned drifter studies for the seasonal inner basin studies.

 

Sandy Vargo reviewed the status of eight real-time C-MAN monitoring stations located along the Keys and in western Florida Bay.  Four of these stations are now equipped with water level recorders and transmissometers i.e., Long Key, Sombrero, Northwest Florida Bay, and Sands Key. All stations have in water T and C measurements.

 

DeWitt Smith reported that he and Mike Robblee are compiling all the available salinity data that will, in turn, be incorporated into the Florida Bay Standard Data Set. DeWitt is also working on the influences of Hurricanes Irene and Harvey and a tidal analysis of sea level along the western coast of the Ten Thousand Islands.

 

Frank Marshall mentioned that he is working on transfer functions using multiple regression that can be used for salinity performance measures. He uses water levels from flow control structures and regresses with salinity observed in the bays along the northern boundary of Florida Bay. He is able to reproduce historical results but when longer time periods are used the regression coefficients decrease.

 

John Wang reported that he has completed two modeling scenarios for South Biscayne Bay circulation and salinity distribution using different fresh water discharges. He has also quantified the exchange between offshore currents and the shelf region off Biscayne Bay using OSCR data.

 

Zafer Top gave a presentation on recent work using helium and tritium analysis of water samples from an array of stations in Florida Bay to estimate ground water input to Florida Bay.  He found significant excesses of He in stations along the northern boundary and interprets this as due to groundwater input at a rate of 2 to 4 and up to 16 cm/day. Members of the PST pointed out that this did not match either estimates of residence times or observed seasonal salinity patterns. A groundwater input of 1 cm/day would require a volume flow of 230 m³/sec, which was not felt to be physically reasonable. The cause of the discrepancy between these groundwater flow estimates and salinity observations was not clear. PST members agreed to investigate the implications to model dynamics and calculated residence times, salinities and transports of groundwater inputs of this scale.  If Zafer supplied the salinity of the groundwater, the mass-balance FATHOM modelers agreed to determine the degree to which that amount of input could be accommodated without disrupting the observed salinity distribution which was reasonably well reproduced by FATHOM without any groundwater input.  

 

Zaki Moustafa reported on the progress of his pilot project applying a hydrodynamic model to Florida Bay that was originally developed at Virginia Institute of Marine Science and is in the public domain. The western boundary is at 81⁰ 05¢ and uses the USACE’s ADCP data as a boundary condition. The model is “3D”, has 4330 cells, and is spatially coarse compared to the RMA-10.  So far, he has primarily been occupied by data gathering, but the model is up and running. The model provides currents and salinity distributions and could be used to evaluate different freshwater discharge scenarios with short run times, i.e. rapid turnaround. The model is expected to be ready in early 2001.  A full report with documentation will be provided the entire PST two weeks prior to a meeting devoted to a substantive review.  The SFWMD has made no commitment to subsequent development of this model pending the PST review. 

 

B.         Develop Outline for Question 1 Synthesis (Draft Synthesis due February 15, 2001)

 

Question 1: How, and at what rates, do storms, changing freshwater flows, sea level rise, and local evaporation/precipitation patterns influence circulation and salinity patterns within Florida Bay and outflows from the Bay to adjacent waters?

 

1)      List of Research Themes related to Question 1

2)      Map of Measurement Locations

3)      Event Time Line (showing when measurements are made)

4)      Discussion of Research Themes

What has been learned

Importance to Question 1

Unanswered questions

5)      Ongoing Research

Map showing future measurement strategies

Relation to Question 1

6)      Future Needs

 

C.           Assignment of Responsibilities for Synthesis Report and Presentation

 

Research Themes

 

1)      Fresh Water Inflows (surface and groundwater flows into Florida Bay)

 

Responsibility of Frank Marshall and Eric Swain(?)

 

8 Abstracts:            Cable et al.

                                                Hittle

                                                Marshall

                                                Schaffranek et al.

                                                Swain and Langevin

                                                Swart and Price

                                                Vosburg et al.

                                                Wolfert et al.

                                                Top et al.

                                                Additional abstract solicited from Patino

 

2)      Salinity Variability (spatial and temporal variability within Florida Bay and connecting

Regions)

 

Responsibility of Elizabeth Johns and DeWitt Smith

 

6 Abstracts:            Cronin et al.

                                                Johns et al.

                                                Smith et al.

                                                Johns et al.

                                                Robblee et al.

                                                Wardlaw

 

3)      Circulation and Exchange (spatial and temporal circulation patterns, transports,

exchanges between the Gulf, Florida Bay and the Atlantic)

 

Responsibility of Tom Lee and Ned Smith

 

3 Abstracts:            Lee et al.

                                                Pitts

                                                Smith

 

4)      Atmospheric Forcing (winds, evaporation, and precipitation)

 

Responsibility of Rene Price and Bill Nuttle

 

1 Abstract: Price et al  (evaporation)

                              Additional abstracts solicited from Mattocks, Trimble, and Willis

 

5)      Modeling (Florida Bay circulation and salinity, atmospheric forcing, boundary conditions from large-scale shelf model, hydrologic inflow models, and Standard Data Set)

 

Responsibility of Peter Ortner and Tom Lee with advice from Frank Aikman

 

3 Abstracts:            Schaffranek et al. (freshwater inflows)

                                                Swain and Langevin (freshwater inflows)

                                                Wolfert et al. (freshwater inflows)

                                                Abstract to be submitted by Moustafa

 

6)      General Use Maps and Time Lines

 

Responsibility of Joe Pica

 

            Responsibilities of Synthesis Organizers

 

·        Review abstracts related to theme

·        Contact abstract authors for additional information

·        List and summarize abstracts as related to theme

·        Synthesize the following for each theme:

a)      What has been learned?

b)      Importance to Question 1

c)      Unanswered questions

d)      Ongoing Work

e)      Future needs

 

Synthesis Presentation

 

Responsibility:  Tom Lee

 

II.                 Modeling Needs with Regard to Question 1

 

A.                 Review of Status/”Feasibility Study” Time Clock

 

Peter Ortner led a discussion of the Florida Bay and Florida Keys Feasibility Study. There is an urgent need to investigate the influence of proposed water delivery scenarios to the Everglades on salinity variability in Florida Bay South Florida coastal systems. The USACE is no longer involved in the effort with their RMA10 hydrodynamic model. Funding for the Feasibility Study is available at about $1M/yr for 4 years. The time clock for needed input is two years from October 2000. The Feasibility Study outcome will determine what, if any, additional restoration actions (as yet uncontemplated in CERP) must be taken in regard to Florida Bay and the Florida Keys. Additional funding may be available from the DOI’s Critical Ecosystems Studies Initiative (CESI) for modeling studies that can yield improved predictions of salinity changes under different water delivery scenarios. This objective implies more than just modeling salinity variation within Florida Bay but also requires much improved assessment of the distribution and quantity of freshwater inflows under the different scenarios.

 

B.                 Discussion of Terms of Reference

 

Peter Ortner presented a draft of Circulation Modeling Terms of Reference for discussion. Comments from the PST were:

 

1)       Terms of reference provide too much leeway, most models could claim to satisfy these

        seven items.

2)       Need to be more specific about physical processes to model, methods to be used and

        standards to use to validate the results.

3)       Modelers should work closely with the team of investigators that are actively engaged

 in physical process studies within Florida Bay.

 

Members of the PST (T.Lee, B.Nuttle, J.Wang, Z. Moustafa, and F.Aikman[?]) agreed to help improve the Terms of Reference (new version attached as Appendix C). Not all their input has, as yet, been received and incorporated.

 

III.               Standard Data Set for Florida Bay

 

Bill Nuttle reviewed the results from the Standard Data Set Workshop Report which was provided to participants prior to the PST meeting.

 

A.                 Workshop Summary

 

The Standard Data Set covers the six-year period from October 1994 to October 2000. This time period was chosen due to the large concentration of measurements. The Standard Data Set is made up of three broad types of data: 1) salinity, 2) estimates of freshwater fluxes, and 3) oceanographic and climate data. The data set will be 1) used to validate models, 2) as a common point of reference for studies of wet and dry seasons, and 3) to characterize links between Everglades hydraulics and salinity variability in Florida Bay.

 

B.         Project status

 

Joe Pica will continue to request data from investigators. Some data sets are still being processed by the source agency.   Flat files will be made available on a web page.  Station metadata will be entered into an Geographical Information System that is set up for queries.  

 

1)      Oceanographic (tides, currents, CTD profiles, T/S continuous surveys)

2)      Climate (rainfall, air temperature, dew point [humidity], wind speed and direction, solar

radiation, pan evaporation)

3)      Water Quality (salinity, water temperature)

 

B.                 Completion Strategy

 

Joe will continue to request data from investigators. Some data sets still being processed.  Initially, flat files will be provided.  Eventually, however, data will be entered into an Oracle database that is set up for queries.  

 

IV.              Salinity Performance Measures for Florida Bay

 

Bill Nuttle presented results from a July 13, 2000, meeting on salinity performance measures.

 

A.        Present Measures

 

The current performance measure consists of a linear regression based on water levels at P33 and salinity in northern coastal bays of Florida Bay.  This regression has been used by water management since Tabb (1967) first found a regression coefficient of about -0.8 using a relatively short data record. Recent studies by Frank Marshall have been able to recreate the Tabb relationship but, using longer data records, found much reduced regression coefficients. The P33 regression does not appear to be reliable due to influences from water management that can cause large error bars.  Discussion related to the fact that the high correlation with the well was likely to be caused by covariance with precipitation. 

 

C.                 Future Plans

 

Studies are underway to use more robust techniques to relate Everglades hydrology and water management to total flow into Florida Bay which is, in turn, required to predict salinity variability in Florida Bay.  Discussion focused upon explicit representation of fresh water runoff including consideration of the Buttonwood Embankment using more appropriate rainfall measurements (Royal Palm rather than Flamingo in some cases) and more complex statistical methods incorporating high frequency daily flow data rather than long-term averages.  There was also discussion of a more general long-term strategy.  It was generally agreed that inflow improvement and local salinity variability e.g., Joe Bay or Little Madeira, might best be addressed by a rigorous statistical approach. However, predicting salinity variability over the entire Bay (not to mention understanding advective pathways) will require a relatively sophisticated hydrodynamic model.  Moreover, development and verification of the hydrodynamic model will require timely completion of the Standard Data Set project. The consensus was that all three activities (improved statistical predictors, hydrodynamic modeling, and the Florida Bay Standard Data Set) will have to be simultaneously pursued to meet the timelines and requirements of CERP and the Feasibility Study.  Funding should be made available to do this from one or a combination of the Feasibility Study partners, available DOI/CESI funds or other PMC agency sources.