September 4 - 5, 1997

Miami, Florida

The first workshop of the Florida Bay Physical Science Team was held in Miami on September 4^th and 5^th. The purpose of the meeting was to facilitate communication and integration between physical scientists (including modelers) conducting research in Florida Bay. The workshop focused on an update of current projects and a discussion of critical gaps in data collection and information needs. Participants also discussed data exchange and assimilation as well as integration with modeling needs and compatibility between projects. By all accounts the meeting was a success and generated the recommendations below for consideration by the PMC and its appropriate agency representatives.

RECOMMENDATIONS

During the presentations it was clear that measurements and a modeled field of evaporation within Florida Bay were absent. Because one of the main research efforts within the Bay is modeling salinity response to changes in freshwater input, an accurate assessment of evaporation (E) is essential. While some progress has been made at estimating rainfall (P), the critical parameter is really P-E. Evaporation is currently being investigated in regions upstream of Florida Bay; however, only very coarse estimates have been derived for the Bay itself. The consensus of the group was that while these estimates may be a reasonable first approximation for evaporation over the entire Bay, a more detailed assessment of evaporation both in space and time is required for the purpose of modeling salinity changes. As such, several approaches to obtaining an estimate of evaporation were discussed which include the following:

• Measurements of sea surface temperature, air temperature, atmospheric pressure (could be estimated), relative humidity, and wind speed could be obtained throughout the Bay over extended time periods.
• These measurements could be partially accomplished by sensor additions to the current network of National Park Service (NPS) stations in the Bay.
• Station data should be supplemented with measurements from banktop regions. We were in general agreement that evaporation occurs unevenly throughout the Bay and is probably highest on restricted banktop sites.
• Establish one banktop monitoring site and supplement it with a more detailed process-oriented study covering a specific bank and basin area over a relatively short period of time (at least 24 hours).

Other suggestions regarding possible techniques to measure evaporation included the use of satellite imagery (pixel size may make this approach of limited use) and the isotope geochemistry of surface waters.

A theme echoed in subsequent discussions was that physical measurements within the Bay are now focused on time-series types of data representative of broad-scale processes. Participants suggested that given the degree of heterogeneity within the Bay, these data must be supplemented by more small-scale, shorter time period, process-oriented studies (not only evaporation, but salinity, temperature and current flow).

All participants agreed that the current effort to establish a SEAKEYS station in northwest Florida Bay will be extremely helpful and provide important data. The possibility of establishing another SEAKEYS station further to the north off Cape Romano was also discussed. Unfortunately, it appears that the Coast Guard has been having difficulty keeping platforms in place due to the shifting sands in this region. Further information regarding the bottom is necessary before pursuing the installation of a new station off Cape Romano. If the bottom is not suitable, perhaps, it may be possible to locate a station nearby.

Participants also discussed the need for additional time-series data. While this data may not be directly pertinent to the Florida Bay program, they could be very important for the overall South Florida Restoration program. For example, to better assess the impact of Florida Bay waters upon the Florida Keys National Marine Sanctuary (FKNMS) reef tract, NOAA has funded Florida Institute of Oceanography (FIO) to add additional sensors (transmissometers and fluorometers) to stations already in place that monitor temperature, salinity, and meteorological variables. This SEAKEYS data is processed and distributed in near real-time via a NOAA/AOML's web site. For minimal additional funding, real-time current profiles (ADCP) from adjacent bottom sites could be telemetered ashore along with SEAKEYS platform data at Sombrero Reef and the new northwest Florida Bay station. The former would address flows in Hawk Channel and the latter would address the inflow to the Bay from the southwest Florida Shelf. All participants agreed that this would be a superb idea and that obtaining additional real-time data would be very valuable particularly to those planning studies of biological, chemical, and physical processes.

At this point in the discussion, a question arose as to how "real-time" the hydro-dynamic model would be, and could it incorporate such real-time measurements. It was explained that the model is not being designed for real-time operations but for running scenarios to test alternative water release options. However, it might be possible and desirable for managers to use a more developed and user-friendly version in the future for pseudo real-time assessments within the Bay. Future torquing of the model for this purpose was thought to be a real possibility once it is operational and is in the hands of its likely users (SFWMD, DEP and others).

Drifters were agreed to be essential supplements to fixed station measurements of currents and water properties. Because of the high variability seen in drifter deployments in and around Florida Bay, however, it was suggested that additional drogue-tracking experiments are necessary in western and northwestern Florida Bay as well as off the Dry Tortugas. Rather than requiring individual investigators to make special cruises for the purpose of releasing these drifters, the drifters could be released either by other researchers working in western Florida Bay or staff from the Keys Marine Laboratory charged with servicing the SEAKEYS stations.

There is a definite need for smaller-scale, process-oriented studies of advection/disperison within the Bay. With the exception of one or two studies conducted by Ned Smith, little direct information is available regarding exchange rates between basins and through interior passes. Originally, a suggestion was made to use dye as a tracer; however, given its high visibility and local environmental sensibilities the use of less obvious chemical tracers would be preferable. A possible candidate would be the gas sulfur-hexafluoride (SF-6) with which groups in Miami and Tampa are already familiar. A further advantage is that SF-6 can be detected at considerably lower concentrations than the dyes commonly employed.

Several scientists felt that exchanges between Hawk Channel (see earlier SEAKEYS section) and Florida Bay and those at the western boundary have been inadequately resolved and that additional data is needed to better delineate these important processes. While drifter measurements (discussed above) will contribute, Eulerian data is also required. Given that the western boundary encompasses a distance of 40 km, the previous (3 current meter) and present (1 current meter) station distribution appears inadequate. Moreover, preliminary analyses suggest that there are significant differences between the results obtained at these locations indicating a complex dynamic western boundary. Participants felt additional current meter deployments to measure flow on the western boundary are essential to model verification. The western boundary may be an important site for nutrient exchange and is, therefore, a particularly appropriate locale for coupled physical/chemical/biological studies. In addition, the potential impact of Florida Bay waters upon the FKNMS reef tract cannot be evaluated without additional biological/chemical/physical sampling near the inlets controlling exchange between Hawk Channel and Florida Bay.

In general, very little is known about the impact of storm events on Florida Bay. Two recommendations were made on this topic. The first recommendation was that the scientific community needs to take a better look at water properties immediately after frontal passages (aerial mapping of salinity could help, if it works). The second recommendation was that the physical research community must be prepared so that if a major storm impacts the Bay, we are ready to respond and investigate post-storm conditions. This will require considerable flexibility not only by the researchers but also their program managers. Some questioned whether the circulation model would be able to incorporate storm conditions, but the Army Corps of Engineers (ACoE) participant stated that in other applications the model formulation currently in use had readily done this and could do so again if required in Florida Bay.

A discussion took place regarding the need for detailed wind fields over the Bay. Based on several observations, the wind field appears to be relatively consistent. However, it was felt that the data might have been collected from regions that are too close for a truly accurate assessment. The general consensus here was that, at a minimum, the current data should be better analyzed to assess whether a more detailed data set is required. Further, the NOAA scientists who prepare analytical wind fields during tropical storms should be encouraged to do so at other times and make the outputs available to the research community.

Participants supported the general need to maintain a Florida Bay Program web site to assure that raw data and project metadata are disseminated more effectively throughout the scientific and management community. Moreover, biological and chemical processes studies can be targeted (and results put in their proper context) only if near real-time physical characterization data are available. It should be much easier than it is to find out exactly who is doing what and where and to exchange data and model results amongst relevant researchers. We endorse the present plan that one agency maintain, on behalf of the interagency effort, a central web site. This should include not only general information such as the present Strategic Science Plan, the PMC composition and basic charge, the various PMC sponsored workshop reports, and the Oversight Panel reports to the PMC, but also all the appropriate links to individual agency web sites. These additional links would provide information about each agency's projects and access to their data (in some cases by providing appropriate contact points, in other cases direct access). Moreover, all agreed that it will be necessary to establish a list of topical links so that the appropriate information is readily available in a logical and meaningful way independent of what agency is maintaining that data or where the site resides. Specific examples included freshwater discharge data, maps of salinity distribution, chlorophyll concentration (bloom distribution), nutrient concentrations, etc. All these variables can change comparatively rapidly so access to near real-time data is essential to guide field workers. Further recommendations should be sought for the list of topics and how data will be linked to make access as transparent as possible to all users from the other research teams.

At this time, it is not entirely clear where the main web site for South Florida Ecosystem Research (SFER) will be or who will assume responsibility for it. Under the sponsorship of NOAA/NOS/ORCA, Florida Marine Research Institute (FMRI) was attempting to establish an overall metadata data set for the South Florida coastal ecosystem. It is not clear, however, if they will be continuing the project or if another agency is going to take over. Also, there may be other agencies or groups doing the same thing for all the diverse SFER science efforts. It is possible that a federal agency such as the USGS (or others) could develop this metadata database and then hand it over to a state or regional agency like FMRI (or the SFWMD) to administer. The participants felt this to be the most likely and desirable process. Independent of who takes the lead on database development, all participants agreed that this should be a priority. It is not a simple process and will need to be done well. For the long-term, participants endorsed a more ambitious goal i.e. a true distributed database accessible through a central web site (much like the U.S. Joint Global Ocean Flux program [JGOFS] maintains). On the other hand, they recognized that JGOFS receives $300 - $500K per year to link all its data sites and maintain a central facility. It also has several full-time employees devoted to the effort. Nevertheless, since they have already developed software for a central site, as well as linking and visualization products, we might profit from their example.

Results of the earlier Model Integration Workshop were discussed and while no written report was available, the various tabular and graphical products developed there were put forward. Additions were made to the only two tables to which we thought we had something to contribute, "Exchanges among models (model areas) of the Florida Bay Environmental Modeling Program" and "Landscape scale variables and external inputs to the Florida Bay Environmental Modeling Program." Regarding "Exchanges among models…" we added tracers and parameter distribution/fields as variables exchanged between the Water Quality Model and the Physical Model and total suspended solids and source areas as variables exchanged between the Sediment Model and the Physical Model. Regarding "Landscape scale variables…" spatial vegetation was suggested as a landscape variable relevant to the Physical Model and surface heat flux, sea level, temperature, salinity, bathymetry, and transport were suggested as external inputs necessary to the Physical Model. All found the exercise dissatisfying and the other tabular and graphic products more confusing than illuminating. Nevertheless, various related and important points arose during our discussion, and they are summarized below.

We recognized that measurements of water quality parameters are essential to verify water quality models (and provide input to ecological models) and, as passive tracers, could validate hydrodynamic models as well. A water quality model is unlikely, however, to rigorously address the issue of sediment transport. In fact, no dynamic sediment transport model is currently under development. There are two reasons for this. First, because the effort required would be intense, and it is not clear that there is a strong need for such a model in the restoration context. Second, because we do not yet have even a conceptual model of the re-suspension process underlying sediment transport given the complexities of biologic influences within the Bay (e.g. algal mats). Contrary to our hopes, no simple relationship has emerged between bottom type and susceptibility to re-suspension. In any case, bottom characteristics will be useful in other contexts. For example, bottom friction depends upon vegetation type and density, which implies an obvious feedback between ecological models and physical modeling exercises.

Several discussions occurred regarding large-scale physical modeling efforts, and we were pleased to learn that NOAA regional circulation model outputs are currently in use by the AcoE. All agreed that we would like to see the verification results of the Hydrodynamic Model as soon as possible. Since several of the participants were assisting in the verification process, we were assured that they would be among the first to whom the results were distributed. There are several other models available if the ACoE’s model is unsuccessful. Unfortunately, none of these models are at the point where actual comparisons between model results are possible unless further time and money is put into their development. Until the results of the ACoE model are made public, no further effort on these other models is warranted. The AcoE did offer to distribute a preliminary report from the hydrodynamic modeling effort to the PST since the final report is not due until next year. While we have no reason to think the ACoE model will not suffice (and its resolution appears to well surpass what we perceive as the requirements of understanding water quality and ecological parameter distribution), until it is verified and distributed to the user community, this cannot be assured.

We did not directly discuss the issue of water quality modeling since the participants did not feel qualified to assess what sort of water quality model was needed (or if one was needed at all). In regard to integrated model development (and system understanding), the participants felt that in comparison to the ecological and chemical programs, the Interagency physical program is relatively mature and proceeding well.

In summary, the participants at the workshop felt that it was a productive, useful, and enjoyable exercise and, before adjourning, agreed to hold another PST meeting sometime in the Spring prior to the annual Florida Bay Science Conference.

AGENDA

PMC Members and Organizers: Peter Ortner, Ellen Prager, DawnMarie Welcher

Physical Science Team Leader: Tom Lee

Participants: Frank Aikman, Sandra Vargo, Mike Choate, John Wang, Libby Johns, Paul Willis, Mark Luther, Doug Wilson, Bill O'Connor, Hugh Willoughby, Eduardo Patino, DeWitt Smith, Ned Smith, Peter Swart