Harmful Algal Bloom Forecast Project

Application of Remote Sensing to Red Tide Forecasts in the Gulf of Mexico: Proceedings of a Workshop

Recommendations

A program based on remote sensing methods to track and monitor HAB events is the next step to effectively manage fisheries, public health, and ecosystems related to harmful algae. A remote sensing program provides a mechanism to establish a routine monitoring schedule and to develop a database containing the type, location, frequency, and duration of an HAB. A strategically designed multi-platform, multi-sensor approach is required that will address the prediction, detection, and verification of bloom events (see Table 1). The plan must be flexible to include current capabilities and allow for the incorporation of new capabilities that result from research findings.

Tracking bloom location and monitoring development can be accomplished using ocean color data from several platforms. Satellite coverage will provide large-scale information of offshore phytoplankton biomass changes. Periodic aircraft flights and mooring information can be used to monitor changes nearshore. A method of continuous measurement, as could be provided by OSCR and moorings, would be necessary for an operational predictive capability. Continuous measurements could be limited to strategic areas and times of year to minimize costs.

Areas for Additional Research

Additional research is necessary to develop techniques that can be adapted to remote sensing platforms that would allow G. breve to be quantified as part of the phytoplankton assemblage. Algorithms have been developed to derive chlorophyll a concentration from radiance measurements at selected wavelengths. The ability to quantify G. breve specifically from ocean color requires either additional information that is not available currently by remote sensing methods or the assumption of a monospecific bloom.

Predictive capabilities to detect conditions for bloom development or bloom movements would begin with historical information to generate maps of probable location and timing of HAB events. Trichodesmium spp. blooms have been noticed to precede G. breve blooms and could be used as predictors (Steidinger and Baden 1984; Paerl and Bebout 1988). Trichodesmium spp. offers the advantage of having an optical signal that is different from G. breve and can be distinguished from radiance measurements (Subramaniam and Carpenter 1994; Tassan 1995). The correlation between the presence of physical oceanographic features, such as Loop Current intrusions onto the Florida shelf, and subsequent G. breve events also provides a means to establish a statistical probability for the development of an HAB event.

Research into the causal relationship between physical oceanographic events and subsequent G. breve events would improve the accuracy and precision of predictive models. Monitoring the Loop Current circulation, upwelling events, and wind fields can be accomplished from a satellite platform. The effects of nearshore circulation on bloom movement will require monitoring of winds and oceanographic conditions at a smaller scale to determine mixing rates and bloom trajectories, and to predict landfall. Measurements of this type may best be made using instruments on buoys and drifters.

Steps Toward Implementation

The goal of a comprehensive, cooperative program would be to develop experimental, region-specific forecast systems using remote sensing and all relevant observational and modeling techniques to track the initiation, progress, and demise of HAB.

The objectives would be:

• Foster partnerships between collaborating groups (see Appendix C) including federal and state agencies, academic institutions, and community groups to exchange information and maximize resources.

• Assess potential of remote sensing technologies in combination with in-situ measurements and modeling, to predict, monitor, and track HAB.

• Acquire relevant data for incorporation into model structures.
  • Inventory relevant data sources.
  • Develop tools for the automated acquisition and translation of remote sensing and in-situ data to compatible formats and geo-referencing on a routine basis.
  • Identify areas in which additional investigation or research in remote sensing capabilities or data is required.

• Integrate a wide variety of data types to produce models that increase the accuracy of predicting HAB initiation, movement, intensity, landfall, and demise.
  • Organize and develop a database for point and image data that is compatible with a geographical information system (GIS) and, for accessibility, with World Wide Web-based data fusion tools.
  • Guided by process research, establish empirical and statistical relationships between parameters that increase predictive capabilities.
  • Develop process-based numerical models that use remote sensing data for model forcing and validation. Many of the measurements and modeling efforts currently are supported through the NOAA Coastal Ocean Program’s ECOHAB project.

• Seek additional resources required to bring an operational forecast system on line.

Establishment of this type of project will eventually allow for a forecast capability that is necessary for the development of management and mitigation strategies for rapid response to algal blooms.