Click On Any Region
IRIS_areas_map Mississippi River Region Mobile Bay Region Florida Big Bend Region Central West Florida Region Florida Keys Region South East Florida Region
You will be redirected to the data for that station.

   IRIS Clickable Map

Red tides or harmful algal blooms (HABs) of the toxic Karenia brevis occur in the Gulf of Mexico nearly every year, and it is important to know the location, intensity, size, and potential transport pathways of red tides in a timely fashion so that governmental agencies and other groups as well as the general public can be better informed.

The IRIS is designed for this purpose. It integrates satellite observations, numerical models, and water sampling to provide information on the location, intensity, spatial extent, and surface transport of red tides and other types of discolored waters. The information is updated daily through a user-friendly web portal, where a user can bring all data layers to Google Earth to navigate and to add other data layers. The example below shows the integrated three data layers in Google Earth.

Three data layers are used in the IRIS: satellite remote sensing, numerical modeling, and water sample analysis. You can learn about these data by clicking the tabs at the top.

An Example of How IRIS Works
How Iris Works
Click the "Putting it Together" tab above to see how it these data are integrated. Further details can also be found in Hu et al. (2016).

The IRIS is a result of collaborations between USF College of Marine Science and the Florida Fish and Wildlife Research Institute, with financial support provided by the state of Florida, NASA, NOAA, ONR, and other agencies.

   IRIS Clickable Map

Satellite data currently include those collected by NASA’s MODIS/Terra (2000 – present), MODIS/Aqua (2002 – present), and NOAA’s VIIRS (2012 – present). The raw data are obtained from NASA every day within 4-6 hours of the satellite overpass, and then processed using both NASA standard and community accepted algorithms tailored for coastal waters and algal blooms to generate a suite of imagery data products (Hu et al., 2004).

Of these, the most relevant imagery types are the normalized fluorescence line height (nFLH) and enhanced Red-Green-Blue ERGB), which are used to detect algal blooms and discolored waters (see images below), respectively (Hu et al., 2005).

MODIS nFLH and ERGB Image Examples
MODIS nFLH image and ERGB image show algal bloom off Tampa Bay (A) and discolored water along the entire west coast of Florida down to almost Charlotte Harbor (B). The warm colors (yellow-red outlined in circle) in the nFLH image indicate high concentrations of algae; the dark color in the ERGB image is a result of light absorption by colored dissolved organic matter (CDOM) and algae.

   IRIS Clickable Map

Numerical models provide ocean currents to track red tides, and the results come from two sources. For the west Florida Shelf, results come from the West Florida Coastal Ocean Model (WFCOM, Zheng and Weisberg, 2012) which accounts for both local and deep-ocean forcing by nesting the Finite Volume Coastal Ocean Model (FVCOM Chen et al., 2003) into the Hybrid Coordinate Ocean Model (HYCOM, Chassisgnet et al., 2009) and adding eight principal tidal constituents along the open boundary. For other regions, results come from the HYCOM consortium. The image below shows an example of the WFCOM surface current and salinity data product.

Virtual Antenna Web Interface
Numerical Model
An example of the WFCOM nowcast-forecast modeled surface ocean velocity and salinity. Near real-time and historical products are available at

   IRIS Clickable Map

Field data come from the Florida Fish and Wildlife Research Institute (FWRI), which has collected data either routinely (i.e., weekly, twice-monthly, monthly) or in response to bloom events (Heil and Steidinger, 2008). Data used in the IRIS include the cell concentrations of the Karenia brevis dinoflagellate determined from water samples. K. brevis is the marine organism mostly responsible for red tides (HABs) in the Gulf of Mexico (; The figure below shows examples of the water sample analysis results.

Karenia Brevis Abundance
Water Sample
Maps showing sampling efforts and Karenia brevis abundance during July-September 2014 (left) and March-May 2014 (right). Current status maps are posted on the state’s website (, weekly and archived maps are available in a Flickr gallery (

   IRIS Clickable Map

Satellite imagery and numerical modeling results are updated daily, while water sample analysis results are updated weekly (usually on Fridays). They are pulled together automatically through a computer program and made available online in near real-time, with full Google-Earth Compatibility. The example below shows the three data layers integrated in Google Earth.

To see an example showing how IRIS works, click the "What is IRIS?" tab above or see the image here: ("What is IRIS?"). Further details can also be found in Hu et al. (2016).

Where to find the data

At the top of each tab on this page, there is a clickable map that will take you to the region you are interested in. Click the "IRIS Clickable Map" button, and click on the region. If you mouseover the regions, you will see what we call them. You may also access the data in the menu to the left, click on the “Satellite Data Products” tab to select the area of interest. The figure below shows an example of the web interface, where the areas are listed to the left.

Main Satellite Pass View
Satellite Pass View
IRIS Web layout where the area of interest, date, satellite pass, and image type can be selected and brought to Google Earth together with other data

Click on the area of interest (for example, “Big Bend FL”), the most current images (either today or yesterday depending on the web access time) are displayed as image icons. The individual satellite passes are listed on the top, and the day of interest can be selected from the calendar to the left. Click on a satellite pass, the image icons for the pass are displayed. An “Animate” button can be clicked to select the image type and period to animate a sequence in order to determine the date(s) of interest. A mouse click on the image icon will bring a full-resolution image to a new browser window, and a mouse click on the GE symbol Google Earth below the image icon (in a red box in the above picture) will bring all 3 data layers (the image itself, corresponding surface currents, and red tide cell concentration) in Google Earth if Google Earth is installed on the user’s computer.

Multiple images can be brought into the same Google Earth in the same way. Note that currently red tide cell concentration data are available only for the eastern Gulf of Mexico.

Once in Google Earth, all three data layers can be turned on/off through the GE menu to the left (see example below). A mouse click on a current vector (arrow) or a water sample location (balloon) will bring a pop up window to show detailed information. This can be seen in the image in the first tab click here: ("What is IRIS?")

Google Earth View
Google Earth View
Result of a mouse click on the GE symbol under an image icon, where all three data layers (satellite image, surface current vectors, and water sampling results) are brought in Google Earth at the same time

While the IRIS provides integrated information on red tide location, size, and its potential trajectory, near real-time prediction of red tide trajectories have been implemented through a partnership between the FWC and USF, where more information can be found through

  IRIS Clickable Map

Chen, C., H. Liu, and R. C. Beardsley (2003). An Unstructured Grid, Finite-Volume, Three-Dimensional, Primitive Equations Ocean Model: Application to Coastal Ocean and Estuaries. Journal of Atmospheric and Oceanic Technology, 20:159-186.

Heil, C. A., and K. A. Steidinger (2008). Monitoring, management, and mitigation of Karenia blooms in the eastern Gulf of Mexico. Harmful Algae, 8:611-617.

Hu, C., F. E. Muller-Karger, C. Taylor, K. L. Carder, C. Kelble, E. Johns, and C. Heil (2005). Red tide detection and tracing using MODIS fluorescence data: A regional example in SW Florida coastal waters. Remote Sens. Environ., 97:311–321.

Hu, C., B. B. Barnes, B. Murch, and P. Carlson (2014). Satellite-based virtual buoy system (VBS) to monitor coastal water quality. Optical Engineering. 53(5), 051402. DOI:

Hu, C., B. B. Barnes, L. Qi, and A. A. Corcoran (2015). A harmful algal bloom of Karenia brevis in the northeastern Gulf of Mexico as revealed by MODIS and VIIRS: A comparison. Sensors, 15:2873-2887, doi:10.3390/s150202873.

Hardy, R. F. (2014). Assessment of surface-pelagic drifting communities and behavior of early juvenile sea turtles in the Northern Gulf of Mexico. MS Thesis, University of South Florida, 118pp.

Hu, C (2009), A novel ocean color index to detect floating algae in the global oceans, Remote Sens. Environ., 113, 2118–2129.

Hu, C., B. B. Barnes, B. Murch, and P. Carlson (2014), Satellite-based virtual buoy system (VBS) to monitor coastal water quality, Optical Engineering, 53, 051402. doi: 10.1117/1.OE.53.5.051402.

Hu, C., B. B. Barnes, L. Qi, and A. A. Corcoran (2015). A harmful algal bloom of Karenia brevis in the northeastern Gulf of Mexico as revealed by MODIS and VIIRS: A comparison. Sensors, 15:2873-2887, doi:10.3390/s150202873.

Hu, C., B. Murch, A. A. Corcoran, L. Zheng, B. B. Barnes, R. H. Weisberg, K. Atwood, J. M. Lenes (2016). Developing a smart semantic web with linked data and models for near real-time monitoring of red tides in the eastern Gulf of Mexico. IEEE Systems Journal, 10:1282 - 1290. doi:10.1109/JSYST.2015.2440782

Zheng, L., and R. H. Weisberg (2012). Modeling the west Florida coastal ocean by downscaling from the deep ocean, across the continental shelf and into the estuaries. Ocean Modelling, 48:10-29. (integrated red tide information system) (FWRI current and past red tide status)

http:// (Same FWRI red tide status in Facebook) (numerical ocean modeling using WFCOM and other tools) (HYCOM consortium to provide global ocean modeling data) (red tide trajectory forecast)