How to Read a Satellite Ocean Color Imagery Map

Figure 1. Coastal Zone Scanner Image (CZS) showing discolored water in 1974. Satellite imagery used today is called SeaWIFS

Figure 2. Multi-spectral classified image represented potential "red tide".

Blooms of the toxic dinoflagellate Karenia brevis, formerly Gymnodinium breve, occur periodically throughout the world, but consistently occur in the Gulf of Mexico. These blooms are included in a category of biological events often referred to as "red tides" because their presence discolors the water a reddish-brown hue (Figure 1). The Satellite Ocean Color Imagery Maps compiled by NOAA/NESDIS shown above help in the identification of these blooms and monitoring their presence. Figure 2 represents a multispectral classification used to detect potential K. brevis blooms in ocean color data of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS).

This satellite imagery is currently being tested in an experimental phase to provide vital information to alleviate the impact of these financially debilitating and potentially life-threatening events. The use of satellite ocean color imagery, with its ability to repeat coverages, offers the potential to detect and monitor these biological events at appropriate spatial and temporal scales. However, it must be noted that these maps should be interpreted with caution since the use and analyses of the data are still experimental.