|Remote Sensing for Coastal Management|
Remote sensing is the science of obtaining information about objects or areas from a distance, typically from aircraft or satellites. In order to take a snapshot of the entire Bay essentially all at one time, remote-sensing technologies must be used. NOAA collects and uses remotely sensed data for a range of activities, including mapping coastlines and assessing water quality parameters, such as chlorophyll-a and temperature. Because temperature and chlorophyll levels can define fish habitats, information obtained via remote sensing is used in fisheries modeling efforts.
How Do Satellites Track What Is Going on in the Water of the Bay?
Satellite-based sensors can detect subtle changes in ocean color. Changes in ocean color can be caused by varying amounts of chlorophyll, the photosynthetic pigment that is found in all plants, including phytoplankton. The satellite measures the light intensity reflected off the ocean's surface at several wavelengths. Algorithms are applied to the data to discriminate between changes in color caused by chlorophyll, sediments, and other substances in the water.
NOAA's CoastWatch Program provides near-real-time oceanographic satellite data to federal, state, and local marine scientists, coastal resource managers, and the general public. The CoastWatch East Coast Node, located at the NOAA Chesapeake Bay Office, provides data and value-added products including near-real-time imagery of chlorophyll-a, water clarity, surface temperature, and winds specifically for the East Coast from Maine to Florida.
Remote-sensing technologies are continually evolving and changing, and coastal managers are finding new ways to use this technology, including assessing water quality, land cover, and change, and in developing forecasts of harmful algal blooms and predicting the likelihood of where sea nettles (jellyfish) exist in the Bay.
Sea nettles, Chrysaora quinquecirrha, seasonally infest the Chesapeake Bay and affect many activities on the Bay, including swimming and boating. Maps of probable sea nettle presence are created by using data from hydrodynamic computer models and remote-sensing observations from NOAA satellites to identify locations where the current environmental conditions are favorable to sea nettles.