significant," he continues. "Because 

 you're able to see things in some 

 kind of big picture. That, then, 

 enables you to make decisions in a 

 more realistic context." 



Getting that big picture, ironi- 

 cally, does not come from snapshots 

 from outer space. Satellites like 

 NASA's Landsat do not take 

 photographs, as many believe. 

 Instead, mirrors scan the earth's 

 surface while detectors pick up 

 electronic messages from different 

 wavelengths of light. The satellite 

 translates the messages into numbers 

 and beams the digitized data back to 

 Earth. 



Landsat orbits Earth every 16 

 days, collecting data in 95-by-95- 



Dfli| bi| day, 

 pressure grows on 

 ftie coast's resources. 

 Rs demand for iond 

 and mater rises, 

 so does the need to 

 understand the systems 

 that make up this 

 fragile environment. 

 Satellites can help. 



C.R. Edgerton 



foot segments of land called pixels. 

 One satellite scene includes millions 

 of pixels and covers more than 100 

 square miles. 



For their North Carolina re- 

 search, Khorram and his colleagues 

 buy satellite scenes on tape and feed 

 the digitized data into computers that 

 analyze and display it. 



The first real pictures the re- 

 searchers compose on screen look 

 like color infrared photographs with 

 splotches of red, green, white and 

 blue. But satellites pick up and "see" 

 much more detail. 



On Earth, we see colors in 

 everything around us. Green trees. 

 Blue water. Red birds. Silver fish. 



Colors are actually different 

 wavelengths of light. Each object we 

 see reflects its own signature combi- 

 nation of light on the spectrum. 

 Colors make up the shorter waves. 

 But the mechanical eyes of a satellite 

 such as Landsat can sense longer 

 infrared waves and a thermal, or 

 heat-sensitive, one too. 



Although we see green pines, for 

 example, Landsat reads light reflect- 

 ing from the trees in the green, red, 

 blue and infrared wavelength bands. 

 Computers, in turn, can display most 

 of these bands for scientists to study. 



In 1990 and 1991, Khorram and 

 his associates used this technology to 

 lay a foundation for research in the 

 Albemarle-Pamlico region. 



One of the largest estuarine 

 systems in the nation, the Albemarle- 

 Pamlico watershed covers 23,000 

 square miles of eastern North 

 Carolina. In the past 20 years, it has 

 been plagued with declines in water 

 quality and aquatic vegetation, and 

 increases in algal blooms, turbidity, 

 and fish and shellfish infections. 



A comprehensive study to 

 pinpoint the problems and outline 

 better management plans began in 

 the 1980s. But a big piece was 



Continued 

 COASTWATCH 9 



