Abstract of Formal Presentation: 



While the development of equipment capable of accurately measuring water 

 color and chlorophyll concentrations from orbital altitudes is under way, 

 it is recognized that considerable work, experimentation and time will be 

 involved before reliable working devices can be orbited. 



In the meantime the contributions which existing imaging sensors can make 

 to the detection and assessment of water color changes should be neither 

 underestimated nor overlooked. 



The catalog of Gemini and Apollo 70 mm color photography contains hundreds 

 of images which demonstrate in a most graphic way changes in water color 

 in the open ocean and its shorelines. 



The changes in water color in many of these images are clearly associated 

 with features such as currents, upwelling, sediments, depth variations, 

 changes in bottom composition, and so forth. The value of these images 

 lies in their ability to indicate important oceanographic phenomena, through 

 variations in water color. For this form of interpretation, it is only 

 necessary to detect and record a color change; it is not necessary to be 

 able to measure it accurately in the radiometric sense. 



The natural color film images taken from space which provide the most 

 useful information for oceanographic purposes (through variations in vjater 

 color) depend on blue and green sensitive layers, to record the differences 

 in the ratios of blue and green light in the water. 



However, hardvrare systems currently proposed for orbit do not include imaging 

 sensors operating in spectral bands below 500 mu, in the blue and blue-green 

 region. The degrading effect on the atmosphere on image contrast below 500 mu 

 has been considered to be so severe that images obtained in this spectral 



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