IN SITU MEASUREMENTS OF SMALL ANGLE SCATTERING 

 OF A LIGHT BEAM IN THE SEA 



Dr. Eric J. Softley 

 General Electric Company 



ABSTRACT 



An instrument was designed, constructed, and operated for the 

 measurement of scattering of light in the sea. Particular 

 attention was paid to scattering near the beam axis (small 

 angle scattering). Experiments were run near St. John, V.I., 

 as part of the TEKTITE II Ocean Survey Program. Water samples 

 were taken and analyzed during the experiment. Considerable 

 scattering data were obtained. 



INTRODUCTION 



The design and operation of systems in the sea which depend on optical radi- 

 ation necessitate the need for knowledge about the transmission of energy in 

 the optical band through the sea. This energy, as it propagates, is attenu- 

 ated by scattering and absorption. The scattering, when due to the transmis- 

 sion through a volume of water, is highly dependent on the angle from the 

 initial beam. For a parallel beam of light through an elemental volume dV, the 

 volume scattering, as defined by: 



dPg = gr-C9)PdV 



has the form shown in Figure 1. 



Figure 1. The volume scattering function 

 VII-33 



