Sensors 



Multiband Camera : The MSA aircraft is equipped with a nadir- 

 directed 9-lens Itek camera (Toy et al., 1966). This camera simultane- 

 ously photographs nine contiguous, narrow bandwidths between approxi- 

 mately O.360 and 0.900 microns. Optimum f stops are possible in each 

 band, and objects with the slightest differences in reflective spectra 

 are discernible. The camera has a focal-plane shutter and nine 15-cm, 

 Leity, high- re solution lenses with 21° square fields of view. Gelatin 

 filters are used with each lens. Both cameras were used to relate a 

 dye experiment to mass transport. 



Color Camera : A Wild-Heerbrugg RC-8 camera is also used 

 (Toy et al., 1966). This nadir-directed unit obtains color photographs 

 in the infrared region. The system has a 15-cm Aviagon lens cone with 

 a resolution of 50 lines/mm in the center of the field and approxi- 

 mately 25 lines/mm in the corners. Exposure time is continuously vari- 

 able from l/lOO to 1/700 second at f stops of 5.6, 6.3, 8, 11, and l6. 



Infrared Scanner : The Reconofax IV infrared scanner on the 

 NASA aircraft, manufactured by HRB Singer, Inc., is a passive, single- 

 channel system that measures radiation in the 7*3- to 13.5-micron 

 region. Radiation from the ocean surface is reflected by a scanning 

 mirror onto a detector. The detector converts the radiation to an 

 electrical signal, which modulates the intensity of a lamp. The light 

 from the lamp is swept across a film strip in phase with the radiation 

 scanning mirror. The result is a film strip recording of sea surface 

 temperature based on intensity variations proportional to radiation 

 differences of the ocean. An automatic gain control regulates the 

 absolute intensity of the light source (Harris and Woodbridge, 1962). 



Radar Scatterometer : The Ryan scatterometer measures the 

 radar (13*3 GH Z ) reflective properties of the ocean surface as a 

 function of the angle of incidence of the radiation. Doppler spectra 

 fore and aft of the aircraft are recorded simultaneously on magnetic 

 tape. The spectra are then filtered for a particular angle of inci- 

 dence using multiple-filter spectral analyzers. The reflectance curves 

 obtained are related to surface roughness. The total field of view of 

 the instrument is 120° fore and aft and 3° port and starboard (Toy et 

 al., 1966). 



Passive Microwave System : Passive microwave radiometers 

 that measure sea surface temperature by determining the intensity of 

 electromagnetic radiation are also installed on the aircraft. Four 

 radiometers with frequencies of 9-3, 15«8, 22.2, and 3U.0 GH Z were 

 installed in a radome located in the aircraft nose. The grazing angle 

 of the radiometers can be varied approximately 50° from nadir with 

 either horizontal or vertical polarization. Data are recorded on 

 strip-chart recorders and magnetic tape. 



