a. Renewable Land Resources 



A 2-frequency (C + L) and 2-incidence angle (20° + 50°) 

 system will meet most of the wide variety of applications 

 required for agriculture, forestry, and hydrology. 

 Operation as a 4-band system, i.e., C-band at 20° + 50°, 

 and L-band at 20° + 50°, providing simultaneous data 

 acquisition, is desirable but not mandatory. The second 

 most desirable is a C- + L-band system at 45° or higher 

 incidence angle; a C-band system having two incidence 

 angles of 20° + 50° is the third choice. It should be 

 noted that the above are preferred systems; carefully 

 selected single-frequency/ single-incidence angle system 

 would still provide much useful data. 



b. Nonrenewable Resources 



The probability of C-band providing better textural and 

 soil moisture discrimination makes it a first choice for 

 geological applications, although at this time, L-band 

 appears to be acceptable. The extraction of geological 

 information from radar images is greatly facilitated by 

 viewing the Earth's surface in stereo. Although a stereo 

 image can be created by imaging the terrain from opposite 

 directions, the most effective stereo models have been 

 achieved with images that have the same look direction, 

 but a difference in incidence angle of between 15 and 

 30°. There is a requirement therefore, for continuous 

 recording of the same terrain at two different incidence 

 angles during adjacent, parallel orbits. A C-band system 

 having two incidence angles of 30° + 50° is optimum, 



c. Ice 



A large number of different ice parameters must be 

 monitored. Only a few sets of simultaneously recorded C- 

 and L-band images of ice have been made available to the 

 Ice Team for study. However, based on analysis of image 

 interpretability, a C-band system is preferred; L-band is 

 acceptable. Incidence angle does not appear to be 

 critical and could range from 40° to 50° for optimum 

 performance. Should a tradeoff for increased swath width 

 be possible, incidence angles as low as 35° are 

 acceptable. 



d. Oceans 



A C-band frequency is preferred at an incidence angle of 

 between 25° and 35°; L-band is marginally acceptable at 

 the same (25° to 35°) incidence angle. 



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