II. RENEWABLE RESOURCES MISSION REQUIREMENTS SUMMARY 



Report Based on NASA Renewable Resources 



Study Team Workshop 



Greenbelt, MD 



May 20-21, 1981 



This mission requirements summary, prepared by the U.S. Renewable 

 Resources Study Team, covers (1) the major potential renewable resources 

 applications of L-band (1.275) and/or C-band (5.3 GHz) Synthetic Aperture 

 Radar (SAR) imagery acquired from an orbital free-flying satellite, (2) key 

 radar parameter, specific research issues (e.g., recommended angles, 

 frequencies, or polarizations) which must be addressed in order to specify the 

 SAR satellite mission requirements, and (3) a preliminary specification of the 

 mission requirements for SAR to be used in a future satellite-based research 

 program. Although this document focuses on SAR mission requirements, the 

 philosophy adopted is that SAR imagery is complementary to visible and 

 infrared imagery in the context of potential applications and that both types 

 of imagery must be considered in an eventual mission definition. 



A. POTENTIAL RENEWABLE RESOURCES APPLICATIONS 



The Renewable Resources Study Team has identified four major potential 

 applications of space-borne L-band and/or C-band SAR imagery, which are 

 identified in priority order in Table 2. It should be noted that priority 

 category 4 is a combination of three diverse hydrological applications and 

 that a further subdivision of priorities among these three was not possible. 



The top two potential applications are viewed as of primary importance, 

 and the bottom two are still high priority but of secondary ranking. The 

 highest priority potential applications is the identification, area 

 estimation, and condition assessment for major agricultural crops such as 

 corn, wheat, soybeans, barley, sorghum, rice, cotton, and sunflowers using SAR 

 imagery either alone or in combination with visible/infrared imagery [e.g., 

 Landsat Multispectral Scanner (MSS) or Thematic Mapper (TM)]. The second- 

 ranked potential application is in mapping and monitoring of soil moisture 

 over a wide range of field roughness and vegetative covers, for use in crop 

 growth, yield models, and hydrological models. 



B. KEY RADAR PARAMETER RESEARCH ISSUES 



A mission requirements specification for a SAR satellite must include 

 the desirable f requency(ies ), angle(s) of incidence, polar ization( s ), 

 resolution(s ), and revisit interval(s). Radar parameters of less crucial 

 importance include swath width, dynamic range, registration, etc. The optimum 

 radar parameters must be specified in the context of both SAR and 

 visible/infrared coregistered images; considerations of SAR alone will not 

 allow a meaningful specification of optimum remote sensor system parameters. 



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