of ice features can be expected in a given season at a given location? What 

 is the impact of ice cover information on global weather forecasting? Also, 

 as precise forecasting of ice conditions is important in polar operations, 

 there is a particular need to improve the accuracy of short-term, 1-5 day, ice 

 response forecasts. Summary information requirements for research in 

 operations and engineering are presented in Table 1. 



In general, researchers involved with operational problems need accuracy 

 in different areas than do researchers involved with science. For example, 

 the computation of fluxes between the ocean and the atmosphere requires rather 

 detailed knowledge of the ice thickness distribution with an emphasis on the 

 accurate measurement of the areal fractions of thinner ice and open water. 

 The operations problem, on the other hand, is primarily concerned with the 

 exact location of thin ice, open water, and heavy ridging. Thus, the 

 calibration needs are different; clearly more of the total operational problem 

 can be more fully accomplished by a simpler, longer wavelength, Seasat-type 

 radar. Such a system, complemented by a wide-swath coarse footprint 

 instrument, such as a scatterometer or radiometer, constitutes the basic 

 requirement for research on sea-ice operational problems. In the context of a 

 spacecraft SAR development program spanning several decades, a simple SAR 

 similar to the Seasat instrument would satisfy short-term operational needs 

 and would also contribute significantly to progress in long-term science 

 goals. However, it appears that these goals would be better met, of course, 

 by shorter wavelength, higher-resolution systems of the future. 



The proposed sea-ice imaging radar program can be summarized as follows. 

 At the soonest possible time, a satellite carrying a Seasat-type Synthetic 

 Aperture Radar (SAR) should be deployed. The SAR system should be augmented 

 by a system or systems that provide areal measurements of ice characteristics, 

 such as a scatterometer or radiometer. Also a data-buoy interrogation system 

 should be deployed. Such a combined system would largely satisfy the research 

 community involved with operational problems and would also enable 

 considerable progress to be made in those areas of sea-ice science concerned 

 with ice dynamics. By the time improvements in SAR technology permit higher 

 frequencies and higher resolutions, the science community should be prepared 

 to exploit these new systems. At the same time, the research community 

 concerned with sea-ice operations problems should be prepared to justify an 

 operational level SAR free-flyer. Thus, part of the recommended program for 

 current consideration is concerned with the implementation of operational- 

 simulation projects involving engineers, scientists, and managers from a 

 variety of agencies and private organizations. These projects would be 

 concerned with actual application exercises such as navigation of an ice- 

 breaking tanker or deployment of a drill ship. This program, centered on the 

 flight of a Seasat-type SAR with supplementary instruments, would provide a 

 valuable scientific data set plus operational experience that could be 

 followed by more sophisticated flight systems with improved capabilities for 

 both science and operations. Such developments would presumably be entirely 

 supported by operational agencies and/or the private sector that is concerned 

 with sea-ice operations. This overall program provides a logical exploitation 

 of techniques for observing sea ice from space for the immediate and longer 

 range future. 



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