necessary that a 1-2 day revisit interval be specified. It would be most cost 

 effective to investigate the question of needed revisit intervals through 

 simulations of spacecraft SAR data and truck-based experiments instead of 

 through use of actual spacecraft SAR data acquired every day. The same is 

 true for snow applications as well, where the optimum revisit interval is 

 probably less than the 10-day revisit interval recommended here for the 

 research satellite. 



2-6 



