5.5 NAVIGATIONAL ACCURACY 



Location of pixels in latitude-longitude coordinates is important for 

 quantative scientific use of color scanner data. In order to make these 

 data useful for other than individual scene analyses, the scientist must be 

 able to use observations from many passes to generate a time series and do 

 statistical analysis. This implies that location accuracy of data from 

 different passes must be sufficiently precise to allow compositing. For 

 these purposes, an absolute navigational accuracy of 10 km for high resolu- 

 tion local data and 25 km for low resolution global data is required. 



5.6 DATA DELIVERY 



The details of data processing and delivery are complex and are discussed 

 in more detail later in Appendix C. For purposes of an overall require- 

 ment, the OCSWG considers satisfactory data processing and delivery to be 

 the most vital concerns that the ocean science community have for a new 

 satellite observing system. History of other ocean-oriented satellite 

 data systems has not been encouraging in this respect. Timeliness of data 

 processing is most important in that if data processing time does not keep 

 pace with the data flow, backlogs quickly develop and it can become 

 literally years before the data are made available to the research commu- 

 nity. In that case the data are often not widely used by scientists and a 

 multi-million-dollar satellite is under utilized. Further, satellite 

 pictures by themselves are not satisfactory for quantative ocean study, 

 but the observations must be presented as quantative, navigated values of 

 chlorophyll and diffuse attenuation coefficient. To this end, the data 

 available to the user must meet the following requirements: 



a. For near real-time positioning of ships during MAREX field 

 experiments, quick-look data must be available within 24 hours of 

 observation or direct satellite read-out for user ground stations 

 must be available in selectable areas worldwide. 



b. For integration with cruise results, fully processed high-resolu- 

 tion data must be available to the user within 30 days of observa- 

 tion. This is "Level II" processing which means cloud removed, 



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