7. GENERAL SUMMARY AND CONCLUSIONS 



These studies have clearly demonstrated that the satellite IR data provide 

 good measurements of the gradients of sea surface temperatures. This has been 

 confirmed, in part, by consistency of the IR data for areas of known SST persistence, 

 ■which has given some indication of the validity of the observed SST patterns on single 

 passes. These consistency tests have revealed that larger scale patterns and 

 gradients are easily recognizable and change little from day to day, implying that 

 these patterns are real, and can be accepted -without requiring confirmation from 

 conventional measurements (although such conventional substantiating data would 

 still be desirable as we build up further experience regarding these matters). The 

 tests have also revealed that, -where there is persistence of small scale patterns, 

 they also can be seen on repeated passes. Whether they will always be seen, and 

 whether observed changes in these small scale patterns are real, remains unanswered. 

 The answers can probably come only from finding adequate samples of satellite SST 

 data with concurrent conventional observations, or from the processing and analysis 

 of statistically significant quantities of satellite observed SST data. 



Subsequent investigation aimed at determining the extent of the validity of IR 

 observed small scale patterns will be significantly helped by concurrent ship reports, 

 and it may be that such reports will be indispensable. The Gulf Stream provides an 

 ideal area to observe both mesoscale and synoptic scale changes, and has the greatest 

 density of conventional ship measurements. If significant amounts of "real-time" 

 TIROS IR data were to become available, this would be an obvious area to conduct 

 further studies along these lines; this by itself constitutes a strong justification for 

 routine processing of a full year of such "real-time" data. Otherwise, such invest- 

 igations will be hampered until the Nimbus C MRIR data become available. 



The tendency of the satellite IR temperatures, even when corrected for 

 atmospheric attenuation and sensor degradation, to be significantly cooler than 

 conventionally measured temperatures, indicates the need for an occasional bench- 

 mark to calibrate the data. It also re-emphasizes the already existing need for further 

 investigation of these discrepancies, which have been repeatedly noted in various 

 analyses of the TIROS IR data. Even if one of the previously proposed explanations 

 can be shown to be the answer, there will still remain the need for improved methods 

 for estimating the proper corrections. 



The determination of clear sky areas from the IR data themselves uses the 

 Channel 5 sensor to distinguish cloudy from clear areas, and has the advantage 

 of reducing or eliminating dependence on satellite TV or conventional meteorological 



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