1. INTRODUCTION 

 1. 1 The Importance of Sea Surface Temperature Data 



The need for accurate measurement of the sea surface temperature (hereafter 

 referred to as SST),on a daily basis and for large areas of the world's oceans, is 

 becoming increasingly acute. Nearly all of man's sea-oriented activities (such as 

 fisheries, navigation, marine weather forecasting, and naval operations) rely to 

 some extent upon knowledge of the SST patterns and their variation with time. 



Prediction of the spawning grounds of certain varieties of fish can be made using 

 accurate SST infornn.ation, while good fishing areas frequently occur at the confluence 

 of oceanic currents which can in turn be detected by the packing of sea surface 



isotherms. Determinations of the probability of icing or fog formation, require 



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 SST data. Various investigators ' ' have demonstrated direct correlations 



between the SST and such meteorological phenomena as the growth and travel of 



hurricanes , and extratropical cyclonic development. The SST can be related to the 



subsurface temperature structure, which in turn affects the propagation of sound, 



a significant parameter in submarine warfare. 



Despite the importance of SST data, this quantity is generally known only in a 



gross climatological sense, and even then not adequately over all the oceans of the 



world. Temperature distributions and their variations on the time and space scales 



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 required for the needs outlined above are far less well determined. 



1. 2 Use of Satellite Measurements 



As indicated above, the theory and techniques which can make practical use of 



greatly improved SST information are at hand; what is lacking is an adequate amount 



of data. A satellite equipped with IR sensors is a world wide observing tool which 



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 may be used to considerably close this "data gap". This first study of the feasibility 



of such an approach employed principally the Channel 2 (8-12 micron) radiometer 



data from the TIROS VII meteorological satellite. A polar orbiting, sun-synchronous 



satellite such as Nimbus, which could provide daily coverage of all the earth's oceans, 



can drastically inniprove the capabilities demonstrated in this study. While the 



Nimbus I HRIR (3. 7\j.) has serious limitations for this application (see Section 3. 1), 



the Nimbus C MRIR should be an improvement over the TIROS data in many respects, 



including coverage, sensitivity, calibration, and atmospheric attenuation. 



