I. IKTRODUCTIOS 



In connection vith the deTelopment of an oceanographlc prediction 

 system (ASWEPS), the ^ydrographic Office is currently preparing exper- 

 iBiental sea surface temperature charts* These charts cover a small 

 area of the western North Atlantic and are prepared for periods of 1, 

 10, and 30 days. Sea svtrface temperature analytic techniques and theo- 

 ry are discussed in the following sections. 



The isotherms of long-term mean sea surface temperature charts are 

 generally west-east oriented with valties increasing toward lower lati- 

 tudes. In these respects, they resemble mean isoharic patterns derived 

 from large-scale migratory atmospheric systems. >!6reover, apparent 

 agreement between orientation of mean isobars and resultant ocean cur- 

 rent drift suggests that water temperatures may be related to wind-driv- 

 en currents. Since the patterns of mean charts depend only on resultant 

 values averaged over specified unit areas, they do not necessarily rep- 

 resent the true nature of a given field. This would be especially true 

 if the systems comprising a particular field were narrow, elongated bands 

 separated by sharp gradient zones (Figure la), and the dimensions of the 

 unit areas on which mean charts are based were relatively large when com- 

 pared to the width of the systems (Figure lb). 



a ASSUMED STABLE CURRENT PATTERN 

 IN ADJOINING ONE-DEGREE 

 I QUADRANGLES 



FIGURE 



b MEAN TEMPERATURES DEDUCED FROM 

 DATA !N THE ABOVE QUADRANGLES 



POSSIBLE MISREPRESENTATION OF A STABLE 

 TEMPERATURE FIELD BY MEAN CHARTS 



