The assumed independent variables are latitude, longitude, 

 and day-of-year. A "point, " or "cell," in the model is a 10- 

 minute-by-10-minute area for a 1-day time period. A 10-minute- 

 square area was selected, since the location of the data points is 

 probably not known exactly and the initial interest is in the sea- 

 sonal, or day-to-day, change in temperature. 



Seasonal Variation 



Sea-surface temperature records acquired over approx- 

 imately 96 years were used to establish a functional relationship 

 descriptive of the seasonal variation. The data were for the fol- 

 lowing locations: 



50°N 145°W Pacific Ocean Weather Ship PAPA 



51°50'N 131°W Pacific Ocean St. James Island 



54°10'N 133°W Pacific Ocean Langara Island 



32°50'N IIT^IS'W Pacific Ocean Scripps Pier, La JoUa, Calif. 



35°N 48°W Atlantic Ocean Weather Ship ECHO 



One year of measurement for each location is presented in 

 figure 1 to give the reader some feel for how the individual tem- 

 perature measurements vary throughout the year. A subjective 

 examination of the data shows a more or less regular sinusoidal 

 variation with season. In addition there are variations of a few 

 days' to a few weeks' duration at irregular intervals. At the open- 

 ocean locations, PAPA and ECHO, the shorter-period variations 

 occur less frequently and their magnitude is smaller than at the 



13 



