Latitudinal Variation 



The observations used to examine the latitudinal variation in 

 sea-surface temperature were taken from Punched Card Deck 116, 



U. S. Merchant Marine and Other Ship Observations, 1949 , 



of the National Weather Records Center, These are marine 

 weather observations which include, among other parameters 

 measured, a sea-water temperature. These observations are 

 usually taken by a mercury-in-glass thermometer installed in 

 the ship's sea-water-intake system and are reported to the nearest 

 whole degree Fahrenheit. 13 Listings of all weather observations 

 made in the North Pacific north of 20 N for the years 1956 and 

 1957 were obtained from the Records Center. 



From the punched-card deck the sea-surface temperatures 

 taken north of 20 N and along a given longitude, ±0. 2 of longitude, 

 were selected to examine the variation of surface temperature as 

 a function of latitude. The longitude strips selected were: 126 , 

 129°, 132°, 135°, 138°, and 141° W. The data from three of these 

 strips for March and September 1956 and 1957 are plotted in 

 figure 2. March and September were used to minimize the effect 

 of the seasonal change in temperature. 



21 



