from those cited in that the original daily temperatures 

 are used in the analysis without a preliminary smoothing 

 by monthly averaging. 



The purpose of time-series analysis is to isolate 

 trend, oscillation, and random elements, which are 

 defined as follows. Trend is a gradual increase or decrease 

 in a system over a long period of time; an oscillation is a 

 variation about the trend that occurs with more or less 

 regularity over some time interval; and a random element 

 is an unpredictable variation in the variable. If long term 

 trend does not exist, then the primary need is the statistical 

 fitting of some function to time series to represent the 

 oscillatory element. 



Several sets of daily sea-surface temperatures have 

 been examined. Measurements were made at the two open 

 ocean and four island or coastal locations shown in figure 1 . 

 To indicate how individual temperature measurements vary 

 throughout the year, one year of measurements for each 

 location is presented in figure 2. These years of tempera- 

 tures are taken from records that vary in length from 7 to 

 40 years. Pertinent information about the stations yielding 

 these records are included in table 1. 



