SALINITY %o 



Figure 8. — Temperature-salinity diagram for day 244 (1 September 

 1969) based on original isentropic data (o) with temperature-salinit\- 

 values from the harmonic fit (x). The numerals give the depth in 

 meters for the original isentropic data. The numbers in parentheses 

 represent the difference between the depth of the original isentropic 

 values and those from the harmonic fit. 



original isentropic data. For 1 July 1971 the expected 

 isentropic values showed no inversions, but the com- 

 parison was made by deleting the u, 24.0 and a^ 24.2 

 levels at 3 and 9 m, respectively, giving a mean 

 temperature of 15.31 °C, which was identical with that 

 calculated from the original isentropic data and com- 

 pared with 15.25°C before the data were deleted. 



Sampling Gaps 



Figure 1 shows that there were gaps lasting up to 

 several months in the oceanographic data series. From 

 1966 to the winter of 1968 oceanographic stations at 

 OWS-V were occupied only on alternate Coast Guard 

 patrols. Subsequent to this time there were gaps of up to 



SALINITY %o 



Figure 9. — Temperature-salinity diagram for day 182 (I July 1971) 

 based on original isentropic data (o) with temperature-salinity values 

 from the harmonic fit (x). The numerals give the depth in meters for 

 the original isentropic data. The numbers in parentheses represent 

 the difference between the depth of the original isentropic values 

 and those from the harmonic fit. 



3 wk in the series. The data gaps were bridged by linear 

 interpolation, as previously described, solely to facilitate 

 the analysis procedure. Therefore, although Equation (3) 

 will provide interpolated values for the gaps, the 

 significance of such values is limited. The limitation is 

 related to the Nyquist frequency, 



/ 



1 



2At 



n 

 T 



(6) 



specifying the highest harmonic to which, in theory, 

 Fourier analysis can be carried out when the data inter- 

 val is St (Jenkins and Watts 1968). Thus, with It = 

 T/2n, the longest 1966 data gap of about 40 days permits 

 interpolation if the summation in Equation (4) is carried 

 out to M = 4. The longest 1967 gap of about 60 days limits 

 meaningful summation in Equation (4) to n = 3. 



The gap between day 325 of 1967 and day 55 of 1968 

 comprised almost 90 days. Again, in order to facilitate 

 the analysis procedure the values for day 60 of 1968 were 



12 



