SECKEL and YONG : HARMONIC FUNCTIONS 



suming that temperature and salinity samples 

 are of Koko Head quality, then for a resolution 

 of 1 month, weekly sampling is sufficient. Oc- 

 casionally, however, a scheduled sample is not 

 taken or an erroneous value must be eliminated. 

 In such cases sampling gaps would become too 

 large for the desired resolution. Undesirable 

 sampling gaps can be avoided by doubling the 

 minimum sampling frequency. 



The simplicity and economy of deriving har- 

 monic functions by computer are of practical 

 value, particularly in the analysis of data 

 sampled automatically. By this method large 

 quantities of data can be brought into useful 

 form rapidly. 



The results of this paper, based on manual 

 sampling, are useful in the investigations of 

 changes with a duration of more than 1 month. 

 Automated sampling would broaden the spec- 

 trum and permit analyses of shorter term var- 

 iations such as diurnal changes, changes of tidal 

 period, and other changes with durations of less 

 than 1 month. 



Automated sampling would also improve the 

 quality of data since instruments can be placed 

 in locations where undesirable variability is min- 

 imized and where manual sampling is difficult. 

 At Koko Head, for example, samples are ob- 

 tained from an exposed rock ledge where the 

 island effects on the temperature and salinity 

 are small. At Christmas Island, however, the 

 sampling site is convenient and the best obtain- 

 able for manual sampling, but it is not the best 

 in terms of monitoring open-ocean temperatures. 

 This shortcoming is often also the case when 

 temperatures and salinities are measured at 

 tide stations located in protected bays or harbors. 



The value of regularly monitoring the sea- 

 surface temperatures and salinities has been 

 demonstrated in many instances. For example, 

 empirical relations between Koko Head temper- 

 atures and salinities and the availability of skip- 

 jack tuna to the Hawaiian fishery have been 

 demonstrated (Seckel, 1963). Bjerknes (1969) 

 has shown the relationship between anomalously 

 high equatorial sea-surface temperatures using 

 primarily Canton Island observations, and the 

 intensification of the North Pacific westerlies 



and trades. This relationship must, in turn, 

 affect temperatures and salinities in the North 

 Pacific. 



In view of these factors, serious consideration 

 should be given to the establishment of auto- 

 mated sampling stations at selected islands in 

 the Pacific. The derivation of harmonic func- 

 tions, as demonstrated in this paper, would make 

 reduction of data into usable form simple and 

 economical and so facilitate the study of pro- 

 cesses which govern the climate in both ocean 

 and atmosphere. 



LITERATURE CITED 



Bjerknes, J. 



1969. Atmospheric teleconnections from the equa- 

 torial Pacific. Mon. Weather Rev. 97(3) : 163-172. 



HOLLOWAY, J. LeITH, JR. 



1958. Smoothing and filtering of time series and 

 space fields. Advances in Geophysics 4: 351-389. 

 Academic Press, New York. 

 Kaplan, Wilfrbh). 



1953. Advanced calculus. Addison-Wesley Pub- 

 ishing, Cambridge, Mass., 679 pp. 

 Seckel, Gunter R. 



1962. Atlas of the oceanographic climate of the 

 Hawaiian Islands region. U.S. Fish Wildl. Serv., 

 Fish. Bull. 61: 371-427. 



1963. Climatic parameters and the Hawaiian skip- 

 jack fishery. In H. Rosa, Jr. (editor), Proc. 

 World Sci. Meet. Biol. Tunas Related Species. 

 FAO Fish. Rep. 6, 3: 1201-1208. 



1969. The Hawaiian oceanographic climate, July 

 1963-June 1965. Bull. Jap. Soc. Fish. Oceanogr., 

 Spec. No. (Prof. Uda's Commem. Pap.), pp. 105- 

 114. 

 Seckel, Gunter R., and Kenneth D. Waldron. 



1960. Oceanography and the Hawaiian skipjack 

 fishery. Pac. Fisherman 58(3): 11-13. 

 Sokolnikoff, Ivan S. 



1939. Advanced calculus. McGraw-Hill Book Co., 

 New York and London, 446 pp. 

 Tabata, S. 



1964. A study of the main physical factors gov- 

 erning the oceanographic conditions of station P 

 in the northeast Pacific Ocean. D. So. thesis, 

 Univ. Tokyo, 264 pp., 55 figs., 17 tables, 41 pp. 

 appendixes. 



Wyktki, Klaus. 



1967. The spectrum of ocean turbulence over dist- 

 ances between 40 and 1000 kilometers. Deut. 

 Hydrog. Z. 20(4) : 176-186. 



195 



