402 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



JFMAMJJASOND 

 1955 



JFMAMJJASOND 



1956 



JFMAMJJASOND 

 1957 



JFMAMJ JASOND 

 1958 



Figure 26. — Characteristic heating curve at Koko Head, Oahu, 1956 through 1958. 



chain becomes larger, water will pass through the 

 channels and cold advection becomes apparent. 

 This has the effect of delaying and damping the 

 June-July advection so as to merge it with the 

 October-November period, as is indicated in the 

 advection curve of figure 22B. The advection 

 diagram of area A4 does not exhibit this feature, 

 since it is a combination of diagrams prunarily of 

 the northeast portion of the region, where the June- 

 July advection peak is delayed but not damped 

 out. 



Finally, the characteristic heating curve for 

 Oahu reaches a minimum during December, indi- 

 cating that the December-January advection peak 

 is affecting this area, rather than the delayed 

 February peak to the northeast of the islands. 



Figure 26, showing the rate of change of tem- 

 perature of the Koko Head (Oahu) monitoring 

 station from 1955 through 1958, further illustrates 



the utility of characteristic heating curves. 

 Here the dashed line represents the mean charac- 

 teristic curve discussed above and the solid hne, 

 the observed data. Pronounced deviations from 

 the mean characteristic curve are apparent during 

 1955 and 1957. In 1955, the maximum rate of 

 change of temperature occurred during April and 

 then decreased irregularly to reach its minimum 

 during November-December. The early peak 

 and the generally decreasing trend in the rate of 

 change of temperature are comparable to curves 

 found south of the islands, such as in figure 22A 

 for the three-degree square 14° to 17° N., 156° to 

 159° W. 



Similarly, the shape of the characteristic heating 

 curve in 1957, with a peak 0.4° C. mos."' higher 

 than the mean peak, resembles curves found north 

 of the islands, such as in figure 22C for the three- 

 degree square 26° to 29° N., 156° to 159° W. In 



