OCEANOGRAPHIC CLIMATE OF HAWAIIAN ISLANDS REGION 



395 



1.S- 



1.0 



O 



-IS 



-2.0 



I I I I I I I I I I I I I I I I I 



ADVECTION 



CHANGE OF 

 TEMP. 



HEAT 

 /'~;^ \ EXCHANGE 



a 



1 1 1 1 1 1 1 1 1 1 1 1 1 



1 1 1 1 1 1 1 1 



HEAT EXCHANGE 



/ \ CHANGE OF 

 ' TEMP. 



,.-\. . ADVECTION 



s 



JFMAMJJASONDJFMAM JFMAMJJASONDJFMAM JFMAMJJASONDJFMAM 



Figure 22. — Characteristic advection diagrams for the three-degree squares: A — -14° to 17° N., 156° to 159° W.; B — 20° 

 to 23° N., 156° to 169° W.; and C— 26° to 29° N., 156° to 159° W. 



in December and January. It is also apparent 

 that, during the summer, the change of temper- 

 ature duo to the heat exchange increases northward 

 and, in winter, decreases northward (fig. 17). 



South of the islands the maximum rate of tem- 

 perature increase occurs in April and the maximum 

 rate of decrease occurs in November and Decem- 

 ber. In the vicinity of the islands the time of 

 maximum rate of increase has shifted to June, 

 with the maximum rate of decrease occurring in 

 November and December. To the north of the 

 islands these maxima occm- during May to June 

 and October to November, respectively. Again, 

 there are also changes in the magnitude of these 

 extremes, which is particularly apparent to the 

 north of the islands. 



Ad H 



Together the — and curves indicate advec- 



At pCpZ 



tion and form combinations typical for their 

 location. For example, during May in figiu-e 22B 

 and April in figure 22C, the two curves are super- 

 imposed or in phase for a brief period of time. 

 This means that 



H _Ae 



pCpZ At 



and thai there is no advection. 



At other times, the heat exchange curve can 

 be either above or below the temperature-change 

 or heating curve, indicating either positive or 

 negative advection, respectively. Positive advec- 

 tion means that colder water, and negative advec- 

 tion that warmer water, is mo\'ing into the area. 

 In figure 22A and B, negative or warm advection 

 occurs from March to Maj' and positive, or cold 

 advection, during the remainder of the j'ear. This 



