OCEANIC CIRCULATION AND OCEAN-ATMOSPI :; 



ment for aerological data-gathering, 

 was abandoned in September 1967 

 for economy reasons. 



Air-sea data from near-equatorial 

 islands has great importance because 

 the sea temperature in such localities 

 is subject to fluctuations of much 

 greater amplitude than in the ad- 

 jacent trade-wind belts of either 

 hemisphere. As a consequence, the 

 heat supplied from the ocean to the 

 atmosphere near the equator becomes 

 the most variable part of the total 

 tropical ocean-to-atmosphere heat 

 flux, which in turn is the major con- 

 trol of the global atmospheric circu- 

 lation. It is, therefore, logical to 

 expect that ocean temperature fluc- 

 tuations near the equator will influ- 

 ence atmospheric climate outside of 

 tropical latitudes. This action by re- 

 mote control through the global at- 

 mospheric circulation is here referred 

 to as "teleconnections." 



According to preliminary findings, 

 the teleconnections from the Pacific 

 equatorial air-sea rhythms are major 

 factors — perhaps, in many cases, 

 the dominant factor — in creating 

 rhythms of climatic anomalies any- 

 where on the globe. Hence, these 

 teleconnections must be understood 

 before climatic anomalies can be 

 predicted successfully. 



General Characteristics 



The following facts stand out from 

 the Canton Island record. (See Figure 

 IV-4) 



1. Sea temperatures vary over a 

 greater range than air tem- 

 peratures. 



2. In periods of cold ocean the 

 air is warmer than the sea, 

 whereas in periods of warm 

 ocean the air is colder than the 

 sea. 



3. Heavy monthly rainfall occurs 

 only during periods of warm 

 ocean. 



It is known from atmospheric ther- 

 modynamics that the heating of the 



atmosphere over a tropical ocean 

 takes place mainly through the heat 

 of condensation within precipitating 

 cloud. Hence, the rainfall record is 



also a record of the major year-to- 

 year variations of the atmospheric 

 heat supply from the ocean. Those 

 variations showed rhythms of about 



Figure IV-4 — CANTON ISLAND DATA 

 CANTON ISLAND 2°48'S I7I°43'W 



F 



86 



8 4' 



82' 



mm 

 200 



100 







F 



86' 



84° 

 82 



mm 

 400 



300 



200 



100 







F 



86" 



82' 



mm 

 500 



MOO 

 300 

 200 

 100 



1959 



"h-i-JL 



hi 



M 



1596 6 



I960 



1961 



m-i n 



759 2 



J hTI rh-rTHT-rrl 



rfh. 



30" 



28 9° 

 278° 



200° 



100° 



o 

 C 



30° 

 289° 



mm 

 400 



100 





28 9° 



278° 



mm 

 500 



400 

 300 

 200 

 100 



The figure shows a time-series of monthly air and sea temperatures and monthly 

 precipitation amount as measured at Canton Island from 1950 through 1967. 



85 



