RECENT ACCOMPLISHMENTS IN BASIC OCEANOGRAPHIC RESEARCH 



The major scientific accomplishments in 

 oceanography over the last twenty years 

 not only reflect the achievements of the 

 earlier Committee on Oceanography but 

 also provide for speculation as to future 

 trends. A considerable impetus was given 

 to work on instrumentation and applied 

 oceanography as a result of the war, when 

 for the first time sufficient funds were avail- 

 able. Work on a greatly expanded scale 

 made it necessary to recruit scientists from 

 allied fields: physics, geology, geophysics, 

 meteorology, etc. A number of these, as 

 well as several officers with scientific back- 

 ground from both the Army and Navy, 

 were indoctrinated at one or another of 

 the oceanographic laboratories, and have 

 elected to remain in oceanography. These 

 and others trained in recent years form a 

 nucleus of 80 to 100 physical oceano- 

 graphers in this country, compared with 

 perhaps a half dozen prior to 1930. This 

 is a contribution to the progress of oceano- 

 graphy not to be overlooked. 



THE PHYSICS OF THE SEA 



On the whole, physical oceanography has 

 been advancing much more rapidly in re- 

 cent years than any of the other branches 

 of the svibject. Not until the physical char- 

 acteristics had been described in a realistic 

 and detailed manner was it possible to for- 

 mulate the problems in physical oceano- 

 graphy except in a vague way. In the last 

 twenty years a great quantity of data has 

 been amassed. The accumulation of sub- 

 surface temperature and salinity observa- 

 tions off both coasts of the United States 

 is now comparable to that collected prior 

 to World War II in the North Sea and off 

 Japan. As a result, it now becomes appar- 

 ent that the concepts of the oceans based 

 on the work of the earlier expeditions have 

 been greatly oversimplified. With the in- 

 formation we now have, a few limited 



areas of the oceans can be reliably de- 

 scribed. This knowledge, a major contri- 

 bution in itself, formed the basis for the 

 outstanding textbook on oceanography 

 written during this period. The Oceans, by 

 Sverdrup, Johnson, and Fleming. The com- 

 pilation of these data together with the 

 development in instrumentation was pre- 

 liminary to still more recent theoretical ad- 

 vances and to greatly improved tactics in 

 field work. 



The amassing of temperature data has 

 been much facilitated of recent years by 

 the development of the bathythermograph, 

 a practical diving thermometer for use from 

 a ship underway at normal speeds. For 

 depths down to about 300 meters it is now 

 possible to obtain the detailed temperature- 

 depth curve as frequently as may be ad- 

 visable. As a result a research vessel can 

 be maneuvered to follow any particular 

 thermal feature. This technique has been 

 particularly effective in tracing the boun- 

 daries of currents— which, contrary to ear- 

 lier ideas, have been found to follow a 

 tortuous course. The bathythermograph is 

 also greatly facilitating the accumulation 

 of data on the heat exchange between the 

 ocean and the atmosphere, both seasonally 

 and in its variations from year to year. 



The advantages of the bathythermograph 

 as a means of estimating the refraction 

 effects in acoustical transmission near the 

 surface were so great that funds were 

 quickly provided by the Navy for the de- 

 velopment of other instruments for similar 

 purposes. One of these, a salinity-tempera- 

 ture-depth recorder, provides a rapid means 

 for surveying shallow coastal waters, often 

 so complex and variable that a true under- 

 standing of them could not be obtained 

 with older methods. Already a significant 

 start has been made on estuarine flushing 

 problems using this and other continuous 

 recording instruments. 



