OCEANIC CIRCULATION AND OCEAN-ATMOSPHERE ITONS 



too, are limited both in time and 

 space. Major shipping lanes are fairly 

 well measured in many seasons. 

 Among the more systematically meas- 

 ured areas are the North Sea, the 

 California Current system, and the 

 Kuroshio Current. But data from the 

 areas that ships avoid, either because 

 of bad weather conditions or because 

 they do not represent profitable ship 

 routes, are generally sparse. Not only 

 is the arctic poorly represented even 

 with atmospheric information, but 

 also the South Pacific and large parts 

 of the South Atlantic. Very few areas 

 in the world are represented by a 

 data base sufficient to allow for sea- 

 sonal and nonseasonal variations. 

 Numerical models of the ocean are 

 also still in an early stage of develop- 

 ment. 



What is Needed 



A proper understanding of air-sea 

 interchange and of deep flow are 

 among the most urgent tasks of oce- 

 anic circulation research. We need to 

 determine which data are critical, ob- 

 tain them, and use them in mathe- 

 matical modeling of the ocean. Topics 

 of practical importance to man, re- 

 quiring urgent study, include fisheries 

 production in the world ocean; this is 

 related to ocean circulation, since the 

 latter controls the availability of plant 

 nutrients. 



Better understanding of the Arctic 

 Ocean is crucial to proper evaluation 

 of its possibilities as a commercial 

 route for surface vessels or subma- 



rines. Better knowledge of the deep 

 circulation and the rates of exchange 

 of ocean water — both from the sur- 

 face to the bottom and from the 

 deeper parts of one ocean to the 

 deeper parts of another — is particu- 

 larly important in the light of new 

 concerns over contamination and pol- 

 lution. While the ocean can act as a 

 reservoir to absorb, contain, and re- 

 duce much of the effluent now being 

 produced, it is not of infinite capacity 

 nor can it contain materials indefi- 

 nitely without bringing them back 

 onto the surface. 



Time-Scale — It is not possible to 

 lay out a time-scale for many of the 

 things that must be investigated. For 

 the problem of describing the mean 

 ocean, another ten or fifteen years 

 might be sufficient. In that period of 

 time, it would be feasible to collect 

 the additional data needed without 

 substantially expanding the facilities. 

 In order to accomplish this, however, 

 the various institutions capable of 

 carrying out the requisite measure- 

 ments would have to devote a greater 

 part of their time to this subject — 

 and this may not be desirable. 



Developing a data base to study 

 the time-variable ocean is a different 

 sort of problem. Since our under- 

 standing of the nature of time-varia- 

 tions is still in a primitive stage, we 

 must first learn how to observe the 

 phenomena and then begin a system- 

 atic series of observations in the ap- 

 propriate places. Progress has been 

 made in learning how to do this from 

 buoy deployments in the Pacific and 



Atlantic oceans. These are prelimi- 

 nary, however, and must be greatly 

 augmented before we can really un- 

 derstand even the scale, much less 

 the nature, of the anomalies being 

 observed. Understanding of this kind 

 usually advances step by step from 

 one plateau to another, but the steps 

 are highly irregular both as to height 

 and duration, and a feasible time- 

 scale cannot be estimated. 



Necessary Activity — On the one 

 hand, the scale of the problems dis- 

 cussed here suggests large-scale, 

 large-area, heavily instrumented re- 

 search carried out by teams of in- 

 vestigators. On the other, the history 

 of ocean circulation research has 

 shown that some of the greatest con- 

 tributions were made by individuals 

 — e.g., Ekman transport, Stommel's 

 westward intensification, Sverdrup 

 transport. A balance is required be- 

 tween large-scale programs compa- 

 rable to the space program and indi- 

 vidual small-scale projects. 



One of the first needs is to train 

 people able to work on problems of 

 both the ocean and the atmosphere. 

 The two fields have been far too sepa- 

 rated in most cases. People trained 

 in mathematics and physics are avail- 

 able, but the average student finds it 

 difficult to acquire a working back- 

 ground in both the oceanic and at- 

 mospheric environment; indeed, many 

 people trained in physics and mathe- 

 matics have limited backgrounds in 

 either environment, relying on theory 

 without adequate knowledge of the 

 structure of the two systems. 



On Predicting Ocean Circulation 



Nonspecialists tend to think of 

 ocean circulation systems as being 

 primarily a matter of geographical 

 exploration. We are not going to dis- 

 cover many new undercurrents, how- 



ever. Nor will simple-minded "moni- 

 toring" of ocean currents teach us 

 much. Twenty years of looking for 

 — and not finding — relations be- 

 tween changes in patterns of applied 



wind stress and the total transports 

 of currents like the Gulf Stream 

 where it passes through the Florida 

 Straits warn us that the chain of 

 cause and effect in the ocean is rather 



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