INTERNATIONAL ASPECTS OF OCEANOGRAPHY 



ment in oceanographic instniments. It is now 

 generally recognized that oceanographic stations 

 should be closely spaced in nets, so as to make it 

 possible to construct sections in almost any direc- 

 tion, and the observations and collections should 

 extend to the bottom. The instruments used in 

 recording temperatures and determining the depths 

 at which observations and collections are made must 

 be of a high order of precision. The bottles for 

 collecting water samples must be efficient — they must 

 not leak. The titrations for chlorine must be made 

 with the greatest attainable accuracy, for on them 

 depends the calculations of sahnity and density. 

 The object is to make accurate physical measure- 

 ments for use by mathematical methods, or by 

 graphical methods which require as great precision 

 as the mathematical treatment. 



Nearly all modern oceanographic work, both at 

 sea and in the laboratory, whether on shipboard or 

 on land, meets the requirements of accuracy, but 

 many older observations and determinations, some 

 of rather recent date, are faulty. Since Professor 

 Wiist in the article by him translated for this volume 

 has adequately discussed methods of testing the 

 accuracy of observations and determinations, noth- 

 ing more will be said on the subject in this place. 



For this volume the compilation for the Nor- 

 wegian, North Polar, and adjacent seas was made 

 by Dr. H. U. Sverdrup and Prof. B. Helland-Hansen ; 

 that for the Atlantic Ocean by Professor Wiist ; and 

 most of that for the Gulf of Mexico and Caribbean 

 Sea by Dr. A. E. Parr and Mr. C. Iselin. For 

 other ocean areas, except to use data already pub- 

 hshed by Professor Defant, the data have been 

 assembled by the compiler of this volume. As 

 has been stated, most modern records, such as 

 those on the Arihauer Hansen, the Dana, the 

 Discovery Expeditions, the Mabahiss, and a 

 number of other vessels are acceptable. For the 

 Pacific Ocean a card catalogue of stations at which 

 hydrographic observations were made, similar to 

 the catalogue initiated by Merz, was started. Many 

 hundreds of cards were prepared and T-S curves 

 of the usual kind were drawn for each of the stations 

 represented by a card. Two facts quickly became 

 obvious. The first was that most of the older 

 records were too inaccurate to be serviceable in the 

 study of the dynamics of the water masses, and, 

 except those stations plotted on Defant's charts, 

 most of them were discarded. The .second fact 

 was that to prepare cards for all stations in the 

 Pacific and to draw T-S curves would require 



more time than was available for the preparation 

 of this report. The cards and T-S curves that 

 had been prepared were used as checks, in so far as 

 possible. Those who may use this report will 

 have to be guided by the names of the vessels and 

 the dates of the observations in passing on the 

 trustworthiness of the records. 



There are a few warnings that can not be too 

 strongly emphasized. The finst is that sufficiently 

 accurate subsurface temperatures cannot be deter- 

 mined by the old style reversing thermometers that 

 were not equipped with auxiliary thermometers. 

 The auxiliary thermometers are essential. With 

 proper thermometric equipment the limit of error 

 of the temperature records should not exceed 

 ±.01°C., and it is possible to attain even greater 

 precision, limit of error about ±.003°C. The 

 safinities should be determined by or checked by 

 chlorine titration and the hmit of error should not 

 exceed ±.01 °/oo. The most recent memoir on 

 the determination of the constants of sea water is 

 that by Willy Bein, Heinz-Giinther Hirsekorn, and 

 Lotte Moller, entitled "Konstantenbestimmungen 

 des Meerwassers imd Ergebnisse iiber Wasserkor- 

 per."' Four methods for determining the density 

 of sea water are given: (1) Optical methods, by the 

 measurement of refraction; (2) electrical conduc- 

 tivity; (3) chlorine titration; (4) direct determina- 

 tion of den.sity. This publication should be studied 

 by all who are working on the physics of seawater 

 and dynamical oceanography. 



In addition to the warnings already given, there 

 is another. It is the necessity of precision in the 

 determination of the depths at which temperature 

 records and collections of samples are made. Depths 

 intermediate between the surface and the bottom 

 should be determined by means of improtected 

 reversing thermometers. Because of errors in the 

 determination of depths, probably due to too great 

 ware-angle, some temperature records that seem 

 to be accurate enough have had to be discarded. 



When the expense of conducting oceanographic 

 operation at sea is so great, no pains should be 

 spared to procure and use properly the best obtain- 

 able instruments. Unless the precautions above 

 indicated are heeded, observations made at great cost 

 may possess little, even no value. 



Surface temperatures and temperatures at shallow- 

 depths are considered not at all or only casually in 

 this compilation. Whenever a station is occupied 



« Institut fur Meere-skunde, Veroffent, N. F., Heft 28, 

 pp. Ill, 240, 14 pis., 1935. 



