TEMPERATURE AND SALINITY 



for vertical sections of temperature and salinity, it 

 is customary to make a record of the surface tem- 

 peratures and to collect a sample of the water at the 

 surface for the determination of the salinity. 

 Schott has published compilations for both the 

 Atlantic and Pacific Oceans, and there are numerous 

 other publications. The Australian Meteorological 

 Service is preparing and distributing quarterly charts 

 of surface temperatures for the area bounded by 

 longitude 90° and 165°E. and by latitude 0° to 45°S. ; 

 the Royal Netherlands Meteorological Service has 

 recently issued a large two volume folio atlas of 

 charts for the China Sea; the Marine Observatory 

 at Kobe is publishing records of sea-surface tempera- 

 tures made by Japanese vessels; the Kydrographic 

 Office of the United States Navy has pul)lishcd 

 monthly charts of sea-surface temperature by one- 

 degree quadrangles for the north Pacific and it ha.s 

 other compilations in progress. Other organiza- 

 tions, such as the Marine Division of the Royal 

 British Meteorological Service, are also studying 

 sea-surface temperatures. Sea-surface tempera- 

 tures, as well as surface currents, are significant for 

 the study of various meteorological problems. A 

 note has already been made on the possible value of 

 such information in attempts at long-range weather 

 forecasting. The value for navigational purposes 

 is obvious. 



It is clear from what has been said that the 

 emphasis in the present section of this volume is 

 mostly on the temperature and salinity of the 

 water at depths of 1000 meters and more. Not so 

 much attention is given to shallow depths, but the 

 subject should not be passed over without some 

 consideration. Defant in his paper already referred 

 to, "Systematische Erforschung des Weltmeeres," 

 proposed to divide ocean waters between the Polar 

 fronts into three layers (a) a surface layer of agita- 

 tion and nearly uniform temperature; (b) a lower 

 layer in which the temperature decreases rapidly, 

 the layer of the thcrmocline; and (c) a still lower 

 layer in which the temperature range is slight, only 

 a few degrees Centigrade. The upper two layers 

 (a and b) are designated the troposphere; while the 

 lower layer (c) is called the stratosphere. The 

 papers by Wiist already cited contain discussions 

 of the tropospheric and stratospheric circulations 

 in the three oceans. Defant in his memoir, "Die 

 Troposphare"' gives an elaborate account of the 



' Defant, A., Schichtung und Zirkulation des Atlan- 

 tischen Ozeans, dritte Lieferung, Die Troposphare: Wis- 

 sensch. Ergeb. Meteor Exped. 1925-1927, vol. 6, pt. 1, 

 pp. 289-411, text-figs. 26-76, pis. 36-54a, 1936. 



various features of the Atlantic troposphere and its 

 circulation. The sources of the data are also given. 

 Defant follows Wiist in considering the minimum 

 oxygen layer as the base of the troposphere. Fur- 

 ther consideration of the southwestern north Atlan- 

 tic is contained in the two papers by Giinter Dietrich 

 cited below.' The interpretations of the tropo- 

 spheric and part of the stratospheric circulation of 

 the oceans advocated by Wiist, Defant, and Dietrich 

 are not accepted by all oceanographers, as has been 

 expressed by Iselin.' 



Iselin calls attention to two views regarding the 

 depth of the lower boundary of the major ocean 

 currents. According to the older view the velocity 

 gradually decreases with depth but there is some 

 flow parallel to the surface movements down to at 

 least 2,000 meters. According to the newer \'iew 

 the layer of water with the minimum oxygen content 

 is nearly motionless and marks the lower limit of 

 surface currents. The axis of the minimum oxygen 

 layer varies from depths of 300 to 400 meters near 

 the equator to 800 meters in higher latitudes. The 

 results of calculations of the volume and the velocity 

 of ocean currents are conditioned by which of the 

 above theories the particular investigator favors. 

 Very divergent results are obtained according to the 

 interpretation adopted. The relative merits of the 

 proposed interpretations will not be discussed in the 

 present volume. Only the differences of opinion 

 will be pointed out and it will be said that additional 

 careful, critical investigation is needed. 



The data on serial sections of temperature and 

 salinity besides being of value in studies of problems 

 of oceanographic circulation are indispensable for 

 computing oceanic depths from the time interval 

 in deep-sea sounding by means of echo methods. 



Since the positions of the .stations that have been 

 occupied for serial sections of temperature and 

 salinity are shown on the charts of the different 

 oceans, it does not seem necessary to discuss in 

 detail in the text of this volume those areas on 

 which information is deficient. But it will be 

 remarked, that there are still enormous areas in the 

 Pacific Ocean on which there are no data that can be 



* Dietrich, Giinter, Die Lage der Meeresoberflache im 

 Druckfeld von Ozean und Atmosphare, mit besonderer 

 Beriicksichtigung des westlichen nord atlantischen Ozeans 

 und des Golfes von Mexiko: Inst. Meereskunde Berlin, 

 Veroffentl. N. F., Geogr.-naturwiss. Reihe, Heft 33, pp. 

 1-52, Jan. 1937. 



Dietrich, Giinter, Ueber Bewegung und Herkuft des 

 Golfstromwassers: Ibid., pp. .53-91. 



' Iselin, Columbus, How deep do ocean currents flow: 

 Abstract of paper presented before National Academy of 

 Sciences, April 26, 1937, Science, vol. 85, p. 439, May 7, 1937. 



