I. FUNDAMENTALS 



1. PHYSICAL PROPERTIES OF SEA- WATER 



N. P. FOFONOFF 



Much of our knowledge and understanding of the ocean's behaviour is 

 obtained through the apphcation of the conservation laws of mass, momentum 

 and energy to processes we observe to occur in the ocean. In order to formulate 

 these laws, we have to know certain properties of the fluid medium, such as 

 density, specific heat, viscosity and other physical and chemical characteristics, 

 as functions of temperature, pressure and salt content. The present discussion 

 is confined primarily to properties entering into the conservation equations 

 so that these properties may be described within the framework of a thermo- 

 dynamical system. Such a framework enables us to understand more clearly 

 the relationships among the various properties and will aid in the comprehen- 

 sive development of our knowledge of them. 



The incentive for much of the early studies of sea-water stemmed from the 

 need to be able to apply the conservation laws with precision in terms of 

 observations taken in the field. This was particularly true in the case of the 

 momentum equations with the development of methods of computing velocities 

 from the density distribution in the ocean. As a result, physical properties 

 entering into these equations have received more attention than others. There 

 are exceptions, of course. A number of properties have been studied because of 

 their importance to life in the sea. Others have been studied for technological 

 reasons and for the development of special techniques for the analysis of sea- 

 water. A complete discussion of all of these properties is beyond the scope of 

 the present undertaking. 



Our knowledge of sea-water properties has not developed systematically. Early 

 in the present century, a co-ordinated effort was made to determine the equation 

 of state and related physical and chemical properties. Since then the efforts have 

 been sporadic. Nevertheless important gaps in our knowledge are being filled and 

 efforts are being made to encourage and co-ordinate work in this basic field. ^ 



There are a number of descriptions, reviews and tables of sea-water properties 

 available in the literature. Among these are Kriimmel (1907), Matthews (1923), 

 Thompson (1932), Bein et al. (1935), Subov and Chigrin (1940), and Sverdrup 

 et al. (1942). More recent compilations and descriptions are those of Rouch 

 (1946), Lafond (1951), Dietrich and Joseph (1952), Dietrich (1957), Richards 

 (1957) and Montgomery (1957). 



1 See, for example, the report on the conference held at Easton, Maryland, September, 

 1958 — titled "Physical and Chemical Properties of Sea Water." National Academy of 

 Sciences-National Research Council, Publ. 600. 



[MS received March, 1960] 3 



