16 



FOFONOFF 



[chap. 1 



(24) and (25) and should be used with reservations in any apphcations. Absolute 

 accuracy of F is difficult to establish in view of our inadequate knowledge of the 

 coefficient of thermal expansion (see Table I). Values of F differing by 50% can 

 be obtained from the two equations of state, (24) and (27). 



db 

 10000 



Fig. 4. The adiabatic lapse rate of temperature, F, as a function of temperature (°C), 

 salinity (%o), and pressure (db). The units of 7"" are °C/1000 db. 



The temperature lapse rate, F, enters into studies of temperature inversions 

 in the deep trenches in the ocean. It enters also into the formula used to compute 

 sound speed, V, (Kuwahara, 1938) given by 



V = [-v^'l{dvidp + Fdvld&)]''-^ (36) 



and into the calculation of static stability. E, from the equation (Hesselberg and 

 Sverdrup, 1914) 



" dp (d& _\ dp ds' 



E = -gjp 



d&\ 



ds dz 



(37) 



where g is gravity, p density and ;:; the vertical co-ordinate. ^ 



1 Ivanov-Frantzkevich (1953) has pointed out that the tables for the density derivatives, 

 dp/8& and dpjds, included in the paper by Hesselberg and Sverdrup contain systematic 

 errors amounting to a maximum of 10% of the values of the derivatives. These errors do 

 not seriously affect stability values for depths under 5000 m. 



