1 26 The Three-dimensional Temperature Distribution and its Variation in Time 



Table 52. (A) Adiabatic cooling {in 0-01 °C) resulting from an 



ascent of a water particle of temperature d'm up to the sea surface 



(a = 28-0 ; S = 34-85%o) 



(B) Adiabatic temperature change (in 0-01 **€) for the upper 

 1000 m at different salinities 



»(°C) 



all temperature differences except those due to adiabatic effects. The temperature of 

 each depth would be fixed by purely adiabatic displacements of water from the surface 

 or from the bottom to the given depth and in that way the vertical distribution of 

 temperature would remain invariable. In this case a mass of water from the surface 

 would be subjected neither to a force upwards nor to a force downwards, but would 

 always be in equilibrium with its surroundings (indifferent equilibrium). In a vertical 

 direction the potential temperature within it would be constant. The vertical distribu- 

 tion of temperature in such a case for some initial values at the sea surface is shown in 

 Table 53. In neutral equilibrium there is thus a slight increase of temperature with 

 depth which does not reach a temperature of 1-5 °C in the 10 km depth. 



Table 53. Vertical temperature distribution of indifferent equilibrium 



If the vertical temperature gradient is greater than the adiabatic, i.e. if the potential 

 temperature calculated from the temperature in situ increases with increasing depth, 



