To examine qualitatively the wind effect on the stratified ocean, 

 as shown in figure 3a, let us assume that the velocity of the wind 

 induced gradient currents decreases with increasing depth. In the 

 steady state the sea surface slopes must have reached a certain 

 stationary inclination, and the mass distribution (temperature field) 

 must have changed in such a way that beneath the layer of frictional 

 influence from point to point the geostrophic equilibrium condition 



37 f tanY <5 dz ' 



is nearly fulfilled, or that, approximately, 



du _ £ 1 d£ 

 oz f p dy 



holds. Here, u is the zonal velocity of the gradient current in 

 the x-direction (indicated in figure 3b by feathered arrows), p the 

 density (which in our model is only a function of the temperature 

 at constant pressure), and y the inclination angle between the lines 

 of equal density and the (horizontal) level surfaces. Qualitatively, 

 the distribution of isotherms in the meridional cross-section under 

 these conditions should look like the dashed lines, as shown in 

 figure 3b. 



When looking in the direction of the current between 60°N and 

 30°N the isotherms must slope down from the left hand side to the 

 right hand side, that is, from north to south, provided the current 

 decreases with increasing depth, and they must slope down from the 

 equator towards 30°N, since the wind induced gradient current in 

 this region flows from east to west. This leads to a thick warm 

 water accumulation around 30°N, and to a relative cooling in corres- 

 ponding depths in equatorial regions. Furthermore, the vertical 



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