390 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



10° 



15 



20° 25' 



NORTH LATITUDE 



30° 10° 



15° 



20° 

 NORTH LATITUDE 



30° 



Figure 16. — Meridional profiles showing the relative magnitude of the components entering into the net 

 heat exchange across the sea surface at 160° W. Panel A — June, panel B— December. (Q, — heat absorbed by 

 the water, Qb — back radiation, Q, — heat used for evaporation, Qc — conduction of sensible heat, H — net 

 heat exchange across the sea surface.) 



layer, z, the specific heat, Cp, and the density of 

 sea water, p. 



This is illustrated in figure 17 by the meridional 

 profile of the net heat exchange and the equivalent 

 change of temperature at 160° W. in June and 

 December. For convenience the net heat ex- 

 change is presented in units of kilocalories per 

 square centimeter per month (kcal. cm.~^ mos.~'). 

 At 12° N., for example, the net heat exchange 

 varies from approximately +0.3 kcal. cm.~^ mos."' 



in December to +3.0 kcal. cm."° mos."' in June; 

 a tenfold increase. The effect on the change of 

 surface temperature, on the other hand, varies 

 from about 0.1 °C. mos."' to 0.3 °C. mos."', only 

 a threefold increase, reflecting the effect of the 

 seasonal change in the depth of mixed layer at 

 12° N. (fig. 2). 



At 30° N. the net heat exchange varies from 

 about +7.9 in June to —5.9 kcal. cm."^ mos.~' in 

 December. The equivalent change of surface 



