142 MALKUS [chap. 4 



of year the expenditure of heat for evaporation and turbulent heat emission 

 markedly exceeds the radiation balance, that is to say, R — {Qe + Qs)=Qvo + 

 S<^0. Therefore a considerable amount of heat must come out from storage 

 in the deeper ocean layers. Comparison of areas in Fig. 18, however, shows that, 

 over a year, the sea receives more net heating by radiation than it expends to 

 the atmosphere, so that the oceanic flux divergence Qvo still averages out 

 slightly positive (cf. Fig. 11). 



In contrast to the conditions just illustrated for the western periphery of the 

 oceanic anticyclones, their eastern periphery is affected by cold sea currents 

 and the annual march of energy transactions changes accordingly. As an 

 example of the annual march of the heat-balance components in tropical areas 

 at the eastern periphery of oceanic anticyclones, we will consider the region 

 affected by the Benguela Current in the southeast portion of the Atlantic 

 Ocean (Fig. 19). In this case the expenditure of heat for evaporation, Qe, is 

 drastically reduced relative to that of the preceding region (Fig. 18), which is 

 located in the same latitudinal zone. Unlike almost every other region, the 

 turbulent flux of heat, Qs, very small in its absolute value, is negative or 

 directed from the atmosphere to the cold ocean surface. The absolute values of 

 Qs increase somewhat in summer, when the effect of the cold Benguela Current 

 is most pronounced. In this region, the ocean's gain of heat from radiation 

 balance and turbulent exchange is much larger than its losses from evaporation, 

 and a great amount of heat energy is transmitted to the deeper layers, which is 

 spent on heating the cold water- masses carried by the current. These expendi- 

 tures are especially large during the summer ; we can see from both Figs. 19 and 

 1 1 that Qvo has here its maximal (positive) annual average. 



In the subtropical belt, the main features of the annual march of the heat 

 energy transactions across the ocean surface are similar to those in the corre- 

 sponding areas of tropical latitudes. However, annual variations of radiation 

 balance are much more sharply pronounced, which is the result of considerable 

 changes in the average altitude of the sun during the year. Typical annual 

 variations of heat-balance components of the ocean surface in moderate 

 latitudes are presented in Figs. 20 and 21. Fig. 20 shows the situation in the 

 North Atlantic area affected by the Gulf Stream. At 55° latitude, the radiation 

 balance of the ocean surface has a large amplitude, with pronounced negative 

 values prevailing during winter. Here Qs and Qe are comparable. Qs is always 

 directed from the warm ocean surface into the atmosphere, is largest for any 

 oceanic region (comparable to that over deserts, where it has its global maxi- 

 mum) and is much larger in winter than in summer. The expenditure of heat 

 for evaporation, Qe, is also very large and shows a winter maximum. The ocean 

 surface must receive a great amount of heat from deeper layers to compensate 

 for the total expenditure from evaporation, turbulent heat flux and outgoing 

 radiation. Fig. 20 shows a very large negative sum ofQvo + S in winter. Compari- 

 son of areas shows that release of locally stored heat is not adequate to provide 

 the exchange, and in contrast to the locations of Figs. 18 and 19, Qvo averages 

 out large and negative, that is to say the powerful heat transports of the Gulf 



