72 



calculations, we must know the data and their fluctuation scales to aiake 

 a meaningful interpretation of results. 



Figure 3 shows the evaporation integrated by latitude and broken down 

 by seasons. Water vapor constitutes more than three-fourths of the 

 atmosphere's energy source; this is provided by evaporating an average of 

 Just over 1 meter of sea water per year; about 75 percent enters the air 

 equatorward of 30° latitude. Figure k shors the oceanic heat budget calculated 

 by Budyko (1956), with roughly the same distribution of evaporative heat loss 

 (Oe = LE, where L is the latent heat of vaporization) as shown in Figure 3 

 from Jacobs. Note the very much smaller magnitude of Qg, the sensible beat 

 supply from sea to air; the ratio of Qs ^° Qe^ however, rises outside the 

 tropics, for reasons that are discussed later. 



Budyko' 8 Qg shows a similar equatorward dip as Jacob's does, a deduction 

 very crucial to the oceanographer as well as to the meteorologist. Q^q is 

 the oceanic heat flux divergence. In most studies, including Budyko 's, this 

 is deduced as a residual in the oceanic heat budget; it is essentially the 

 difference between the radiation balance R and the heat loss by evaporation, 

 Qe . This heat energy difference is what the equatorial ocean has left to 

 export to high-latitudes, to moderate their winter climates through warm 

 currents such as Gulf Stream and Kuroshio. By integrating O latitudinally, 

 authors like Bryan (1962) use the only way extant to arrive at oceanic heat 

 transports; these suggest that the oceans may carry as much as 15 - 20 percent 

 of the heat energy transported by the general circulation of the atmosphere. 

 Either this important result, or global radiation figures, must suffer an 

 agonizing reappraisal if Qg in equatorial regions undergoes significant 

 alteration, as Garstang's contribution to these Proceedings suggests it must. 



How does the air utilize these energy inputs from the oceans? To 

 begin to answer this question, let us examine Figure 5, the heat budget of 

 the atmosphere. First note the latitudinal uniformity of the radiation 

 sink Rg^, which corresponds to a cooling of about 0.75*^0 per day. From 60°N 

 to 60<^S, neither the sensible heating from the surface Qg, nor heat flux 

 convergence in the air (-Qva) does much to make up this large radiational 

 deficit - in fact the large negative peak in -Qya (^^^ heat flux convergence) 

 near the equator only compounds the air's heat losses in the tropics- As 

 we see from the top curve in the diagram, LP (precipitation heating), is 

 the vital atmospheric heat sourGe which makes up both the radiational loss 

 and provides for the heat export from the equatorial zone—' 



Clearly the air must have converted the latent heat gained from 

 evaporation into the usable or sensible form by making rain. Comparison 

 of Figures k and 5 show clearly that the main input and the main utilization 

 of the water vapor occur in quite different regions - our attention is 

 directed to the wind circulations and cloud formation process to explain 

 this difference. 



1/ In latitudes poleward of 60°, heat flux convergence becomes as 

 large or larger than precipitation warming. 



