SECT. 2] I.AROK-SCALK INTERACTIONS 133 



drive sea ciirreiit and jet stream, adjusting their own imports, and thereby 

 back-reacting upon the energy-producing circulations of low latitudes. 



An important implication of Fig. 13 is found in comparing the deduced 

 magnitudes of the several heat-balance com])onents. These results suggest that, 

 in the general heat-energy exchange between latitudes, all four terms in (25) 

 play an important role and that neglection of any one would be a serious 

 omission. In particular. Fig. 13 suggests that the heat-flux divergence of sea 

 currents is comparable to that of air currents. If true, this means that "general 

 circulation" studies must eventually include both air and sea transports to- 

 gether, and that quite probably the latter cannot be ignored if long range 

 weather forecasts are to succeed. 



The transport figures presented earlier in Table I were obtained by separate 

 integration of the divergences in Fig. 13. The boundary conditions for total 

 heat-energy transport were obtained using the radiation balances, Rs, of both 

 hemispheres. The moisture transport across the equator (due primarily to the 

 Asiatic monsoon) was obtained from Budyko's statement (reference to Zubenok, 

 1956) that in the Southern Hemisphere the amount of precipitation is 12 cm/ 

 year less than evaporation. The boundary condition on sea transport was 

 obtained as described previously and that on the atmosphere's combined 

 sensible heat j)lus potential energy transport was found as residual and checked 

 in integration against total air and sea transport. 



A test of Table I may be applied by comparing its results with what we know 

 both qualitatively and quantitatively about atmospheric circulations and their 

 transports. In the first place we see that the boundary between Northern and 

 Southern Hemisphere air circulations falls naturally between 0° and 10°N, in 

 good agreement with the mean annual position of the equatorial trough (see 

 Figs. 22a, 23a). Latent heat is shipped into this zone from both sides and 

 sensible heat plus potential energy is exported poleward therefrom, as confirmed 

 by meteorological studies. Although the Asiatic monsoon and its seasonal 

 migrations somewhat mask this function of the trade-wind region on the 

 Northern Hemisphere side, it is revealed beautifully and to the expected 

 magnitudes (Section 5) on the southern side, where land effects are relatively 

 minor. 



Secondly, a fragmentary comparison of the deduced atmospheric transports 

 with more direct meteorological determinations (using mean observed air 

 motions and properties computed from meteorological data) is made in Table 

 IX. The figures of Mintz (1955) represent the sum of sensible heat transport by 

 geostrophic eddies and Cpd transport by the mean meridional circulation in 

 the year 1949. The figure in the last column at latitude 15° (Palmen, Riehl and 

 Vuorela, 1958) is 85% composed of total heat-energy transport {Cpd plus 

 latent heat) by the mean meridional cell, with the remaining 15% estimated 

 eddy-moisture flux. Since the year-round average would be about one-half 

 their winter figure, or 0.6 x lO^^ cal/sec, the agreement of these totally in- 

 dependent evaluations could hardly be better. The calculation for latitude 10° 

 (after Riehl and Malkus, 1958) is discussed further in Section 5B. 



