SECT. 2] LARGE-SCALE INTERACTIONS 245 



Table XIX 

 Oceanic Heat Source for Moderate Hurricane 



8s denotes distance along each trajectory leg, from 90 to 70 km etc., computed from 

 dynamic model. 



8t is time needed to traverse leg, also computed from dynamic model. 

 86 is the increment in potential temperature in 8s and 8t. 

 8q is the increment in specific humidity in 8s and 8t. 



Here e is vapor pressure and ksp and kep are the Lagrangian coefficients of 

 turbulent exchange. Now Qsp St = Cp 86; Qep 8t = L 8q so that 



Cp8dl8s{To-Ta) = ksp (63) 



and 



L 8ql8s{eo-ea) = kep. (64) 



The ocean temperature is taken as 29.0°C as in the Daisy case (Fig. 68) so that 

 To — Ta = ^.0°C and eo — Ca follows from Table XVIII and psychrometric 

 tables. The resulting coefficients (last two columns in Table XIX) are constant 

 within computational limits, hence the air trajectory computed from purely 

 dynamic considerations is consistent with the independent constraints of 

 equations (61) and (62). The trajectory takes a course such that physically 

 impossible demands are not placed upon the thermodynamic interaction 

 between sea and air. This Lagrangian approach to exchange, viewing the 

 process by following air trajectories, may prove useful in other than hurricane 

 situations ; it is being developed by Riehl and his students in laboratory 

 treatments of extra-tropical cyclones. 



{v) Heat-energy budget of the inflow layer 



Up to now, calculations have followed a particle on its spiral path. Now heat 

 flux and energy exchange between air and sea will be examined spatially. The 

 motive is to compare the heat flux per cm^ of the ocean surface as determined 

 here and as estimated from the ordinary transfer formulas and with the normal 

 fluxes in the tropics. For this purpose, it will be necessary to construct a heat 

 budget, as in the trade-wind studies. 



