117 

 are clearly not advective in origin, but are associated with the dynamics 

 of the disturbance involved. While these differences between the undisturbed 

 regime and the disturbed mode are noted, Figures 3 an<i ^ show that, with 

 the exception of AT in the disturbed case, there is little variation within 

 each mode or regime . The greater dependence of Tg - Tg upon wind speed in 

 the disturbed mode is related to the facJt that much lower air temperatures 

 are observed at lower wind speeds under these conditions, as_opposed to the 

 undisturbed regime. This leads to the reverse effect in Aq which is higher 

 at low wind speeds for the undisturbed case. The scalar average wind speed 

 is similar within similar intensity categories, i.e., the weak trade regime 

 speed is similar to the weakly disturbed mode wind speed. _ While it follows 

 from the above that, given similar Aq and u , similar Qg should be 

 obtained, it is also illustrated in Table 2 that the stability changes . 

 Under the strong trade regime the stability, as indicated by Rb, is on the 

 average, close to neutral. Maximum instability is reached in the weakly 

 disturbed mode, returning to weakly unstable in the strongly disturbed mode. 

 When a drag coefficient with a dependence upon stability is used, then these 

 changes in stability are reflected in changes in Cj). The changes in CD 

 produce an increase in latent heat trsinsfer during disturbed conditions even 

 though the wind speeds and specific hvunidity differences are similar to those 

 of undisturbed conditions. 



Since there is a fairly systematic increase in AT there is a cor- 

 responding increase in sensible heat transfer during disturbed conditions. 

 Changes in the Bowen ratio show that this increase is greatest with respect 

 to latent heat transfer in cases categorized under the weakly disturbed mode . 

 This suggests that sensible heat transfer may play an important role in both 

 the formative stages of a disturbance and in the peripheral regions of an 

 organized disturbance. 



The maximum exchange of total energy, Q^ , takes place in the disturbed 

 mode. The largest exchanges take place when conditions are closest to neutral 

 stratification and, in consequence, closest to conditions which are assumed 

 in the development of the exchange equations. Almost all of the relatively 

 large amount of total energy transferred from the ocean to the atmosphere 

 during undisturbed conditions is in latent form. It has been clearly 

 established by other workers such as Riehl (l95^j P- 56) and confirmed in 

 this region by La Seur and Gars tang (196^4^), that the greater proportion 

 ( > 50 per cent) of tropical precipitation falls in organized synoptic 

 disturbances . The proporation over the oceans may, in fact, be far larger 

 than this figure. Hence, before a significant proporation of the latent 

 heat accumulated in the tropics can be made available to the atmosphere, it 

 must be advected into organized synoptic disturbances. Condensation and 

 precipitation processes will release part of this latent heat directly into 

 the disturbance. This available energy may then be used both to fuel the 

 disturbance itself, as well as increase the potential energy in the upper 

 levels of the tropical and equatorial atmosphere. Therefore, the synoptic 

 disturbances, not only represent a localized maximum of energy flux, but 

 are also regions of horizontal convergence and vertical transport of the 

 energy supplied to the atmosphere over large regions of the tropics . The 

 extent to which individual synoptic disturbances contribute to the energy 

 budget of the atmosphere is examined below. 



