67 



Sea-air interaction affects every scale of motion and nearly every 

 process in the tropical atmosphere. It enters every problem in which we 

 attempt to maiie an explanation or a prediction - from inteirpreting the cloud 

 forms we see on satellite pictures to the oceanic semi-diurnal convection 

 cycle and the formation of hurricanes . 



But what do we mean by sea-air interaction? How do the sea and air 

 affect each other in the tropics? Since we are mainly discussing meteorology 

 here and not physical oceanography or biology, let us examine more specifically 

 how the physical interaction between the sea and the air affects the atmos- 

 phere . This takes place by means of exchanging of property: primarily 

 moisture, heat, momentum and salt. Concerning each of these exchanges we 

 must ask three main questions, namely: 



1. What is its magnitude and distribution in space and time? 



2. What is it controlled by, that is, what is its functional 

 dependence? 



3- What is its role in atmospheric processes and how important 

 in this role? 



Momentum flux is intimately coupled with the others, as is pointed out 

 in the article by Roll in these Proceedings . Salt flux is probably important 

 in atmospheric thermodynamics as well as in the condensation process; 

 important research is going forward with its highly necessary documentation 

 (cf. Woodcock, 1958). This article, however, will restrict its subject to 

 moisture and heat fluxes, because of their large role in the energetics of 

 air circulations . 



First, we will examine their global distribution and role in planetary 

 flows . This will lead naturally to a discussion of convection and cloud 

 patterning and the role of exchange in these processes . Finally, we shall 

 conclude with a more detailed consideration of the interaction between 

 oceanic fluxes and air circulations in the trade-wind and equatorial trough 

 zones of the tropics . 



Knowledge of the role of sea-air exchange in atmospheric circulations 

 has burgeoned since World War II - in some cases it has even been incorporated 

 into models, both theoretical and numerical. There is, however, one major 

 reservation which relates to the most serious bottleneck facing sea-air 

 interaction studies and facing tropical meteorology - that is, for all 

 practical purposes, we have no direct way to evaluate these fluxes . We can- 

 not chart them from direct measurements, as we can sea temperature, for 

 example . 



Nearly all our knowledge of heat and moisture fluxes from sea to air 

 is based on indirect calculations from the so-called transfer formulas or 

 Jacobs formulas. These are partly empirical and partly based on a simplified 



