OCEANOGRAPHY IN THE UNITED STATES 281 



of the water vapor condenses into liquid water is used to drive the 

 vast and steady easterly trade-wind systems on both sides of the equa- 

 tor. Most of the remaining water vapor (which in energy content is 

 enough to maintain all the global winds several hundred times over) 

 is carried equator-ward by these trade winds to the so-called equa- 

 torial trough zone — tropical storm and hurricane factory — upon 

 which our marine meteorology studies have recently shed some rather 

 exciting light. 



Here the real fuel combustion of the atmosphere is done, as the 

 accumulated water vapor is raised in towering thunderhead and anvil- 

 topped cumulonimbus, condensing and thereby releasing "sensible 

 heat" — available to be exported poleward, much later to drive mid- 

 latitude cyclone and jet stream, and balance the spaceward radiation 

 losses of the long polar night. 



What is most remarkable, however, about the atmosphere's equa- 

 torial "firebox" is that this energy conversion and release takes place 

 in a very small number of "cylinders" — 10 percent of the equatorial 

 trough area is occupied at any one time by vortical storms (of wliich, 

 incidentally, maybe 1 in 50 becomes a hurricane), 10 percent of the 

 area of these is experiencing active rain, while only 10 percent of this, 

 or 0.1 percent of the total trough zone, is occupied by the giant cumu- 

 lonimbus whose intense updrafts convert the latent heat and propel 

 it to great heights. Just 1,500 to 5,000 runaway cloud towers around 

 the globe are enough to drive the engine, to combust the vast amount 

 of water vapor fuel accumulated from the oceans and shipped in by 

 the trade winds — and elevate the product to great heights where it is 

 available to be exported to distant regions : later a small fraction is 

 used to maintain high-level jets, form cyclones and drive the Gulf 

 Stream. If man dreams of ever controlling or regulating the large- 

 scale behavior of his atmospheric heat engine, he would do well to 

 look for those links in its operation where much is done in restricted 

 regions, such as the equatorial trough, by relatively few elements, such 

 as the giant clouds, and attempt to understand these rather 

 thoroughly. He must seek to isolate key processes and key problems 

 and pursue them with every possible form of attack — theoretical, with 

 equations and high-speed electronic computers; observational by in- 

 strumenting aircraft, helicopters and balloons to penetrate the active 

 heart of the phenomenon; experimental by designing simplified 

 models in the laboratory, and by all these approaches jointly and to- 

 gether, interchanging questions and knowledge. 



Convection is a key problem and has a direct practical impact on 

 man. A major fraction of the world's rainfall, all its hail, lightning, 

 and tornadoes are convectively produced and convection forms the 

 driving jxiwer of the destructive tropic-born nemesis, the hurricane. 

 That it is a key problem to progress in understanding and eventually 

 influencing the overall behavior of the atmosphere, we have seen by 

 the brief picture just painted. 



Ten years ago this picture could not have even been sketched. It 

 has been put together, in considerable part here at Woods Hole, due 

 in good measure to the long-sighted support of governmental agencies 

 such as the Office of Naval Research. Research is a long, slow process, 

 and sudden insights and turning points often occur when least ex- 

 pected. For example, some of our work on individual cumulus cloud 



