PART VI — PRECIPITATION AND REGIONAL WEATHER PHENOMENA 



where predictions are most needed. 

 Continental models will necessarily 

 differ from oceanic ones. Continents 

 do not have surface-heat storage in 

 the sense of the oceans, and frictional 

 stresses as well as nuclei spectra for 

 condensation and freezing are differ- 

 ent. Oceanic research could thus use- 

 fully be supplemented by research 

 over land. Collaboration with exist- 

 ing continental experiments, such as 

 that of northeastern Brazil, could 

 bring large technical rewards. 



Interhemispheric Communication 



In many ways, it appears that the 

 center of the equatorial convergence 

 zone separates the hemispheres mete- 

 orologically as well as physically. 

 Each has a self-contained energy and 

 momentum budget, for example. If 

 this picture were true for all time- 

 scales, then the two hemispheres 



could be treated as independent of 

 each other for all practical meteoro- 

 logical purposes. 



No one really believes this, how- 

 ever, although there is much doubt 

 as to the time-scale on which inter- 

 hemispheric mechanisms are impor- 

 tant. Preliminary calculations based 

 on data dating from the International 

 Geophysical Year (IGY), in the 

 1050's, have not revealed any impor- 

 tant connections; but then, the tropi- 

 cal network of IGY was so deficient 

 that it is impossible to treat these 

 data as definitive. Here we see the 

 danger of inadequate observational 

 efforts. Better data are likely to 

 emerge from superpressure balloons, 

 World Weather Watch stations and 

 satellites, and the buoys and other in- 

 stallations of the GARP network. If 

 these networks and data sources are 

 kept up and expanded, a good start 

 could be made during the 1^70's on 



resolving the questions relevant to 

 the importance of interhemispheric 

 communication for long-range 

 weather changes. 



Irrespective of long-period weather 

 control, an understanding of mass ex- 

 changes across the equator is impor- 

 tant to the prospects for worldwide 

 pollution control. We know that mass 

 exchanges across the equator occur, 

 but we need to determine whether the 

 drift of pollutants across the equator 

 occurs with indifferent distribution in 

 troposphere and stratosphere. If that 

 is the case, nothing can be done to 

 protect one hemisphere from the 

 other, but there may be point-, or 

 small-area, injections in preferred and 

 stationary locations. If that is so, 

 trajectory calculations toward these 

 areas and measurements along them 

 would at least permit warning of im- 

 pending transports of particular pol- 

 lutants at a high level. 



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