

In the monsoon area, the character 

 of the weather, on the scale of indi- 

 vidual clouds, seems to be determined 

 by changes occurring successively on 

 the macro- and synoptic scales. Rains 

 set in — not when cumulonimbus 

 gradually merge but when a synoptic 

 disturbance develops, perhaps in re- 

 sponse to change in a major vertical 

 circulation. Showers, too, are part of 

 the synoptic cycle. Individually in- 

 tense, but collectively less wet, they 

 succeed or precede rains as general 

 upward motion diminishes. 



When synoptic-scale lifting is com- 

 bined with very efficient upper-tropo- 

 spheric heat disposal, the lapse rate 

 may be steep enough to support in- 

 tense convection. Then, a vast, "con- 

 tinuous" thunderstorm gives pro- 

 longed torrential rain. Many times 

 this takes place within the common 

 upward branch of two major vertical 

 circulations. 



Needed Scientific Activity 



Many tropical meteorologists have 



striven to make their work appear as 

 quantitative and objective as possible. 

 This commendable aim has led to im- 

 portant climatological insights. How- 

 ever, in synoptic studies their quanti- 

 tative results have usually been belied 

 by nature's quantities. A numerical 

 model which determines that air is 

 massively rising over the deserts of 

 Arabia has limited validity no matter 

 how quantitative and objective it 

 might be. Energy-budget computa- 

 tions in which precipitation and 

 evaporation are residuals, or must be 

 estimated, have also had their day. 



Forecasting and research should be 

 inseparable. The very few monsoon- 

 area weather services that enable 

 their forecast meteorologists to spend 

 at least one-third of their time on 

 research have thereby greatly en- 

 hanced staff morale and their scien- 

 tific reputations, to say nothing of im- 

 proved forecast accuracy. Combined 

 forecast-research programs could well 

 be successfully directed to solving 

 problems and to increasing the num- 

 ber of recognizable models of synop- 

 tic circulations. 



The area covered by synoptic analy- 

 ses should be sufficiently broad for 

 the major vertical circulations to be 

 monitored. Then interaction with 

 synoptic disturbances and consequent 

 effects on rainfall could be detected 

 and possibly anticipated. 



Mesoscale gradients within synop- 

 tic systems and their diurnal varia- 

 tions might be better understood 

 were studies to combine information 

 from weather radars and weather 

 satellites. Ceraunograms could help 

 bridge the gap between meso- and 

 synoptic scales. Aerial probing of con- 

 tinuous thunderstorms would likely 

 illuminate the shadowy picture we 

 now have of energy transformations. 



We should view the future of mon- 

 soon meteorology with optimistic dis- 

 content. Regional progress in under- 

 standing and forecasting weather has 

 been disappointingly slow. However, 

 attacks are being vigorously pressed 

 on problems of concern to the entire 

 monsoon area. What is needed is the 

 hitra-nrca exchange of people and 

 ideas. 



Tropical Meteorology, with Special Reference to Equatorial Dry Zones 



The outlook for meteorological ob- 

 servations in the tropics, as now 

 programmed, is excellent for many 

 purposes and far superior to the past. 

 Much can be done with existing and 

 prospective observations in the way 

 of field experimentation and synoptic- 

 statistical modeling. Ambitious proj- 

 ects like special or worldwide net- 

 works or expeditions, however, should 

 be undertaken only if the necessary 

 data base is really assured. Further- 

 more, meteorology, as a discipline, is 

 still far too self-contained; special 

 efforts are needed to promote inter- 

 disciplinary research. 



Four problems are particularly in 

 need of concentrated research in tropi- 

 cal meteorology during the 1970's: 



Water Supply — This age-old prob- 

 lem is becoming aggravated by popu- 

 lation increases in tropical countries, 

 as elsewhere. The need is to find 

 ways to assure an adequate water 

 supply over the middle and long 

 term — i.e., on a seasonal or annual 

 basis. Several avenues of scientific 

 development could be promising: 

 First, it has become more than ever 

 urgent to improve weather-prediction 

 methods. Second, experiments for in- 

 creasing precipitation artificially need 

 to be broadened to see whether 

 (a) such increases are possible at all 

 on tropical land areas; and (b) enough 

 water can be produced by man to 

 make a significant difference. While 

 not directly a part of meteorology, 

 desalination of sea water and diver- 



sion of large rivers (e.g., part of the 

 Amazonas in northeast Brazil) also 

 offer possibilities for enhancing tropi- 

 cal water supplies. 



Tropical Storms — Again, the prob- 

 lem has both predictive and modifica- 

 tion aspects. Prediction beyond 12 to 

 24 hours remains a large problem in 

 the areas affected by tropical storms 

 and hurricanes. The German Atlantic 

 Expedition of 1969 has again raised 

 the question of whether tropical 

 storms can be "modified" and, in- 

 deed, whether or not it would be wise 

 to do so. It should not be overlooked 

 that tropical storms in many situa- 

 tions and many areas bring great eco- 

 nomic benefits, even though news re- 



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