on surface observations and upon observations of pilot balloons. Since radiosonde data have become more plentiful inequatorial regions, less emplasis has been placed on airmass difference and upon fronts. As far as we can tell from these observations the atmosphere more closély approaches autubarotropy near the *, equator than in any other region. The so called’ air masses in the tropics so closely resemble one another that even if surfaces of discontinuity existed between them (which may be doubted) there ‘gould be no concentration of solenoids in the frontal sone, and consecueiitiy no marked ecceleratio;r of circulation that could be attributed to a redistribution of miss, We must, in fact, look for sone source of energy otner than the initial mass distribu—— tion -to account for the development of the circulation of typhoons. It cannot be emphasized too strongly that by 194,0 many tropical meteorologists were convinced that except in the immediate neignbornood of typhoons the atmospheric variables, | pressure, temperature and density, upon whose gradients in space and time we base our major analytic techniques in high latitudes, reveal only weax gradients between 15° north and 15° soutn of the, equator, and that, tnerefore, the frontal techniques of high latitudes are only doubtfully applicable to. : tropical analysis. . It cannot be doubted that Deospermann, and others who followed hi.i, found "fronts" on synoptic maps for the tropical western Pacific. aircraft observations made during and after 6 5001623

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