One point of interest mentioned by Dr. Spilhaus was that the trajectories 

 of the balloons do not agree very closely with the trajectories computed 

 from the geostrophic winds. The deviation was always towards regions 

 of lowest pressure. Dr. Spilhaus mentioned that oscillations observed 

 in the pressure-recording apparatus carried by the balloon had been 

 observed on a number of occasions, but it is not yet certain whether 

 they are oscillations of the atmosphere or of the balloon. 



GLOBAL TRANSPORT OF HEAT AND MOMENTUM 



By C. H. B. Priestley, C.ST.R., Melbourne, Australia 



[Abstracf] 



Global transport of mass, heat, water vapour, momentum, vorticity, 

 &c., are irregular processes whose irregularities are on the scale of cyclonic 

 and anticyclonic disturbances. A quantitative study of these transports 

 is required before we can approach a full understanding of the average 

 distribution of these elements, and, further, of the variation in distribution 

 with season and differences between one year and another. Probably 

 the first part of the problem to be faced relates to the mean distribution 

 with latitude. In this the meridional transport is the significant quantity. 

 Within any latitude zone there are processes occurring which left to 

 themselves, would effect a more or less continuous loss or gain of the 

 elements concerned — for example, a high-latitude zone would cool in 

 virtue of an excess of outgoing over incoming radiation, a zone in the 

 westerlies would slow down through surface friction, and so on. Relative 

 to the magnitude of the non-conservative influences, the mean conditions 

 in any latitude zone change, if at all, very slowly. In a study of the 

 mean latitudinal distribution it ma}^ be adopted as a working principle 

 that the loss or gain of heat, momentum, &c., is compensated by transports 

 from adjacent zones. In the case of mass, where no non-conservative 

 process is involved, the mean transport across any latitude must be zero. 



The technique for evaluating these transports has been described 

 elsewhere (see references), together with a discussion of the results 

 obtained from upper-air data at Larkhill covering a period of two years. 

 Further evaluations have been made from a year's observations at 

 Norfolk Island (29° S. latitude) and some isolated two-monthly periods 

 at various stations in or near 10° latitude in the Western Pacific Region. 

 The wind data available did not go above 400 mb. with sufficient regularitj'' 

 to permit evaluations above that level ; so the results are indicative 

 rather than quantitatively exact. Certain tentative conclusions ma}' be 

 drawn : — 



(1) A reversal in the troposphere of the eddy-flux of heat, a typical 



feature at Larkhill, is evidenced also at Norfolk Island.. 



(2) The percentage of the total eddy-flux of heat which takes place in 



latent form increases from about 50 per cent, at Larkhill to 

 about 70 per cent, in latitude 10°. 



(3) Great care must be taken to obtain representative data in low 



latitudes, and more than one ascent per day may be necessary 

 for an accurate evaluation. 



126 



