SECT. 2] 



LAKGE -SCALE INTERACTIONS 



267 



to the connection is found in Fig. 76. Its remarkable feature, which recurred in 

 all the discrete periods reported in Table XXIII, is the convergence throughout 

 most of the cloud layer. This is different from the uninterrupted divergence 

 found in cases of cold air outbursts over continents (Palmen and Newton, 

 1951) and suggests that the cumulus convection caused by the oceanic heating 

 markedly affects the synoptic-scale convergence field. This point has been 

 pursued in a fascinating paper by Winston (1955), who finds the convectively- 

 imposed ascent a key feature of a deep cyclonic development in the Gulf of 

 Alaska. There a major wave trough began to develop in the westerlies due to 

 planetary-scale dynamic readjustments. This induced an outflow of continental 

 air over the warm coastal waters, which in turn brought about the violent 

 deepening of a major cyclone ; the latter could not be predicted by the standard 

 dynamic methods of vorticity advection. Since these explosive developments 

 have subsequent pronounced effects upon the planetary wave patterns down- 

 stream, an exciting and fruitful area of research has been opened, coupling 

 exchanges, via convection and imposed vertical motions, with large-scale 

 circulation dynamics. The research aircraft has opened another avenue for 



105 110 



115° 120° 125° 130° 135° 140° 145° 150° 



^ ttill \ V V ^. 



100 200 100 400 500 



•O to 200m obov« seo lavet 

 ^ 200 to 2000m obove teo lavtl 

 ^Over 2000m obove sao lavtl 



115° 120° 125° 130° 135* 140° 145° 



atmosphere over Japan Sea and Kuroshio region. (After Miller and Mantis, 1947, Figs. 1, 3.) 



(b) Map of cyclogenetic region off east coast of Asia showing February sea-surface 

 isotherms and the course of the warm Kuroshio, or Japanese current, in winter. 



