As a consequence of our conception of the cyclone chimney being 

 from 2 to 4 km. high, we advised the pilots of the Chinese air lines as 

 early as 1936 to fly above any typhoon which would be on the track of 

 their flight. We had an Italian Navy plane, Savoia-Marchetti type, 

 passing over a typhoon near Foochow in 1935. The pilots reported blue 

 skies all above them (they flew at 4, then at 5 km. height) with a very 

 strong horizontal current aloft, flowing in the direction of the movement 

 of the typhoon. 



While admitting that elsewhere typhoons and tropical cyclones can 

 be higher, we would like to know what results have been obtained by the 

 pilots of the Australian air lines. In the Far East we have had more than 

 ten cases in which a plane, flying not far from a typhoon, found " stratified 

 air " and cloudy to blue skies above 8,000 or 10,000 ft. 



Discussion 



Messrs. Simpson and Hutchings both stressed the variations that could 

 take place from typhoon to typhoon and from place to place, and other 

 speakers brought forward more evidence to support Father Gherzi's 

 contention that sometimes typhoons were phenomena of very low levels. 

 It was agreed, however, that this was not the general rule. 



With regard to Father Gherzi's ideas of the steering of typhoons 

 by the thermal wind or wind at some upper level, the opinion seemed 

 to be that thermal steering was a useful concept, but that the level of 

 steering was likely to vary greatly according to the stage of development 

 of the typhoon. 



Mr. vSimpson presented some conclusions to show that the typhoons 

 would move along the tongues of warm air as shown by the isopleths 

 of mean virtual temperature between the 700 and 500 mb. levels. 



Mr. Priestley pointed out the danger of applying thermal steering 

 concepts depending on the geostrophic wind to typhoons in low latitudes. 



ON THE THEORY OF TYPHOON FORMATION 



Bv S. AoKi 



36 



