THE MEAN MONTHLY AIR TRANSPORT INTO THE CONTINENT 

 OF AUSTRALIA, AND ITS SEASONAL VARIATION 



By H. Arakawa, T. Sakita, S. Fujii, I. Fujinuma and T. Hosino, 

 • Central Meteorological Observatory, Japan 



The present paper treated the wind conditions around the continent 

 of x\ustraHa on the basis of the pilot charts of the Indian Ocean, regularly 

 issued by the Hydrographic Office of the U.S. Navy Department. The 

 charts contain a great amount of information useful to sailors as well 

 as weather men. This paper is a discussion of the wind conditions on 

 the boundary part of the Continent of AustraUa, of which the representa- 

 tion of the \\ind is a point of chief interest. As to the interpretation of 

 the v/ind roses, the following quotation from the text printed on the charts 

 may give the best account. 



The wind roses in each 5-degree square show the frequency-, the direction, 

 and the average force of the winds that may be expected to prevail within that 

 square. At the request of tliis office the wind percentages were concentrated 

 upon eight points . . . The length of the arrow measured from the centre 

 of the circles gives, by means of the attached scale, the number of times in each 

 100 obser\'atidns that the wind may be expected to blow from the given point. 

 The number of the feathers indicates the average force of the -wind according to 

 the Beaufort scale. The percentage of calms, light airs, and variable winds is 

 .shown bv the number within the circle 



Fig. I. 



There are several different scales known as " Beaufort " in use. 

 That adopted by the Hydrographic Office and Weather Bureau is known 

 as the " Scott " scale and differs slightly from the EngUsh. 



To get an immediate perception of the actual average air transport 

 we calculated the resulting mean velocity, representing the average air 



/SO 



105 



