DISCUSSION AND ANALYSIS OF WINDS 



743 



SOUTH AFRICA. 



The winds of South Africa are very little known, except in the British Colonies 

 in the extreme south. 



It has been said already that along the west coast of S. Africa there were S. W. 

 winds, that is, from the cold marine current towards the land. On the E. coast of 

 Africa easterly winds prevail, although from December to February they are rather 

 N. E., as the southern hemisphere is much heated then, and the pressure is higher 

 on the north. 



The mean direction and amount in percentage are as follows : — 



Mozambique Channel, 15O-20° S. . 

 Indian Ocean, 20°-25o S., 4'7°-50o E. 

 Port Louis, Mauritius 



June to August. 

 S. no E. .85 

 S. 84° E. .71 

 S. 61° E. .66i 



December to February. 

 N. 31° E. .28 



N. 61° E. .66 

 N. 83° E. A1 





June to August. 



December to February. 1 



fei 



fe5 



H 



H 

 K 



m 





^ 







4 



17 



43 



29 



9 



1? 



11 

 6 

 5 

 3 

 7 

 3 



19 



16 



7 



8 



2 



0.3 



H 



27 

 36 



29 



10 



1 



0.5 



H 



03 



13 

 21 

 31 



27 



7 

 9 



5 

 2 

 10 

 13 

 56 

 67 



03 



6 



2 



6 



27 



19 

 9 



6 

 6 

 3 

 5 

 7 

 4 



13 

 11 

 9 

 6 

 4 

 7 



Zone 22. N. 36. Madagascar .... 



Port Louis, Mauritius . 

 " 24. N. 38. Natal, S. E. Africa 

 " 24. N. 44. Graliamstown, Cape Colony . 



Graff Reinet, Cape Colony . 

 " 25. N. 41. Cape Town, Cape Colony 



4 



3 



10 



1 



34 



31 





 2 

 7 

 4 

 2 

 6 



4 

 31 

 22 



2 

 2 

 6 



21 

 48 



19 

 4 

 8 



82 



52 



6 

 9 

 3 

 15 

 14 



IS 



1 



9 



24 



7 



1 



1 

 3 



9 



18 



4 



1 



In Natal the general character of the winds is tropical, they are still E., but 

 more regular in the summer season of the southern hemisphere (December to 

 February). 



In the Cape Colony the winds are regularly sub-tropical: polar (S.) from 

 December to February, and equatorial (N., N. W.) from June to August. The 

 regular yearly movement of the belt of highest pressure which forms the polar 

 limit of the trades is seen here, in the extreme S. of Africa. In the warm season 

 (December to February) it moves southward further towards the pole, so that 

 the Cape Colony has then S. winds. In the winter (June to August) it recedes 

 northward towards the equator. A reference to the map of isobars (Plate 14) will 

 show that in July (midwinter) the pressure is very high in S. Africa, the isobar of 

 30.2 inches going from the Atlantic to the Indian Ocean, in latitude about 30°. 

 In January, on the contrary, a pressure of 30 inches is found nowhere on the 

 continent of S. Africa, nor on the Indian Ocean, but is restricted to the region of 

 the cold marine current on the Atlantic. 



