(437) 



NOTE ON THE CONNECTION BETWEEN THE BAIN- 

 FALL AT DURBAN AND MAURITIUS. 



By T. F. Claxton, F.R.A.S., 



Director, Royal Alfred Observatory , Mauritius. 

 (Read October 31, 1906.) 



The present notice contains the first results of an inquiry into 

 the possibility of seasonal weather forecasts for Mauritius. 



Mauritius weather being controlled to a much greater extent 

 in winter than in summer by the number and intensity of the anti- 

 cyclones, with their attendant V-shaped depressions, which pass 

 to the south of Mauritius from the Cape towards Australia, it was 

 thought that an examination of the weather conditions to the 

 south-west of Mauritius in the winter months might give some 

 idea of the subsequent weather at Mauritius. Monthly departures 

 from average of the various meteorological elements at Durban 

 were compared with those at Mauritius ; the latter were also com- 

 pared with the monthly departures from average of the pressure 

 gradient between Durban and Mauritius * ; but there appeared to be 

 no connection between them. 



The next step was to examine the weather conditions at Durban 

 antecedent to winter droughts in Mauritius, and still there appeared 

 to be no connection ; but on reversing the argument, examining the 

 weather conditions at Mauritius following droughts at Durban, a 

 connection at once became apparent. 



In the following table are given particulars of the droughts which 

 have occurred at Durban since 1873 — the year in which observations 

 were commenced — and of the corresponding droughts in Mauritius. 



The information for Durban has been extracted from the annual 

 reports of the Government Astronomer, and is based upon rainfall 



* The abnormality curve of pressure gradient follows very closely the abnormality 

 curve of pressure at Durban, the departures from average being so much larger at 

 Durban than at Mauritius. 



