SEASONAL WEATHER PREDICTION — WALKER 



137 



large regions, and the most southern station from which as many as 

 25 years of data are forthcoming is the South Orkneys. Its winter 

 pressure does show the opposition that we should expect with that 

 of Australia, but not with the high-pressure region of South America 

 or Mauritius; so that it gives little support to the view that there is 

 a general pressure oscillation between the low- and the high-pressure 

 belts of the Southern Hemisphere. On the other hand, the air tem- 

 perature at the South Orkneys may be regarded as an index of the 

 sea temperature; and as the ocean current through the Drake Pas- 

 sage would take about a year to reach South Africa, we are not 

 astonished at the relationship of 0.56 between the South Orkneys 

 air temperature in winter and that of the next winter at Cape Town. 



NORMAL 



NORM&L 



FiGUHB 14. — Departures from normal of Ano Nuevo temperature, June to August, and of 

 Cape Town temperature, June to August, of tbe following year. 



This is not, however, as close as the corresponding relationship of 

 0.84 shown in figure 14 between the winter temperature at New 

 Year Island at the extreme southeast of South America, and that 

 at Cape Town a year later. The far greater influence of New Year 

 Island is interesting, since between Cape Horn and the South Ork- 

 neys there runs ENE. a line which the recent Discovery expedition 

 calls the Antarctic Convergence ; here the cold antarctic water meets 

 the northern warmer water and dives under it. So while the current 

 flowing past New Year Island can after a year approach South 

 Africa, that from the South Orkneys is cut off by a barrier. 



If I may summarize these remarks, I would say that although 

 seasonal foreshadowing is still very imperfect it has come to stay ; for 

 situations will arise from time to time, as they did in India in 1905, 

 in which it can be foreseen with practical certainty that rains will 



