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POLAR PROBLEMS 



(3) As regards the Antarctic stations the differences from Punta 

 Arenas are much greater in winter than in summer. These stations 

 thus exhibit a much more pronounced continental character than 

 Punta Arenas. 



(4) In summer the differences among the various Antarctic 

 stations are sHght, the mean temperature ranging between -2° to 

 1°. But in winter the differences are much greater. The condition of 

 the ice and the wind regime, different at each station, are the reasons 

 for these variations. From one year to another for the same reasons 

 the summer temperatures do not differ much, whereas the winter 

 temperatures may vary as much as 10° or more. 



As a first approximation the following mean summer and winter 

 temperatures may be assumed : 



DIURNAL VARIATION OF TEMPERATURE 



Theoretically the amplitude of the diurnal variation of the tem- 

 perature, zero at the south pole, should increase regularly to the 

 equator. This amplitude, which amounts to 8° at Buenos Aires, is only 

 2° at Staten Island and 1° to 2° at the Antarctic stations. 



The study of the diurnal variations of temperature during the 

 winter days in the Antarctic, when the sun is constantly below the 

 horizon, is of special interest. Even if only clear days be taken into 

 account in order to eliminate as much as possible the causes of corollary 

 variations, a rise in temperature is observed during the hours which 

 correspond to night. It is hard to offer a satisfactory explanation of 

 this rise, whose amplitude may be as much as 2°. 



The diurnal variation of the temperature obtained by taking the 

 means of 24 observations a day gives only a rather inaccurate picture 

 of the variation of the temperature during the course of the day. One 

 would have a very incorrect idea of the climate of the Antarctic if one 

 supposed that the temperature in winter does not vary more than 1° 



