Pressure 



(1) Maximum, minimum, and average pressure observed aboard 

 throughout the whahng season were 1,011-7 mb., 951-4 mb., and 985 mb. 

 respectively. 



Maximum change of pressure in three hours was 6-9 mb. when going 

 up and 7-7 mb. when down. Generally speaking the amount of pressure 

 change in three hours was least in December and increased toward March. 

 However, geographically, it was smaller in the Ross Sea than in the sea 

 area north of Balleny Islands. 



Temperature 

 ^2) Maximum and minimum of temperature observed on board the 



6-2° c. respectively, 

 c. to 2-0° c. Mean 



ship throughout the period were 2-7° c. and - 



Mean of the daily amplitude of temperature was 1-5 



temperature in the same period was lower by 1-5° c. in the Ross Sea 



than in the. sea area east of the Balleny Islands. 



Average humidity was different according to locations, generally 

 ranging between 85-90 per cent. But the humidit}- in the Ross Sea 

 was around 75 per cent., showing comparatively lower values than in 

 the other sea areas. 



Maximum and minimum sea surface temperatures, throughout the 

 period were 1-1° c. and — l-6°c. respectively. 



Winds 



(3) Westerlies prevailed in the northern territory of the whaling 

 ground, ranging from S. 63°-S. 65°. No conspicuous "difference between 

 the frequencies of easterlies and westerlies in the sea area east of Balleny 

 Islands was observed, and easterlies prevailed in the Ross Sea. 



The biggest frequency of wind force over the period was four. 

 The smallest frequency of strong winds was experienced in December 

 and increased toward March. Four observations of strong winds 

 exceeding 20 m/sec. were taken in the whaling ground. The occurrence 

 date of each and its accompanying weather conditions were as follows : — 



Month. 



Date. 



Longitude.! Press, 



Direc- 

 tion. 



Speed. 



Sky 

 Condition. 



Tendency 



of 

 Pressure. 



Jan. 

 Feb. 

 Feb. 

 Mar. 



Ascending. 

 Minimum. 



Generally, pressure goes down in the winds from N.E. quarter, and 

 goes up in the winds from S.W. quarter. Average of pressure changes in 

 three hours, classified according to eight points of wind directions, is as 

 follows : — 



67 



