The highest part of the tropopause shows a marked oscillation in 

 position, according to the season of the year, but even in the winter 

 season it seems to lie in the Southern Hemisphere. This marked asym- 

 metry would seem to be a peculiarity of this region and is probably not 

 a general feature of the southern circulation. 



It is of interest also to note that in certain sub-tropical latitudes 

 temperatures in the upper part of the troposphere are warmer in winter 

 than in summer. 



Regarding the seasonal variation of the tropopause it would seem 

 that in this region the tropical tropopause is higher in summer than in 

 \yinter as is also the polar tropopause. Variations of the latter tropo- 

 pause from winter to summer, however, seem to be somewhat greater. 

 This variation of the tropical tropopause is contrary to the variation 

 given by Willett(2) for the North American region. 



However, the conclusions reached in this paper obviously need con- 

 firmation by the examination, of a larger number of records. This task 

 is now being undertaken, and the results will be presented as soon as 

 possible. 



References 



(1) Court, A. : Bulletin of American Meteorological Society, May, 1942. 



(2) WiLLETT, H. C. : Descriptive Meteorology, 1944. 



HEAVY RAINS IN HAWAII AS RELATED TO IMPORTATION 

 OF COLD AIR ALOFT 



By R. H. Simpson, U.S. Weather Bureau, Honolulu 

 [A bstract] 



Analyses of time cross-sections for Honolulu soundings are considered 

 in relation to flow patterns over the Eastern Pacific during periods of 

 heavy rain in Hawaii. It is shown that flow patterns become more 

 clearly related to rain occurrences when analyses are extended into the 

 middle and upper troposphere. This is supported by recent studies of 

 Mordy and Leopold which show conditions at 300 mbs. to be most 

 significantly correlated with the ' occurrence of general rain. Outbreaks 

 of rain are preceded by importations of cold air aloft which may reach 

 the Hawaiian area either from the north, upon arrival of a polar trough, 

 or from the east in connection with easterly waves. Heaviest rains 

 occur with the simultaneous arrival of cold air from both sources. 



When cold air aloft streams southward into the tropics and becomes 

 detached from its source, it tends to disappear rapidly through subsidence, 

 but may occasionally collect in a broad pool and persist. It is noted 

 that the latter condition frequently seems to foreshadow the development 

 and westward movement of an easterty wave. 



WEATHER OBSERVATIONS IN THE ANTARCTIC SEAS 



By M. Tamura and J. Sugiura, Central Meteorological Observatory, 



Japan 



The authors were engaged in weather observations in the Antarctic 

 Seas on board the Japanese whaling ship " Hashidate Maru," of 

 10,000 ton, from 4th December, 1947, to 8th March, 1948. The operation 

 tield of the ship covered sea area ranging from S. 63° 06' to S. 75° 41' 

 and from E. 148° 04' to W. 172° 08'. The results of weather observations" 

 will be summarized below. 



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