DISCUSSION OF CERTAIN CONCLUSIONS DRAWN FROM THE STUDY OF THE 



SYNCHRONOUS CHARTS OF SEA-LEVEL PRESSURE FOR NOON G.M.T. 



WITH WIND AND AIR TEMPERATURE. 



THE PATHS or THE CYCLONIC DEnuBOOHB or THE SOUTHERN OCEAN. 



Hitherto adequate information has been wanting for the purpose of defining the average path* of 

 cyclonic depressions which visit the Southern Ocean and Southern Continents during the several seasons 

 of the year, and this information these eircumpolar chart* to some extent supply. 



An attempt was made by the present writer in the year 1890 to determine, by the aid of observation* 

 extracted from a large number of logs relating to voyages between the Cape of Good Hope and Australaria 

 during the three years 1887-9, tbe mean paths of the centres of cyclonic system* moving eastward South 

 of the 38th parallel of latitude,* and subsequently to trace the centres of high- and low-pressure system* 

 in transit eastward over Australasia, t by reference principally to synoptic charts prepared at the Sydney 

 Observatory under the direction of the late Mr. H. C. Ri'sssix, then Government Astronomer for New 

 South Wales. 



From the information obtained by means of the data contained in the log* referred to it was inferred 

 that East of the 30th meridian of Ea*t longitude the centre* of atmospheric disturbance* appeared to 

 travel to the eastward usually on paths lying South of the 43rd parallel of latitude during winter month* 

 and South of the 46th parallel during summer months. The evidence afforded by the daily synoptic 

 chart* of Australasia also appeared to favour this assumption, which is now confirmed by the testimony of 

 the daily chart* under notice. 



In a memoir by the writer upon the Climatology of South Victoria Land and the Neighbouring Seaa,t 

 which is included in the published result* of meteorological observations of the " Discovery " Expedition, 

 during the years 1901 to 1904, attention is directed to the exceptionally favourable position, regarded a* 

 ft meteorological station in the Southern Ocean, in which the Winter Quarters of the Exploring Ship 

 "Gauss," of the German Antarctic Expedition, was situated. The value of the data obtained at this 

 station, on the fringe of Antarctica, is, moreover, considerably enhanced by observations recorded at the 

 German station on Kerguelen Island, because together they throw light upon point* in connexion with 

 the surface distribution of pressure and wind in cyclonic system* of the Southern Ocean, in regard to 

 which little ha* hitherto been known. 



The following remarks in thi* connexion, which appear in the memoir referred to, are based upon the 

 date incorporated in the daily charts; it is, therefore, considered admissible to repeat them in these 



- 



Lying to the South of the westerly wind* of the Southern Ocean, and at the limit* of the southern 

 segment of those low-prenure areas which move from We*t to East with the westerly air current of the 

 Southern Hemisphere, the Winter Quarter* of the German Antarctic Expedition were exceptionally well 

 situated as an observing station from a meteorological point of view. 



It has been thought by meteorologists, who have attacked the problem, that, associated with the 

 depressions which traverse tbe Southern Oceans, depressions which are usually elliptical in shape and have 

 their major axes extended in a northerly and southerly direction, the easterly winds in the southern 

 segment of the system are almost always light or moderate in force. Ships running down the easting in 



-Wind SyiUBM and Trade Bomtee between the Cape of Good llope and Anetimlie," 'Quarterly Journal, Royal 

 Metsoroloycul Society,' Vol. XVII. (1891), pp. 21-27. 



I he Track* of Orran Wind ByHenw in Tnnait arrow ABetnOaata," ' Quarterly Journal. Royal Meteorological Sorirt y. 1 

 Vol. XIX. (ISM), pp. 4-*a 



J - ninnllllnij nf Victoria Land sad DM Seifhboorinf Sea*,"' National Antarctic Expedition, Mrteorolo(y,' Fart I. 



C 



