NA TURE 



METEOROLOGY IN SOUTH 

 LAND^ 



[December 17, 1908 



10 a.m. being the principal 



\A7HEX the Discovery sailed for the Antarctic regions 

 in August, 1901, Captain .Scott took out an equip- 

 ment of meteorological instruments, but the men who were 

 to have used them were not on board. When South 

 \'ictoria Land was reached, the observations, therefore, 

 had to be made by men who had not been trained for the 

 work. The report on the observations which were made 

 by Lieut. C. W. R. Royds and assistants shows that they 

 are to be congratulated on their success in carrying out 

 arrangements for the exposure of the instruments and 

 their devotion in maintaining the readings during their 

 stay in South Victoria Land. 



The first volume of the report contains the observations 

 made at the winter quarters of the Discovery at Ross 

 Island, and also those made on sledge journeys from 

 there at various times during igo2 

 and 1903. These have been examined 

 and tabulated at the Meteorological 

 Office under the direction of Dr. 

 W. N. Shaw, and have been discussed 

 in sections bv Commander Campbell 

 Hepworth, Mr. R. H. Curtis, Dr. C. 

 Chree, F.R.S., Mr. W. H. Dines, 

 F.R.S., and Mr. C. T. R. Wilson, 

 F.R.S. The preface is by Dr. W. N". 

 Shaw, and Lieut. Royds has written 

 the introduction, giving details as to 

 the exposure of the instruments. 



The Discovery's winter quarters 

 were in lat. 77° 50' 50" S. and long. 

 166° 44' 45" E., and observations were 

 made every two hours from February 

 9, 1902, to February 15, 1904. Whilst 

 the Discovery was at Ross Island it 

 was remarkable how infrequently did 

 the thermometers register tempera- 

 tures above freezing point, the maxi- 

 mum reading being only 42° F. The 

 lowest reading was — 58°-5 F. Yet 

 it is noted that the ship was in a 

 position much warmer than the 

 regions surrounding. 



The fluctuations of the temperature 

 were rapid and violent, and generally 

 associated with a change of wind 

 direction. A south wind often brought 

 a rise of temperature. The alcohol 

 minimum thermometer was read and 

 re-set every two hours, and when the 

 observations were compared with the 

 readings of the adjacent mercury 

 thermometers the fact was brought 

 out that there was a minimum in 

 almost every two-hour period, and the 

 thermograph readings also show this. 



The summers were notably cold ; 

 the highest mean temperature for any 

 month was 26°.2 F., this being the 

 mean for December, 1903. The 

 coldest month was July, 1903, the 

 mean temperature' being — 2i°.o F. 'J'hese are the values 

 given in the preface and in one of the tables, but there 

 are two other tables which give different months and 

 temperatures. During April, 1903, the temperature never 

 exceeded 0° F. 



Discussing the readings of the minimum thermometer, 

 it is shown that the lowest readings of the day oftenest 

 occurred within two hours of midnight. A table is given 

 showing the percentage frequency of the occurrence of 

 (he minimum of the day in each two-hour period. These 

 values are given monthly and seasonally. On 37 per cent, 

 of days the principal minimum occurred between 10 p.m. 

 and 2 a.m. The values for the winter season show the 

 maximum frequency at this period of the day, and also a 

 ..econdary maximum between noon and 2 p.m., the mini- 



VICTORIA I "'■"'" occurring at 8 a. 

 one. 



This table is put forward as very strong evidence that 

 during the Antarctic winter night the temperature is 

 affected by diurnal and semi-diurnal influences. The mean 

 daily variation of temperature amounts only to 3° in 

 summer and 1° in winter. 



The sunshine recorder was not set up until September 

 14, 1902, and there is no record after February 15, 1904. 

 The amount of sunshine recorded is remarkably great. 

 In December, 1903, 490 hours were registered, this being 

 66 per cent, of the total possible. There were several 

 notable spells of continuous sunshine ; thus in December, 

 igo2, there was a period of eighty-seven hours' unbroken 

 sunshine, and in December, 1903, one of seventy hours. 

 During the twelve days December 6—17, 1903, there were 

 only fifteen hours without sunshine. 



The amoimt of cloud was observed and recorded 7890 



-Map of s 



National .'intarctic Expedition, T901-4." Meteorology, P.irt 

 servations at Winter Quarters and on Sledge Tourneys, with di=CM«i 

 various Authors. Pp. .viv+548. (London : Royal Society, 1908.) 



NO. 2042, VOL. 70] 



xtremity uf Ro^s Island, sho.vin5 winter quirteij of H.M.S. Discovery. 



times. Less than one-tenth of the sky was occupied by 

 clouds in 37-5 per cent, of the cases ; 43 per cent, of the 

 observations record that more than eight-tenths of the 

 sky were clouded. The winter months were least cloudy. 



Although the readings of the wet- and dry-bulb thermo- 

 meters were recorded, the values for humidity have not 

 been tabulated, as it is the opinion of meteorologists thai 

 the relative humidity values obtained from very low 

 thermometer readings are much open to doubt. The data 

 are, however, sufficiently definite to show that the climate 

 of Ross Island is undoubtedly very dry. 



Observations with a black-bulb thermometer in vacuo 

 gave remarkable results in the form of high readings. 

 Thus for the month of December, 1902, when the mean 

 temperature was 23°- 1 F., the average maximum on the 

 black bulb was 123° F., and in January, 1903, only on 

 one day did this thermometer fail to register 100° F. It 

 is argued that the air over the .Antarctic regions must bo 



