National Geographic : 1899 Dec
THE ANTARCTIC CLIMATE cember, January, and February as summer, we may take it that the mean winter temperature is - 16.80 C . (1.80 F.), and the mean for sum mer -1.5° C. (29.30 F.) . From his observations, Mr Arctowski concludes that between the sev entieth and seventy-first parallels of the southern hemisphere and amid the ice of the Antarctic ocean-first, the mean temperature is lower than that of the northern coast of Spitzbergen (Mossel bay, 1872-'73, - 8.90 C. (16.00 F.) ); second, the minimum temperature is quite as low as the minima observed on the east side of Greenland (Sabine island and Scoresby sound) ; and, third, the mean temperature of the three summer months is lower than the corresponding mean in the ice of the Arctic ocean. If we consider that a. considerable fraction of the seventieth par allel of south latitude is land, we can suppose that it may have a mean temperature as low as the 700 N., and include a pole of cold with lower temperature as the Asiatic or North American poles of cold. During the drift in the pack-ice hourly observations were made with a marine barometer and with an aneroid. While Mr Arctowski has not yet been able to apply exact corrections to these observations, the uncor rected values are near enough for present purposes. The lowest pressure observed during the winter was 711.74 mm. (28.022 inches), and the highest 772.14 (30.400 inches). The mean value of the monthly variations of the barometer, amounting to 34.30 mm. (1.350 inches), shows very clearly that the cyclonic belt extends beyond the polar circle. The three months of almost continuous daylight (November, December, and January) are characterized by a very small variation of pressure-only 23.95 mm. (.943 inch). The three corresponding months of winter have also a mean less than those for the intermediate or equinoctial months. The differences between the annual and monthly means show that Feb ruary, March, and April form a negative group, in which pressure is relatively low; the three months of polar night form another group of maximum barometric pressure; then follow August, September, and October-months of decreasing pressure-a group which, although not exactly negative, forms a distinct secondary minimum ; and, lastly, three months of polar day forming a secondary maximum of pressure. The existence of a direct, simple relation between the barometric pressure and the progress of the sun is at once obvious. The winds blew from northerly and southerly points with almost equal frequency, but easterly winds predominated over westerly. The sky was usually overcast, most frequently with a thick layer of stratus which formed a uniform gray covering and often persisted for days or even weeks together, with only short breaks. The number of days dur ing which the air did not remain saturated -i . e., on which the hygrom eter indicated a humidity of less than 90 per cent-was October, 12; November, 18; December, 22; January, 15, and February, 11. If ice deposits from fog and similar precipitation are included, snowfall is re corded on 257 days and rain on 14 days of the year. Speaking generally, it may be said that the weather was extremely cloudy; that fogs were frequent; that snow fell on many days, and that the air was saturated nearly the whole time.