Page:EB1911 - Volume 21.djvu/991

Rh in the northern continents is below the normal in winter and above the normal in summer.

The “Fram” observations showed that while the ordinary diurnal range of temperature prevailed for the months when the sun was above the horizon during some part of the day, there was also a diurnal range in the winter months when the sun did not appear, the minimum then occurring about 2 p m. and the maximum about 1 a.m, the “day” being colder than the “night.” Except in July and August the temperature was always found to be lower with the weaker winds and higher with the stronger Winds irrespective of direction. Extraordinarily rapid variations of temperature have been observed in the winter months, on one occasion in February 1896 (north of 84° N.) the thermometer rising within 24 hours from −45·4° to +22·3° F., a rise of 67·7°.

Cloud and Precipitation.—The amount of cloud in the far north is greater in the daytime than at night, the summer months being cloudy, the winter very clear, and the amount is greater with the stronger winds and less with the weaker winds. Precipitation is most frequent in the summer months, the “Fram” results showing an average of 20 days per month from May to September; while from October to April the average was only 11 days per month. Rain was only observed in the months from May to September; but snow occurs in every month and is most frequent in May and June, least frequent in November and December, which are the months of minimum precipitation. It has never been possible to make satisfactory measurements of the amount of precipitation in the Arctic regions on account of the drifting of snow with high wind. Fogs occur most frequently in July and August (20 or 16 days per month); they are practically unknown between November and April.

Pressure.—The “Fram” observations enabled Professor Mohn to revise and extend the isobaric maps of Dr Buchan, the correctness of which was strikingly confirmed. The Atlantic and Pacific low pressure areas are found at all seasons on the margin of the Arctic area, the position shifting a little in longitude from month to month. The two low pressures are separated in the winter months by a ridge of high pressure (exceeding 30 00 in) stretching from the Canadian to the Siberian side between the North Pole and Bering Strait, this ridge has been termed by Professor Supan “the Arctic wind divide.” In April the high pressure over Asia gives way and an intense low pressure area takes its place during the summer, uniting in August with the less intense low-pressure area which develops later over Canada, and reducing the Arctic high pressure area to an irregular belt extending from North Greenland to Franz Josef Land on the Atlantic side of the Pole The general pressure over the polar area is much higher in winter than in summer and the gradients are steeper also in the cold weather, giving rise to stronger winds. The isobaric conditions indicate light variable winds in summer along the route of the “Fram” from the New Siberia Islands to the north of Spitsbergen, and in winter south-easterly or easterly winds of greater force, this is in accord with the observations made during the drift. Professor Mohn believes that the maximum pressure at the North Pole takes place in April, when it is about 30 08 in; and the minimum pressure from June to September, hen it is about 29 88 in., the annual range of monthly mean pressure being thus only 0·20 in., so that the Pole may be said to be in a region of permanently high atmospheric pressure. Cyclonic depressions crossed the region of the “Fram's” track with considerable frequency, 73 being experienced in the three years, the frequency being greatest in winter but the wind velocity in cyclones greatest in summer; the most common direction of movement was from west to east. The average velocity of the cyclonic winds encountered by the “Fram” was only about 29 m. per hour, the highest 40 m. per hour, the portion of the Arctic Sea she crossed being much less stormy than the coasts of the Arctic lands, where winds have been recorded of far greater severity, e.g. 45 m. per hour in Spitsbergen in 1882, 55 m. per hour in Teplitz Bay, Franz Josef Land, in 1900, 62 m. per hour on the Siberian coast in the “Vega” in 1879, and as much as 90 m per hour at Karmakul in Novaya Zemlya in 1883. There seems little doubt that the interior of the polar area is a fair weather zone as compared with its margins, where the contrast of the seasons is more marked.

Flora.—The land flora of the Arctic regions, although necessarily confined to the lower levels which are free from snow for some time every year, and greatly reduced in luxuriance and number of species as compared with the flora of the temperate zone, is still in its own way both rich and varied, and it extends to the most northerly land known. In some of the fjords of western Greenland and also of Ellesmere Land almost on the 80th parallel the prevailing colour of the landscape in summer is due to vegetation and not to rock. The plants which occur on the margin of the Arctic Sea and in the polar islands represent the hardier species of the North European, Asiatic and American flora, the total number of species amounting to probably about a thousand phanerogams and a still larger number of cryptograms. The habit of all is lowly, but some grasses grow to a height of 1 ft 6 in., and the mosses, of which the Eskimo make their lamp-wicks, frequently form cushions more than a foot in depth. Trees are absent north of 73° N, which is the extreme point reached in Siberia, or they are dwarfed to the height of shrubs as in southern Greenland, or farther north to that of the prevailing herbage. The flowers of many Arctic species of phanerogams have an intensely brilliant colour. The plains and lower slopes of the plateaux of Ellesmere Land and Heiberg Land and the plain of Peary Land north of Greenland are sufficiently clothed with vegetation to support large numbers of rodents and ruminants, the plants occurring not as occasional curiosities, but as the normal summer covering of the ground, playing their full part in the economy of nature. The cold of winter is not sufficient to put a stop to plant life even at the pole of cold in northern Siberia; and there is no reason to doubt that if there were islands close to the North Pole they would bear vegetation.

Fauna.—Animal life is comparatively abundant in the waters of the Arctic Sea, though the whalebone whale, Balaena mystecetis, has become almost extinct by reason of the energy with which its pursuit has been carried on. The white whale and narwhal still abound in the open waters as far north as ships can go. The walrus and several species of seal prey on the marine life, and the polar bear, the king of Arctic beasts, probably roams the whole surface of the frozen sea in pursuit of seals and the larger fish. The other Arctic carnivore include the Arctic fox and wolf, the latter attacking all the land mammalia except the polar bear and old musk-oxen. The wild reindeer is still found in all the circum-polar lands except Franz Josef Land; but its range does not extend so far to the north as that of the typical ruminant of the polar lands, the musk-ox (Ovibos moschatus), which now abounds only in Peary Land, north Greenland and in the American Arctic Archipelago, though it was formerly circum-polar in its distribution. The Arctic hare is almost equally characteristic and more abundant, and the lemming probably more common still. The ermine and other valuable fur-bearing animals also occur. The animals are either permanently white like the polar bear, or change their coats with the season, being brown in summer and white in winter like the hares and lemmings. The birds of the Arctic regions are all migrants, retreating southward in winter but nesting in incredible numbers on the Arctic coast-lands, and in summer probably finding their way as individuals to every part. They are mainly sea-birds, though the snow bunting, the Arctic owl and other land birds are amongst the summer visitors. It must be remembered that the elevated plateaux of the interior of Greenland and of many of the large islands are totally devoid of life of every kind on account of their unchanging covering of snow and the intensely rigorous climate due to their great altitude.

Arctic People.—The conditions of life in the continental parts of the Arctic regions are extremely severe as regards temperature in the winter, but it has been found possible for civilized people to live permanently both in the extreme north of North