Page:Encyclopædia Britannica, Ninth Edition, v. 17.djvu/635



The following is a summary of the results arrived at by the Norwegian Meteorological Institute (1867-83). The

number of stations is from forty to fifty. The coldest parts of Norway, where the mean annual temperature is below 32° Fahr., are the highest regions of the country and the interior of Finmark (Karasjok, 26°.4); on the sea-shore it is only at Varanger Fjord that it falls below 32°. The highest mean annual temperature (44°.6) is that of Skudesnæs; and the outer coastal margin from the mouth of Sogne Fjord to Lindesnæs has a mean annual temperature of 44°. The interior of southern Norway and that of Finmark have the longest winter (200 days with a mean annual temperature of under 32°) and the lowest winter temperature, the mean temperature of the coldest day being under 14°. From the interior districts towards the coast the climate becomes everywhere milder in winter. From Lindesnæs an exceedingly narrow strip of land stretches along the west coast northwards right to the mouth of Throndhjem Fjord where the lowest mean temperature of any day exceeds 32°. Röst, the outermost of the Lofoten Islands, belongs to this strip of coast (32°.9 in January). The January isotherm for 32° reaches beyond Tromsö up to the 70th parallel of latitude; on the one side it extends down to the southern coast of Iceland, on the other to the alpine districts of Norway. In January the interior of Finmark has a temperature of 20°.5, central Norway, at an altitude of 1600 feet, 11°.3. The winter isotherms follow the contours of the coast and lie very close together. The summer is hottest in south-eastern Norway (Christiania, July, 61°.9); next come Hardanger (July, 58°.3) and Sogn (Sogndal, July, 60°.3). Karasjok has in July a mean temperature of 57°.2. On the coast the summer is colder than some distance inland; it is coldest on the Finmark coast (Vardö, July, 47°.7) and in the lofty inland tracts (Röros, 52°, 2000 feet above the sea). The interior of Finmark has a higher temperature (upwards of 57°) than any part of the outermost coastal margin as far south as Jæderen (59° N. lat.). The temperature in July (50°.2) at the North Cape (71° N. lat.) is the same as in the southern part of Iceland (63° to 64° N. lat.). The isotherm for 52° passes through the Lofotens (68° N. lat.) and the Shetland Isles (62° N. lat.); that for 56° extends from Jæderen straight across the North Sea to the northern part of Scotland. On reducing the temperature to the sea-level we get for the south-eastern part of Norway a maximum of heat exceeding 60°. The interior having a warm summer and a cold winter, and the coast a cool summer and a mild winter, the annual range of temperature is greatest throughout the inland regions (55° in Finmark, 45° in central Norway) and least on the coast—from Lindesnæs to Vardö. In Österdal and the interior of Finmark the mercury sometimes freezes (-40°). Along the outermost line of coast, from Romsdal to Jæderen, the mercury never sinks below 12°. At Karasjok a temperature of -58° has been observed. The highest known readings are those observed at Christiania (90°) and in Finmark (96° in the vicinity of Varanger Fjord). Throughout a tract extending straight across the country near the 65th parallel of latitude the maximum temperature does not reach that observed in the south-east and in Finmark. Along the coast the highest temperature is from 77° to 79°, and on the outermost skerries it hardly reaches 75°. The diurnal range of the temperature of the air is greatest in the south-east (Christiania, 15° in July, 3° in January), least on the coast (only 5° in July). In Finmark it is inappreciable during the dark season, when the sun is below the horizon throughout the twenty-four hours. At Vardö it is 5° in July. In spring the heat everywhere makes its way from the coast towards the interior of the country (in Finmark from north to south); in autumn the cold passes from the interior towards the sea (in Finmark from south to north). The thermic anomaly is in Norway during the winter months always positive; along the west coast it reaches as much as 36° in January, and off the Lofotens amounts to even 43°, the highest value it anywhere attains on the globe; even in central Norway it is +11° in January. In July it is greatest in Lapland, viz., +9°. Along a narrow strip of the south-western coast of Norway it is negative in the month of July, though hardly -2°; hence this strip of coast is comprised in the negative thermic anomaly of the North Atlantic during summer.

The tension of vapour is at all seasons of the year greatest on the coast and least in the interior of the country. The relative humidity is greatest on the coast of Finmark (82 per cent. per annum). Leirdal in Sogn, which lies under the lee of the Justedalsbræ, has an annual relative humidity of only 65 per cent. In winter it is greatest in the cold tracts of the interior (85 per cent.) and least on the west coast (70 per cent.); in summer it is greatest on the coast (upwards of 80 per cent.) and least in the interior (Christiania, 60 per cent.). On the driest days it can sink as low as 20 or even 12 per cent.

Just as the isotherms exhibit a tendency to follow the contours of the coast, so likewise do the isobars. In the mean for the year there is a maximum of pressure (reduced to the level of the sea and to the gravity at 45° lat.) in south-eastern Norway comprised within the isobar for 29.88 inches. The isobar for 29.84 inches extends from the north of Scotland over Bergen, Dovre, Throndhjem, and parallel with the coast of Nordland to Lapland. The isobar for 29.80 inches passes across Shetland and the coasts of Romsdal, Nordland, and Finmark to the south side of Varanger Fjord. The isobar for 29.76 inches passes a little to the north of the Faroe Islands, across the Lofotens, and along the Finmark coast to Vardö. Out in the Norwegian Sea there is a minimum pressure of air (29.72 inches), with its longitudinal axis stretching from south-west to north-east, between Iceland and Norway; it extends into the Barents Sea, between Beeren Eiland, Novaya Zemlya, and Finmark. In January the normal isobars take approximately the same course. Central Norway has a maximum of 29.97 inches. The isobar for 29.80 inches extends from the north coast of Ireland across Scotland to Stad and Lapland; that for 29.60 inches passes from the Faroe Islands towards the north east, off the coast of Norway. The least pressure of air in January is at the North Cape (29.64 inches). A minimum occurs east of Iceland (29.45 inches, a still lower