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189
sig ud over Nordsøen, og indtager i sin Bevægelse langs
Continentets Kyster de øvre Lag lige til Novaja Semlja
og Spidsbergen. Ombøjet af Grønlandshavets Nordenvinde
gaar det atlantiske Vand for en stor Del atter sydover
langs Polarstrømmens Østgrændse, passerer østenfor Jan
Mayen og svinger, østenfor Island, igjen ned i den centrale
Del af det norske Hav.
Fra Færø-Shetland Renden af, hvor det atlantiske
Vand afkjøles af det underliggende kolde Vand, som det
selv ved sin Bevægelse er virksomt til at suge ind over
Rendens Bund fra Norske-Dybet, synker det salte Vand
med den saaledes erhvervede større Tæthed nedover og
optræder ved Rendens Munding som iskoldt Vand af atlantisk
specifisk Vægt i 500 Favnes Dyb. Længere mod Nord,
mellem Island og Norge, danner det et Trykmaximum med
Temperaturmaximum og Tæthedsmaximuin samt
Luftholdig-hedsminimum igjennem alle de dybere Lag.
Mellem Jan Mayen og Norge danner ogsaa det
tungere atlantiske Vand i Dybet et Trykmaximum med
Temperaturmaximum og Tæthedsmaximuin samt Minimum af
Luftholdighed, afkjølet som det bliver paa Syd-, Nord- og
Vestsiden af koldere Vand.
Samtidig sender det indre Polarhav sine kolde og
ved Issiueltning opspædede Vandmasser ned i Nordhavet
langs Grønlands Østkyst. De øvre Lag finde igjen sit
Udløb gjennem den nordlige Del af Danmarkstrædet, medens
en mindre Del strømmer gjennem Jan Mayen-Renden
østenfor Island ind i det norske Hav.
Imellem Grønland og Spidsbergen gaar i de dybere
Lag Polarstrømmens Vand mod Dybet, ligesaa østenfor
Jan Mayen og i Jan Mayen-Rendens vestlige Del.
Gjennem disse Strømninger føres det fra det indre Polarhav
kommende og i Overfladen om Vinteren afkjølede Vand
ned i Dybene i Nordhavet. Det møder her det synkende
atlantiske Vand. Polarvandet opvarmes og
Atlanterhavsvandet afkjøles.
I 74° og i G8° Bredde stiger det kolde Vand fra
Dybet op til højere Niveauer. Her have vi de nedstigende
Strømmes Compensationsstrønime.
I det søndre Bækken ere de nedstigende Strømme
varmere end i det nordre, og det sainnie bliver Tilfældet
med de opstigende. Den laveste Temperatur ved Bunden
er —1°.36. I det nordre Bækken er den laveste
Temperatur paa Bunden i den hidtil udforskede Del af Havet
—1°.7. Under den polare Vinter afkjøles Havvandet til
—2°. 1. Men denne Temperatur træffes ikke i Dybet. I
dette er Temperaturen højere. Det nedsynkende atlantiske
Vand har opvarmet Dybet. Denne Opvarmning finder især
Sted i det sydlige Bækken, hvor Atlanterhavsvandet
fornemmelig kommer til Synkning. I det nordlige Bækken er
of Iceland, along the south, the west, the north, and the
east sides of that island, by circuitous routes into the
Norwegian Sea. Here it is suffused over the North Sea, and,
on its course along the coasts of the continent, occupies the
higher strata, as far north as Novaja Semlja and
Spitzbergen. Turned aside by the north winds of the
Greenland Sea, the Atlantic water passes in great part again
southward, along the eastern limit of the Polar
current, flows to the east of Jan Mayen, and then rounds off
again, east of Iceland, into the central portion of the
Norwegian Sea.
From the Færoe-Shetland Channel, where the Atlantic
water is cooled by the subjacent cold water, which by its
own motion it is effective to draw in over the bottom of
the channel from the Norway Deep, the salt water sinks
by reason of the greater density thus acquired, and is mot
with at the mouth of the channel as ice-cold water of
Atlantic specific gravity, 500 fathoms deep. Farther north,
between Iceland and Norway, it constitutes a
pressure-maximum, together with a temperature-maximum and a
density-maximum, as also a minimum of air-content — throughout all
the deeper strata.
Between Jan Mayen and Norway, the heavier Atlantic
water likewise constitutes in the deep a pressure-maximum,
along with a temperature-maximum and a density-maximum,
as also a minimum of air-content, cooled as it is on the
south, north, and west sides by colder water.
Simultaneously, the inner tracts of the Polar Sea send
their cold masses of water, diluted by the melting of
ice, down into the North Ocean, along the east coast
of Greenland. The upper strata find their outlet through
the northern part of Denmark Strait, whereas a smaller
portion of the water passes through the Jan-Mayen
Channel, east of Iceland, and thence into the Norwegian Sea.
Between Greenland and Spitzbergen, the water of
the Polar current passes in the lower strata into the
deep, as is also the case east of Jan Mayen and in the
western part of the Jan-Mayen Channel. By these currents,
the water coming from the inner tracts of the Polar Sea,
and cooled during winter at the surface, is carried into
the deeps of the North Ocean. Here it meets the sinking
Atlantic water. The Polar water is warmed, the Atlantic
water is cooled.
In lat. 74° N and lat. 68° N, the cold water from the
deep rises to higher levels. Here, we have the
compensation-currents of the descending currents.
In the southern basin, the descending currents are
warmer than in the northern; and the same, too, is the
case with the ascending. The lowest temperature at the
bottom is —1°.3(>. In the northern basin, the lowest
temperature at the bottom in the hitherto explored part of
the Sea is —1".7. During the Arctic winter, the water
of the sea is cooled down to—2°.l. But this temperature
is not met with in the deep. There, the temperature is
higher. The sinking Atlantic water has warmed the lower
strata. This heating takes place more especially
throughout the southern basin, where the Atlantic water in par-
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