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Saavel i Overfladen som langs Havbunden viser
saaledes Temperaturen sig lavere under Land end i sterre
Aistand fra Kysten. Der udgaar aabenbart fra Laudet
en afkjolende Virkning. Jeg beiuevuer dens Aarsag:
Land-kulden. og skal nedenfor gjöre Rede for dens Oprindelse
og Virkning.
Isothermerne for — 1» til ft» ligge i det Hele taget
meget tæt paa Kartet, hvad der har sin Grund dels i, at
Temperaturen varierer sterkt paa en kort Strækning, dels
i Bundens sterke Skrnaning. 1 det store Dyb. der
indtages af Kuldegrader under - 1°. er Temperaturens
Fordeling meget mere jevn og lader sig ikke fremstille, uden
at maa tager Tiendedelsgrader i Betragtning.
I Færø-Shetland-Renden gaar Temperaturen ned
under - I".t langs Rendens Bund. Mellem Island og
X orge findes i Xorsko-Dybct et Temperatur-Maxiamm
paa - 1».17 (Station 52) omgivet af koldere Vaad. Et
endnu niere udpru’get Maximum lindes mellem .Tan Maven
og Norge, med Temperaturer over — 1 ".’J. omgivet paa
alle Sider af lavere Temperaturer. Den laveste
Bundtemperatur timles i Grønlandshavet. Den gaar ned til — l».fi
ti! – I’M (tg uaar saaledes ikke Havvandets Frysepunkt
under almindeligt Tryk {o. — 2».U). Fra Grønlandshavet
mod Spidsbergen og Beeren-Eiland er Temperaturen stadig
stigende til ()". Fra den sydlige Del af dette Parti (72°.5
X. Br.) skyder sig (mellem 1»» og 15» E. Lgd.) langs
Bunden en bugtet Arm med koldere Vand, — 1».4 og — l.»3,
svdover mellem det ovennævnte Maximum paa 71» N. Br.
og de norske Banker lied i Lotbt-Dybet. hvor Isothernien for
— 1».3 omslutter et stone Omraade og naar ned til l>5».ö
X. Br. (Snit Ko. XIII. Pl. XI). Gjennem Jan
Maven-Renden skyde sig fra Grønlandshavet kolde Tunger med
Temperaturer paa — 1».5. — 1°.I og - 1°.3 mod Øst
henimod Norge, men uden, som det synes, ganske at naa det
sidst oven nævnte kolde Parti i Lofotdybet.
1 det sondre Bassin — Xorske-Dvbet — er
Temperaturen gjennemsnitlig højere end i det nordre Bassin —
Svenske-Dybet.
Tversnit og Karter vise saaledes en ejendommelig
Fordeling af Temperaturen i Nordhavet. Medens i
Atlanterhavet, ligesom i Nordhavet. Temperaturen saagodtsom
overalt aftager fra Overfladen mod Dybet, finde vi i det
förste endnu Varmegrader ved Bunden, medens vi i det
sidste finde det dybere og større Parti indtaget af Vand
med Kuldegrader. Grændsen mellem begge Have, der
saa bestemt angives ved de undersøiske Rygge, der danne
CH uafbrudt. Forbindelse mellem Skotland og Grenland over
Færøerne og Island, skiller ogsaa mellem Atlanterhavets varme
Vand i Dybet og Nordhavets iskolde. Det iskolde Vand
rækker i Færo-Slietlaml-Rendeii netop op til, paa et enkelt
Sted kanske lidt over. Wyville Thomson-Ryggens Kam.
Island-Færo-Ryggen ligger højere. I Daumarkstrædet. ræk-
tlie water is iee-eold. out OB the bank warmer. On Ille
Jan-Maven Bank oeeurs a limited tract with water above 0°.
Both at the surface and along the sea-bed, the
temperature is accordingly found to be lower in close
proximity to land than at some distance from the coast. It is
obvious that a cooling influence issues from the land. The
cause of this I designate: the land-cold, and in the sequel
I shall explain its origin and effects.
The isotherms for - 1» to 5» generally lie very c lose
together on the map, which arises partly from the
temperature exhibiting considerable variation over a limited area,
partly from tile rapid decline of the bottom. In the great
deep, that has a temperature under — 1», the distribution
of temperature is much more equable, and does not admit
of being represented without having recourse to tenths of
a degree. In the Færoe-Shetland Channel, the temperature
falls below — l».l along the bottom. Between Iceland
and Norway, we have in the Norway Deep a
temperature-nmximum of — 1". 17 (Station 52), surrounded by colder
water. A maximum more prominent still occurs between
-Ian ptfayen and Norway, with a temperature over — l».2,
enclosed on all sides by a lower. The lowest
bottom-temperature is mot with in the Greenland Sea. It reaches down
to — l°.ti or — 1».7. and does not therefore attain the
freezing-point for Sea-water under ordinary pressure (about
— 2°.01. From the Greenland Sea towards Spitzbergen and
Beeren Eiland. the temperature rises steadily up to 11°.
From the southern part of this tract (lat. 72».ft N),
a sinuous arm, with colder water, — 1».4 and 1°.3,
strikes off (between long. 10° and 15» E) along the bottom,
passing southward between the aforesaid maximum in lat.
71» N and the Norway Banks down into the Lofoten
Deep. The isotherm for — lp.3 encompasses a
considerable area, reaching as far south as lat. 0ö».5 X
(Section XIII, PI. Nil. Through the Jan-Mayen Channel,
cold isothermal tongues, with temperatures — IV). — l’J,
and — 1».3, extend eastward from the Greenland Sea
towards Norway, vet without, it, would seem, quite
reaching the last-mentioned cold tract in the Lofoten Deep.
In the southern basin — the Norway Deep — the
temperature is higher on an average than in the northern
basin — the Swedish Deep.
Hence, the vertical sections and the maps show a peculiar
distribution of temperature in tile North Ocean. While
the temperature, alike in the Atlantic and the North Ocean,
almost everywhere diminishes from the surface to the deep,
a temperature above 0» is still found to occur in the former
at the bottom, whereas in the latter the deeper and more
extensive tract is filled with water having a temperature below
(I". The boundary between the two seas, so prominently
determined by the submarine ridges that constitute an
uninterrupted line of connexion between Scotland and
Greenland past the Færoes and Iceland, likewise serves to
separate the warm water in the depths of the Atlantic from
the ice-cold water ol’ the North Ocean. The ice-cold
water reaches in the Færoe-Shetland Channel just up to
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