Jökull - 01.12.1969, Síða 32

tion and tlius giving rise to increased geo-
strophic circulation around the country. Sea-
sonal variations in the influx o£ Atlantic water
support this conclusion.
The statistical investigations here rclerred to
also showed that the correlation between
oceanographical and past meteorological condi-
tions was poorer for the years 1963—1965 than
for previous years. This result was not surpris-
ing, since observations of recent years have in-
dicated an increased polar influence in the
arctic and winter-formed waters mixing with
the Atlantic water entering the shelf area from
the Irminger Sea (see e.g. Malmberg 1967).
It remains to consider the last factor men-
tioned, viz. variations in the properties, exten-
sion and current velocities of Atlantic water
in the Irminger Sea. Very little is known about
such fluctuations. However, they might affect
the north-flowing Irminger Current ancl there-
by conditions north of Iceland. 7'he relation-
ship between the atmospheric circulation and
sea surface temperature in thc North Atlantic
has been investigated by Rodewald (1967).
Studies made by Rlindheim (1968) of observa-
tional data from the Ocean Weather Station
Alpha supplimented by hydrographic sections
in the western Irminger Sea indicate that the
volume of Atfantic water transported to the
Irminger Sea varies from year to year. Tltus
in 1960 Atlantic ínfluence was exceptionally
pronounced in the western branch of the Irm-
inger Current, but the opposite was true in
1954 and 1956. Blindheim points out that in
periods of prevailing northeasterly winds in
the area south of Iceland relatively greater
amounts of Atlantic water than usual may be
fed into the Irminger Current, while another
reason for variations in the Irminger Current
may !ie in associated variations in the entire
North Atlantic Current. Such variable trans-
ports o£ water and heat might in turn influ-
ence the atmospheric conditions ancl tlius lead
to changes in the current systems.
From tlte preceding discussion it is clear
that the observed temperature variations in
the area north of Iceland are the result of a
complex interplay of various oceanographical
and meteorological factors. Therefore, it will
by no nteans be a simple matter to make
oceanographical íorecasts for the North Ice-
landic coastal area. It is concluded, however,
that in favourable ice years the hydrography of
the area depends primarily on past meteoro-
logical conditions at the west and north coasts
whereas in heavy ice years the clistribution of
drift ice is the dominating factor.
REFERENCES
Blindheirn, Johan. 1968: Hydrographic in-
vestigations in the Irminger Sea in the
years 1954—1964. Fisk. Dir. Skr. Havund-
ers., 14: 72-97.
Eyþórsson, Jón. 1949: Temperature variations
in Iceland. Glaciers and Climate. Geogr.
Ann. 1949, H. 1-2.
Malmberg, S. A. 1967: Breytingar á ástandi
sjávar rnilli íslancls og Jan Mayen. Ægir,
12: 1-4.
Rodewald, Martin. 1967: Recent variations of
North Atlantic sea surface temperatures
(SST) and the “Type-Tendencies” o£ the
atmospheric circulation. Selected papers
from a special meeting of the environ-
mental committee, May, 1967. ICNAF Red-
book 1967, Part IV: 6-23.
Stefánsson, Unnsteinn. 1954: Temperature
variations in the North Icelandic coastal
area. Rit Fiskideildar, 2 (2): 27 pp.
— 1962: North Icelandic Waters. Rit Fiski-
deildar, 3: 269 pp.
— ancl Þórunn ÞórÖardóttir. 1965: Nutrient-
productivity relations in Icelandic waters
in June 1984. ICES, C. M. 1965, No. 170.
— and Guðrnundur Guðmundsson, 1969:
Hydrographic conditions off the northeast
coast of Iceland in relation to meteoro-
logical factors. Tellus, 21 (2): 245-258.
28 JÖKULl 19. ÁR