Jökull - 01.12.1969, Blaðsíða 31

1871 1881 1891 1901 1911 1921 1931 1941 1951 1961 1971
-1875 -1885 -1895 -1905 -1915 -1925 -1935 -1945 -1955 -1965 -1975
Fig. 8. Variations in the irequency of clrift ice in the Icelanclic coastal area in March—May
ancl sea surface temperature variations March—May at Grímsey. 5-year running means.
largefy on the influx of Atlantic water from
the southwest. A priori it was expected that
the intensity of the Atlantic influx would be
related to meteorological conditions, especially
in the area west and northwest of Iceland. An
investigation of this relationship indicated a
rather close correlation between the hydro-
graphic conditions at intermediate depths north
of Iceiand (and also surface temperature) and
meteorologicaf variables in the preceding
period. In the region west of Grímsey the
strongest correlation of temperature or salinity
with the south-north wind component was
found for the average monthly wind compon-
ent 11/2 month prior to the date of the oceano-
graphic observations. East of Langanes the best
correlation was found for a time difference of
3 months. These time lags correspond roughly
to the transport time of water from the region
off the northwest coast to the locality in ques-
tion.
This relationship has been re-examined and
testecl statistically using more recent data
(Stefánsson and Guðtnundsson 1969). The stati-
stical analysis confirmed the previous hypo-
thesis of a strong connection between the
oceanographic conditions off Langanes in Au-
gust and meteorological factors about 3 months
prior to the observations. Furthermore, it ap-
peared that the air temperature is a more
important factor than the winds, although the
hypothesis of an independent effect of the
wind coukl not be rejected. The relationship
with air temperature was explained by the fact
that the warming up will have a greater effect
on the density of the inshore water than that
of the offshore water, leading to increased
horizontal pressure gradient in offshore direc-
JÖKULL 19. ÁR 27