Fróðskaparrit - 01.01.2005, Qupperneq 156

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NEWS AND PROGRESS 2004
area. Topographical effects on surface cir-
culation were weakened when stratifica-
tion increased. During stratified conditions
winds had a strong impact on surface cir-
culation and shelf-ocean exchange, and the
wind direction was crucial for drift paths
and residence times for particles (e.g.
plankton) in the shelf area. When strati-
fication was weak, tidal effects combined
with topographic steering dominated the
circulation. The tidal currents are strong
over the shelf, where the enhancement of
the K1 component was most pronounced
for weak stratification. The M2 component
was shown to be more prominent during
stratified conditions. Freshwater runoff
combined with northerly winds along the
coast can result in a shallow and low salin-
ity surface layer over the shelf, as observed
in summer, and also during anomalous
melting events during winter and spring.
Thus, local fjord/near coast processes can
very well influence stratification and dy-
namics over the shelf, and factors such as
prevailing wind direction and the amount
of freshwater supply from the adjacent
coast are important when interpreting vari-
ability in biological production and plank-
ton distribution in this region. Air and sea
surface temperatures were well inter-cor-
related between all stations along the fjord-
coast transects, indicating that the fjord and
coastal region in question (i.e. Troms north
of Vesterálen, and Finnmark) is a coherent
climatic region. The sea temperatures in
this region are to a higher degree being
controlled by local climatic processes (i.e.
air-sea heat exchange) than what is the case
further south. Our analysis showed that the
mean heat loss to the atmosphere from Por-
sanger, a fjord with no sill, was twice as
large as the mean heat loss from the sill-
fjord Balsfjorden. This difference can be
explained by different inflow of water car-
rying heat to the fjords, controlled by the
topographic differences. No clear heating
or cooling trends could be seen from our
temperature time series, and additional pe-
riodic data back to 1930 revealed anoma-
lies well within the ones observed for the
1980-2003 period.