Jökull - 01.12.2007, Page 66

Jónsdóttir and Sveinbjörnsson
Figure 3. Sea-ice observed along
a 287 km long survey line (top)
between Iceland and Greenland,
based on sea-ice charts from the
Institute of Earth Sciences (Jóns-
dóttir, 2007). Zero indicates that
the ice has reached Iceland whe-
reas 287 denotes icefree condi-
tions within these waters. – Fjar-
lægð að hafís á 287 km mæli-
línu á milli Íslands og Græn-
lands. Lág gildi sýna að hafísinn
er nærri Íslandi en há gildi að lít-
ill hafís er á svæðinu.
THE SEA-ICE CONDITIONS OFF
ICELAND IN 2007
Throughout 2007, sea-ice conditions in Icelandic wa-
ters weremonitored usingmainly ENVISAT,MODIS,
NOAA, Quickscat and AMSR images. The GIS sys-
tem ArcInfo was used to enhance, interpret and com-
pare different images in order to assess sea-ice condi-
tions. Sea-ice charts based on these images were pu-
blished on the web (Jónsdóttir, 2007), with warnings
regarding the unstable behaviour of sea ice causing
rapid change in sea-ice conditions.
Repeated measurements of the distance to any ob-
served sea ice, other than icebergs, along a line mar-
king the shortest distance between Iceland and Green-
land (Figure 3) serves as an approximate measure
of sea-ice conditions in this region. The graph do-
cuments the presence of sea ice in Icelandic waters
but is only an indirect indicator of sea-ice budget,
since it does not take into account variations in sea-ice
64 JÖKULL No. 57